Standard-Stromversorgungslösungen und Anwendungen für AC/DC- und DC/DC-Leistungswandler

The function of AC/DC and DC/DC converters in an Electronic System design

Designers of power supplies will find that the advantages of using good quality AC/DC Power Supplies, DC/DC Converters, and Switching Regulators in their design architectures, will lead to a high reliability final product that end users will appreciate. There are numerous design needs for compact power supplies in a wide variety of applications such as medical, test & measurement, industrial, mobility, automation, Internet of Things (IoT), high power density, and so much more.

Electronic devices, that need to be plugged into an outlet, will require a quality AC/DC converter that will convert from the AC power input to DC power output. In a great majority of electronic design architectures, semiconductor devices typically operate via DC power.

DC to DC converters are typically selected to power designs with a voltage that is regulated and stable, especially when the input a source is fluctuating or is not stable. These kinds of power converters are designed with the use of high frequency switching circuits, coupled with inductors, switches, and capacitors that will help reduce the switching noise in the system and lead to, a solid and stable, regulated DC voltage output.

A basic DC/DC converter overview

The Buck Converter

The step-down (buck) converter is able to convert a higher DC input voltage at its input and transform that into a stabilized, but lower, DC voltage at its output. See Figure 1.



Figure 1: An example of a simple DC/DC Buck Converter Voltage Regulator (Image from Reference 1)


Buck converters have decided advantages in that their losses are quite low, and will be able to reach efficiencies higher than 97%. Their switching frequencies will be up in the many hundreds of kHz; this will lead to a very good power density architecture via the use of smaller inductors along with a fast transient response capability. When the FET switch is disabled, during its switching cycle, the output level will drop to zero. This enables the no-load power consumption to achieve a very low level. All of these advantages make the buck regulator quite an attractive replacement for a linear voltage regulator in quite a few applications.

There is a disadvantage with the buck converter, due to the fact that the Pulse Width Modulation (PWM) regulator feedback circuit will need to have a minimum output ripple to reach proper regulation. This is because the regulation is usually cycle-by-cycle. In addition, the output ripple will be dependent on the duty cycle, which will be a maximum at 50%. In this case, it will not possible to achieve ripple and noise down to μV levels, which can be achieved by linear regulators which are non-switching.

In the event that a designer requires a cleaner power supply, a linear regulator can be placed after a buck regulator, in order to achieve the best performance from both topologies. This is made possible since the linear regulator Power Supply Rejection Ratio (PSRR) will greatly reduce ripple/noise at its output.

The Boost Converter

A step-up, or boost converter power design, will convert a lower input voltage into a stable and solid, higher voltage at the output. Figure 2.



Figure 2: An example of a simple DC/DC Boost Converter Regulator (Image from Reference 1)


The advantage of using a boost converter architecture is that the output voltage is able to be varied with the mark-space ratio (this is the ratio between the high time and the low time). This is actually the duty cycle. For example, a 50% duty cycle is when the voltage high time is equal to the voltage low time of the Pulse width modulator (PWM) signal in order to be equal to, or ‘boosted’ above, the input voltage VIN.

This functionality enables the use of the Boost Converter to be quite useful, for example, in boosting a low battery voltage output to, a more useful, higher voltage level. However, a boost ratio that is more than two or three times the input, will make feedback stability much more difficult to maintain at a solid level. In addition, since the input current pulses will increase proportionally, as compared to the boost gain, a converter which triples its input voltage will draw three times its input current. This level of pulsed input current can even lead to increased EMI, as well as, voltage drop levels at the battery input leads.

One other disadvantage, of the boost converter topology, is that its output cannot be switched off, without the addition of a second switch, placed in series with the input. This is because just disabling the PWM controller alone will not disconnect the load from the input.

Power designers must be aware that, with the Boost Converter, they should not allow its input voltage to rise higher than its output voltage. In such a case, the PWM controller could then keep S1, in Figure 3, open continuously. In this case the input and output would be connected directly from L1 and D1 without regulation. Highly damaging currents may flow that can fast damage the converter along with its load. If designers are not able to avoid this condition, a replacement topology, which permits both buck and boost operation, will be necessary.

