Modules for battery charging applications

Electric vehicles and e-mobility in general, are the future of transportation in a world that needs to reduce its carbon footprint. To make battery-powered vehicles cost-effective, electric vehicle chargers must be as efficient and economical as possible. While power conversion stages at the multi kW level are improving with the latest topologies and semiconductor technologies, AC/DC auxiliary supplies must also match the EV charger requirements in terms of efficiency and value.

Charging wall boxes and charging stations are often installed in overvoltage category three (OVC III) environments with the potential for significant dips, surges and transients from lightning strikes, which the power supplies must also withstand. Additionally, temperature variations can be extreme, and the AC supply voltage available may be three-phase 480VAC or 277VAC. Moreover, auxiliary AC/DC modules must operate reliably in this environment along with switching regulators and DC/DC converters that provide internal voltage conversion and isolation.

These series of 3W to 60W AC/DC converter modules have 85–528VAC input for the line to neutral connections in 100/115/230/277VAC single-phase systems or a line-to-line connection in a 400/480VAC system. The cost-effective and fully certified parts are available with a selection of outputs; they feature a wide operating temperature range of -40 to +85°C for harsh environments and are ideal for auxiliary supplies in battery charging and monitoring systems. These series comply with EMC standards without external filters and have low, no-load and standby consumption.

A selection of the RACxx products is suitable for direct connection to OVC III systems. The RAC03E-K/277, RAC04NE-K/277, RAC10-K/277, RAC20NE-K/277, RAC20E-K/277, RACM60-K are designed as auxiliary internal power supplies for EV charging systems. They are EN IEC 61558-2-16, EN IEC 61558-1 and EN IEC 60335-1 certified with a wide input voltage range of 85-305VAC to ensure a stable output voltage even if the input voltage is not stable.

Suitable for both line-to-phase or line-to-line connections in 277/480VAC systems, the fully-certified RECOM RACxx-K/480 series AC/DC converter module provides an isolated 5W, 15W or 25W output at 5, 12, 15 or 24VDC from a supply voltage ranging from 85 to 528VAC. The parts are EMC compliant (Class B) without external components, and the operating temperature range is -40 to +80°C. They are suitable for direct connection to OVC III systems, which makes it ideal for auxiliary converters in outdoor battery charging stations as well as general industrial use.

The RACPRO1-Txxx series are compact three phase DIN rail mounting power supplies suitable for demanding battery charging applications in harsh environments with an extended mains input surge immunity, reinforced isolation and robust internal EMC filters for a long operational lifetime. The input can be 3AC mains (3P + E) or 450-850VDC. The 480W and 960W versions additionally feature a charging mode switch for direct charging of 24V or 48V batteries in low voltage electric vehicle applications such as golf carts, people movers or automated guided vehicles (AGVs).

Circuitry in battery charging applications often requires DC/DC converters to produce auxiliary rails and isolated power for communication interfaces. High-efficiency board-mounted products such as the 4:1 input 40W RP40 series and the 20W REC20 series feature six-sided shielding in 2”x1” packages, which are ideal for providing control circuitry power in charging stations and battery management systems.

For lower power battery management applications, there is the 4:1 input 8-watt RP08 series, which includes parts with an input range of 160V and is suitable for strings of batteries. When a low-power 5V isolated rail is required, perhaps to provide a -5V supply for analog circuitry or for an isolated interface in a smart EV charger, the RFMM-0505 or RKE series converters are suitable; they feature 1W output, 4kV isolation, and comprehensive safety certifications.

Non-isolated switching regulators provide high-efficiency replacements for linear regulators in battery charging systems. The R-78E-1.0 series, for instance, peaks at 97% efficiency, with 1-amp output current from 3.3V, 5V, or 12V outputs and input ranges up to 28V. For output power up to 3kW, the half-brick RBBA3000-50 product is a buck-boost converter, which has an input range of 9–60V and an output of 0–60V that can be preset; this can be above or below the input voltage. Its typical applications include 48V to 24V or 12V to 24V battery power conversion in electric vehicles and battery voltage stabilizers in charging stations for UAVs and drones.

RECOM’s sister company, PCS, specializes in high-specification, custom power supply solutions, including battery chargers, balancers and conditioners for mobile and stationary applications. PCS products are based on successful platform designs developed for demanding environments up to defense-grade conditions. The inputs can be single- or three-phase, and the outputs can be customer-specified to 20kW or more. Bidirectional designs are available for energy recovery applications. All products provide full protection, monitoring and control through intelligent interfaces.