Buck-Boost (Inverting) Converter

The buck-boost converter, aka inverting ‘flyback’ converter, is able to convert an input voltage to a regulated, negative output voltage which is able to go higher or lower, than the absolute value level of that input voltage. The image in Figure 3 shows a simplified schematic of the Buck/Boost converter.



Figure 3: A simplified schematic of a Buck/Boost regulator (Image from Reference 1)


The buck/boost converter has a nice feature: the input voltage may be higher or lower than the regulated output voltage. Having such a capability, can prove useful for any applications that may require a stabilized voltage output from a battery which can have a terminal voltage between 9V, when discharged, to a fully charged 14V. Buck/Boost converters can prove quite useful in stabilizing the outputs of photovoltaic cells. Solar cells are able to deliver quite high voltage and current when in bright sunlight, but will revert to low voltage and low current when the sun is blocked or its light is diminished on a cloudy day. As the voltage/current relationship changes in such an example, a buck/boost converter can be quite useful for maximum power point tracking (MPPT) since the input/output voltage ratio can be continuously adjusted.

The greatest disadvantage of the buck/boost converter is its inverted output voltage. Here, if used in conjunction with a battery, the output voltage inversion is irrelevant, due to the battery supply which can be left floating and the -VOUT may then be connected to ground, in order to give a positive-going output voltage. Another disadvantage here is that the switch S1 is without a ground connection. This means that a level translator will be needed in the PWM output circuit; this can quickly add cost and complexity to the design.

DC/DC Converter applications

DC/DC converters have a great many applications in the electronics industry. In this section we will discuss the primary application areas for DC/DC converters.

Automation

In general, the main requirements for DC/DC power supplies to be used in automation applications are the importance of isolation. This would ensure that the power design avoid any interference with other equipment. The DC/DC should also be designed into a system, taking care to avoid any ground loops or potential differences that may disturb the operation of the automatic control system.

One good example, of isolated DC/DC converters in automation, would be to help break up ground loops. This will allow separation of parts of a circuit, sensitive to noise, from the source of that such noise. A regulated and isolated DC/DC converter can help minimize electrical noise using that isolation. The choice of an isolated and regulated DC/DC converter, for voltage conversion, will enable prevention of electrical noise isolation, as well as immunity to line surges and dropout/dips.

Internet of Things (IoT) and the Industrial Internet of Things (IIoT)

Basically, the IoT is consumer-oriented while the IIoT, a subset of the IoT, is industrial-oriented.

The IoT and the IIoT are systems of inter-related connected objects, connected on the Internet, which makes it possible to collect, share and transfer data over wireless networks with virtually no human intervention. These two incredible systems feature: distributed intelligence, countless interconnected sensors and actuators along with decentralized control.

The IIoT is made up of devices which collect large amounts of data vs. IoT devices which will generate a relatively lower volume of data. An IIoT example is a single turbine compressor blade that can generate greater than 500 Gb of data daily.

Both the IoT and the IIoT are not only about connected devices, but also regarding the information those devices can collect. Useful insights can be gained from such information.

Rugged, Isolated DC/DC converters are typically needed to power IIoT sensors such as those monitoring the condition of industrial machines. Large power surges may occur with the starting and stopping of heavy machinery; Isolated DC/DC converters with high isolation, in the order of 3 to 4 kV, are necessary here especially in protecting sensors.

The IoT and the IIoT both create smart spaces, environments/objects via the use of sensors which can communicate to gain intelligence.

Some IoT examples can be in a business office setting in which area lighting will have smart capabilities to adjust to ambient light levels, and even to the number of people present. Within the IoT, various machines are able to monitor their own functionality, or in homes which adapt to daily routines. The IoT will automatically save energy while providing human comfort.

The IoT also needs power designers that will choose cost effective and good power density DC/DC power supply modules. Applications in this space include Smart Offices, that are filled with many intelligent sensor nodes. Energy harvesting is another excellent application which uses DC/DC converters.

Power supplies for the IoT and the IIoT will need to be very efficient, at low and full load levels. DC/DC power supplies, that are designed to handle fast transient and dynamic load currents, will be best suited for these kinds of environments. Such power supplies have to have physically compact features, be reliable and, need to be cost-effective. These DC/DC power supplies will be as ubiquitous as are the sensors, processors, radios and actuators which they are designed to power.

See this video entitled “What is the ‘Internet of Things.”

Industrial Power

Industrial High Power DC/DC Converters

In industrial applications, with fork-lift trucks and other materials handling equipment, these applications use traction batteries rated from 320V to 600V. There is a series of on-board power supplies which can optionally generate 24V or 48V from the high voltage battery with a rating 4kW with high efficiency. 19“ rack product versions can be baseplate- or liquid-cooled.

Electric Vehicles (EV)

Electric Vehicle charging stations

In this present world of ever-decreasing availability of fossil fuels, electric vehicles (EVs) have greatly grown in their usefulness as a solution to reduce fossil fuel dependence which will help sustain our natural resources.

One of the prime features in EV development is their growth of battery capacity, lower charging time, greater lifespan and improved power density.

Electric Vehicles are vastly increasing in numbers on our roads. These vehicles (cars, buses, trucks, etc.) will need more charging stations, which are fast being deployed along major roads and highways as well as in local areas.

EV charging stations power levels are fast reaching several kW of power. DC/DC converters with increased isolation, with high insulation strength, are a critical part of EV charging stations.

The types of DC/DC converters which can be typically designed into chargers for electric vehicles.

The EV charging designs typically employ isolated DC/DC converters with power isolation. Converters exist that are cost effective and can be in a SIP package with 1kVDC isolation. The isolation will help to reduces EMI.

This type of DC/DC can be soldered into a PC card in the same way as any integrated circuit (IC). These converters have a 5VDC input and a regulated 5VDC output voltage which is short-circuit-proof. Their power is at 1W. These devices have a temperature range of -40oC to +85oC. The application for this DC/DC converter in EV charging is for regulated power in the network interface area of the EV charger. This part enables communication between the EV devices and the Internet.

Railway

A key area application, for industrial high power DC/DC converters, is in railway applications. This sector has applications for railway rolling stock, on-board and trackside application, industrial applications, high voltage battery-powered applications, and distributed power supply architectures.

DC/DC converters are typically used in railway environments for converting DC battery voltages to a lower voltage for use in a plethora of control and energy circuitry. Railway rolling stock designs have a DC power distribution system that employs batteries which will be deployed to maintain electrical power in case of generator failures.

DC/DC converters, for railway use, have to be constructed in accordance to EN 50155 to ensure that harsh environmental conditions do not affect their proper operation. Potential harsh conditions of heat, frost, vibration, and mechanical impact may cause serious damage to electronic assemblies. DC/DC converters used in railway technology are exposed to extremely tough conditions and must work properly and reliably for their entire service life.

Engineers are seeking DC/DC converters that can withstand these potentially catastrophic conditions, as well as being certified for railway applications.

1.2kW, 3.5kW, and 4kW DC/DC converters have flexible input/output voltage levels and have railway application approvals. This series is also suitable for general industrial use, with five DC input ranges available covering 16.8V to 170V and three DC output variants, nominal 24V, 48V and 110V.

High Power Density

The power density of a DC/DC converter is a measure of the amount of output power divided by the volume of the DC/DC converter. This is measured in ‘watts of output power per cubic centimeter’. A high value provides an advantage to the designer, allowing more power for a given volume.

Power in small packages: 3D power packaging for low power DC/DC converters

Low power, non-isolated DC/DC switching regulators are cost-effective solutions which maintain increasing demands for better performance with improved power density. Their packages need to be small so that they can compete with discrete designs. Non-isolated DC/DC designs are challenged to be highly efficient with a small sized design. The use of faster switching techniques, such as in wide bandgap designs, will help reduce size while maintaining a good efficiency.

RECOM achieves high power density with an over-molded ‘flip-chip-on-lead frame’ construction. EMI is reduced due to smaller switching current loops in the design.

See the YouTube video to increase power density with 3D Power Packaging: ‘Big power in small packages’

High power density DC/DC Converters for Industrial and Electro-Mobility Applications

The RP and RPA series are board-mounted DC/DC converters with a power rating of 30W to 240W and a high power density up to 4.5W/cm3. This is one of the highest power densities currently available on the market for this class of DC/DC power.

One of the main reasons these power devices reach such an excellent power density is by the use of planar transformers in their design which reduces the overall package size without compromising efficiency or output power. This construction method supports a fully automated production process which leads to high reliability and excellent cost-effectiveness.

These two series are best for space-constrained industrial, test-and-measurement, transport, railway and other demanding applications that require a 4:1 input voltage range and even an excellent 10:1 input voltage range.

Medical

Medical applications have a high-risk nature. Electronic equipment, especially with power electronic devices, must have very high standards of safety and reliability. Medical power supplies will need to have properties which have to meet the necessary standards for medical use in hospitals and other medical environments.

Medical grade DC/DC converters need reinforced isolation with two means of patient protection (2 x MOPP), low leakage, and a greater than 8mm creepage/clearance distance. Reinforced isolation can provide an added level of safety beyond standard isolation in order to be able to meet with the medical safety standard ES/IEC/EN 60601-1 3rd Ed.

Essentially, high isolation and low noise are critical to medical grade DC/DC converters. There is always a human, patient or operator, involved with equipment containing such devices and need to be protected in the case that a fault occurs.

High-grade medical DC/DC converters

These kinds of converters will be safe for humans directly in contact with a person. Such converters will meet either type BF (Electrically connected to patient but not directly to heart) or CF (Electrically connected to the heart of the patient) environments. These converters are able to be used in incubators, ultrasonic devices or defibrillators. These power supplies are 2MOPP (Means of Patient Protection); meeting this spec goes back to the high isolation and a robust insulation capability. The internal transformers have a reinforced insulation and will also limit the amount of leakage current that makes its way to the patient.

Some medical grade DC/DC converters are regulated and will have a 250VAC working voltage. Additional specifications can meet a 5k to 10kVAC/one minute reinforced isolation and also have low leakage currents in the region of 2µA. There may be additional options which are able to reduce standby power to milliwatt levels.

There is a 1W converter in a very compact SIP-7 package which is the smallest, complete medical supply on the market today.

There are mid-power ranges as well. These DC/DC converters are low-cost 5, 3.5, and 6W converters. These power supplies have SMD or thru-hole options. These options are 3.3V, 5V, 9V, 12V, 15V, or 24V options. There is also a 2:1 wide input voltage range.

Cost-effective medical DC/DC converters

These DC/DC converters have reinforced 250VAC continuous working isolation with greater than 8mm creepage/clearance and are providing 2 x MOPP. They also come with an extended reinforced isolation, of up to 8kVDC, that is suitable for high voltage applications.

These converters have all key the features required for critical medical applications, while keeping the cost of these modular solutions down. They are available with pins as well as surface mount devices.

DC/DC converter selection considerations

Isolated DC/DC converters can have these advantages:
  1. Isolating the grounding between input and output means that the grounding scheme of the DC source can be different from the load on the output
  2. Designers will be able to “map” a large range of different levels of DC voltage on the input relative to the output
  3. If they have very low capacitance on their output, they will more readily and safely allow multiple, isolated DC/DC converters to be placed in parallel on the same DC bus
Non-isolated DC/DC converters have this advantage:
  1. Their DC input and output are connected to the same potential. These types of DC/DC converters are Buck, Boost or Buck-Boost.

Bi-directional DC/DC converters

A bidirectional DC/DC converter is a relatively new architecture in many new applications, including automotive, server and renewable-energy systems. Low-voltage bidirectional DC/DC converters are typically non-isolated.

Three key applications for Bi-directional DC/DC converters are automotive, server and renewable-energy systems.

A basic AC/DC converter overview



Figure 4: An example of an unregulated basic AC/DC converter power supply (Image from Reference 2)


The transformer in Figure 4 has two primary windings of 115V which are shown connected in parallel or series via the input voltage selector switch. The two series-wired 6V secondary windings lead to a nominal 12VAC output which becomes rectified by the bridge rectifier BR and then DC-smoothed by the output capacitor, C. This gives a typical output voltage of about 14VDC. The full-bridge rectifier uses a four-diode typical configuration.

AC/DC Converter applications

There are many key applications for AC/DC converters and in this section, the primary application areas for AC/DC converters will be discussed.

Medical

When electronic devices do not come into direct contact with the patient and are only handled by trained operators they are classified in category Means of Operator Protection (MOOP), which means they typically only need to meet 60950-1 and 62368-1 ITE standards for Laboratory Environment Compliance.

Medical electronic designs use a Means of Patient Protection (MOPP), an electrical safety standard set forward by standards organizations across the globe; these are the American National Standards Institute (ANSI), Canadian Standards Association, and European Commission in IEC60601-1. MOPP safety standards set basic the safety requirements for medical electrical equipment.

Medical applications for AC/DC power supplies with 2 x Means of Patient Protection (MOPP) safety approval for mains-powered medical applications. The highest level of safety protection comes from using 2 x MOPP. Note that some power supply manufacturers typically highlight power supplies as meeting medical approvals whether the unit has 1 MOPP or 2 MOPP.

These compact medical grade power supplies have a universal AC input voltage range, 4kVAC isolation, low standby power consumption, active PFC (> 0.95) and do not require a minimum load.

See this podcast for more details

Automation

Automation is technology which uses sensors, actuators, and feedback techniques which can function without continuous control. An isolated local power supply is part of the power architecture that will supply the sensor/feedback/actuator control system.

Automation technology power supplies are those devices and modules that are required to supply AC/DC power to sensors, evaluation units and actuators with electrical power. Voltage that is supplied, from normal energy networks, is converted to the proper voltage and power that needs to be applied to sensor and actuator devices in order to ensure their important operation in a system.

These power supplies are usually isolated so that interference from cross-interference, ground loops, and potential differences, will not interfere with the automatic control system.

Internet of Things (IoT) and the Industrial Internet of Things (IIoT)

The IIoT is a subset of the IoT. This is because they both share common technologies such as sensors, connectivity, cloud platforms, as well as analytics.

The IoT enables a distributed intelligence, with multiple/interconnected sensors and actuators with decentralized control. Sensors are part of designated spaces, environments or objects that become “smart” via the addition of intelligent sensors that are able to communicate.

In order to power the IoT, designers use high efficiency AC/DC power supplies with low standby power consumption. Application areas include Smart Offices, with many intelligent sensor nodes, as well as energy harvesting.

Let’s take a look at the requirements for a mains-powered AC/DC supply for IoT applications.

The AC/DC supply needs to be low power, since only a few watts will typically be needed. The supply should be small, to meet the tight space constraints of IoT sensors which are compact. The AC/DC supply should also be able to handle a wide variation in load current, because the IoT node will periodically switch from active to sleep mode.

The AC/DC converter needs to have the important feature of a very low, no-load power consumption. These AC/DC converters will also need requirements for worldwide certification, in order to power systems in a domestic and foreign, commercial and industrial, environment. These power supplies need to be quite cost effective since there are needs for a great number of supplies in so many worldwide designs. See this video entitled “What is the ‘Internet of Things.”

Home Automation, Smart Homes, and Smart Office

Intelligently networked smart homes and smart offices will require control systems with a large number of low power nodes, actuators and sensors which will typically be “always on”. Cost effective AC/DC power supplies for home automation need to be able to power smart building infrastructures 24/7 with very low standby power consumption (such as just tens of mW). These AC/DC supplies must also have an extra-wide input voltage range and full household (IEC/EN60335-1), CE (LVD+EMC+RoHS2) and industrial safety certifications (IEC/EN/UL60950).

AC/DC power supplies, in Home Automation, Smart Homes, and Smart Offices, will need to have compact sizes so that assembly techniques can easy install on- or off-the power board. These supplies must also be able to deliver local DC power with reinforced isolation that will be reliable, regulated, short-circuit proof and overload-protected for the powering of smart home automation applications.

Designers can use 1 to 20W converters for versatile installation options and 3 to 30W converters which will have to fit into standard recessed wall boxes.

These AC/DC converters also need to have low standby power consumption: down to 35mW (this is below European Commission ErP Ecodesign directive limits)

Industrial Automation

Industrial AC/DC Power Converters are often used for battery charging.

Three-phase AC input battery chargers typically have ratings at 3.2kW (RMOC3200 series with DC inputs up to 800V) and 5kW (RMOC5000 series) must be able to be cascaded up to 20kW. Both of these series have outputs for 24/36/48/72/96/110 V nominal.

The SD2800 series, operates at nominal 44V or 24V three-phase AC input and provides 28V or 14V respectively at 2.8kW and 1.4kW

The SAB10000 series provides 10kW of battery charging from three-phase AC (20VDC output) or 600VDC nominal input (24VDC output) but is also bi-directional so that battery charge can be returned to the AC.

Modular, stand-alone power factor correction ‘front ends’ are available at 800W, 1600W and 3200W (single phase AC input) and at 4kW (three-phase AC input). These products are available in 19“ rack, open frame or chassis formats, or to customer specification.

High Power Density

Power density is a measure of power output per unit volume. This is important in a power supply, especially in a space-restricted area.

Efficiency is a prime issue in power electronics. Improving efficiency in power supplies will improve power density. One sure way to increase power density is to reduce component sizes. Designers should choose the smallest possible capacitors, inductors, transformers and heat sinks that will meet design needs.

Applications that require the highest efficiency, (in the order of 99%) and high power density (73 W/in3), are high-end servers and telecom. AC/DC converters are used in such an applications.

Industrial

Modern industry demands decreasing size, footprint, with solid power density numbers than AC/DC predecessors. Modern advances in switching controllers, topologies and components enable AC/DC power supplies to have 2X the power density than in previously designed converters. New designs must improve upon safety, reliability, efficiency, and performance in order to be competitive.

Designers must know how much input AC input voltage swing their selected AC/DC converter will be handling in their design. In most industry in the Western hemisphere, the output from the AC mains range from a nominal 100 VAC up to 277 VAC for use around the globe.

It is critical that the AC/DC converter function efficiently over the entire load range from full load down to light load, and even to no-load conditions.

Most AC/DC converters are internationally safety certified to UL/IEC/EN standards, with Certification Body (CB) Reports. Saving energy is critical to customers and many applications switch automatically into standby in order to reduce power consumption.

Test & Measurement

In the Test & Measurement sector, devices can span from desktop products to server rack installations. Such systems need AC input voltages which can span a nominal 90VAC to 277VAC, and often times higher for some industrial applications.

Low power, PCB mounted AC/DC converters, range from 3W to 20W are frequently designed into these systems. If higher power is needed, such as from 40W to 550W, designers may choose chassis-mounted options.

Operating without a fan environment is often challenging in a Test & Measurement environment. All selected AC/DC converter solutions for this environment must be able to provide useful power at high temperatures without the benefit of forced air.

230W and 550W products are available with the addition of baseplate cooling.

Safety certifications for different end-application environments are available according to IEC/EN 61010, IEC/EN 62368, IEC/EN 60601, EN 60335 requirements.

Good AC/DC converters will need to meet ElectroMagnetic Compatibility (EMC) standards without the use of any added components. All AC/DC devices will need to have low mains leakage current that is critical in Test & Measurement applications, and in particular in medical environments. Applications that require sensitive measurements, will need low output noise AC/DC power supplies which is a significant benefit to designers in many Test & Measurement systems.

Mobility and e-Mobility

AC/DC converters are able to provide power to electronic devices that require a conversion process from AC to DC. In this section we will discuss applications for AC/DC converters in both Mobility and e-Mobility.

Mobile vs. Mobility: The term ‘mobile’ is regarding mobile technology and devices, which are essentially the ‘nuts and bolts’ that enable mobility. Mobility is an umbrella for mobile and ensures whether or not everything within the nuts and bolts will work well together.

e-Mobility

e-Mobility includes such typical applications include electric vehicles (EV), all types of scooters which are so popular in today’s market, and similar other small vehicles. These devices need battery chargers as well as on-board power converters for device motor drives and any auxiliary equipment.

In order to be successful in replacing gasoline engine vehicles with electric power, a larger network of charging stations and outlets will be needed. An example for faster deployment of charging stations is that there exist only approximately 113,600 charging outlets in the United States today for plug-in electric vehicles along U.S. roadways and 36% of them are in the state of California.

There is a present effort to build much faster chargers to lower existing charging times to under 20 minutes.

In more complex products there is the need to have added features like battery conditioning and bi-directional converters for energy balancing. A solid performance range of suitable AC/DC converters is necessary for these kinds of applications.

Battery conditioners (computerized devices that charge, maintain, and prevent sulfation from occurring in lead batteries), along with power factor ‘front ends’, will reduce harmonic distortion (for example from 45% to 5%) and significantly improve system power factor performance. Power factor is basically a measure of how efficiently the electrical power is being used to perform useful work.

AC/DC e-Mobility applications need to be rugged, reliable with long lifetimes, have broad environmental capability with sealed and weatherproof options, power factor correction (PFC), battery charging/conditioning capability, and 20kW+ rating.

High power AC/DC converters can be used for Special Applications. One typical example is an AC/DC converter capable of operating at nominal 44V or 24V three-phase AC input while providing a 28V or 14V capability at either 2.8kW and 1.4kW.

Other AC/DC devices are battery chargers/conditioners specially designed for the E-mobility market which is categorized by battery voltages of less than 24V, 24V, 36V, 48V, and even greater than 48V. The 24V segment typically accounts for more than 25% of the electric mobility revenue share. These AC/DC converters are rated at 2kW and 1kW respectively, with excellent wide output operating voltage ranges to enable designers with flexible applications.

Some AC/DC converters in this segment will have modular stand-alone power factor correction ‘front ends’ are also available rated at 800W, 1600W and 3200W (single phase AC input) and at 4kW (three-phase AC input). Some of these AC/DC solutions fit into designs in 19“ rack, open frame or chassis formats.

Other key applications, for these types of AC/DC converters, in e-Mobility, are Electric Vehicles and Electric Vehicle charging systems, with the addition of Railway and Transportation as well.

Mobility

The term ‘Mobility’ refers to Electric Vehicles (EVs), disability scooters, and other small mobile vehicles. These vehicles need battery chargers as well as on-board power management to drive motors and auxiliary equipment.

The key features of AC/DC converters in this sector are ruggedness, long lifetime, high reliability, fairly extreme environmental requirements, weatherproofing and sealing of AC/DC power solutions, Power Factor Correction (PFC), and power ratings up to and exceeding 20kW.

In this area, battery conditioning and conditioning, bi-directional power converters employed for energy balancing. Power Factor Front Ends are also a part of Mobility.

There are also working platform power designs, for Mobility applications, that may be adapted to customer specifications for new and custom designs.

Fakes vs originals

Counterfeit power supply components can wreak havoc in the design arena. These devices can malfunction or not even function at all. If they do function, they can still be a danger to injure people or even cause a fire. These will severely hurt a supplier’s reputation.

The importance of the right partner

It is highly recommended that buyers purchase known manufacturer products from their global distributors.

Savvy designers and purchasing people know that acquiring electronic components and power supplies, from trusted distributors, and manufacturers will be the best route to ensure a fully functional, reliable, and safe end design.

References