With the rapid growth of the Electric Vehicle market, the demand of EV chargers has been increasing tremendously in these years. Based on types of electrical currents for charging, EV chargers are divided into AC chargers and DC chargers. Featured by compact size and easy installation, AC charger is generally most appropriate for residential units, workplaces and communities, to be installed in public parking lot/garages. With its high market demand, AC chargers currently are the mainstream in the market.

Generally, EV charging current power ranges from a few kilowatts up to tens of kilowatts. So safety protection is extremely critical for EV charging. Many countries have put forward corresponding safety regulations, especially on the importance to the leakage protection of EV chargers.

In electric vehicles charging, a large number of ac-dc conversion (rectifier/inverter) circuits exist. So if a leakage fault occurs, there will be not only Type AC and pulsating direct residual current but also DC residual current and smooth DC residual current generated by two-phase/three-phase rectification and filtering. Thus, being capable to detect both AC residual current and DC residual current is required for the leakage protection solution.

ZETTLER Magnetics has recently developed a series of EV-RCD module with leakage protection solution, which are suitable for Mode 2 and Mode 3 EV chargers under  European standards.

n  Leakage detect Mechanism

The Zettler EV-RCD module adopts the principle of detecting differential current by the response of specific Amorphous cores to tiny magnetic field changes. When an electrical system is working perfectly, the vectorial sum of the currents on all current-carrying conductors of a supply line is equal to zero, and thus there is no magnetic field around the supply line. If a residual current does occur and is drained outside of the supply line via an object or the ground due to an insulation fault, a differential current greater than zero will exist. 

The ZETTLER EV-RCD modules use an Amorphous core with a high remanence ratio and integrates a self-excitation oscillation circuit to generate periodic oscillation. When the differential current passes through the core, the magnetic field would change, resulting in the variation on the oscillation waveform accordingly. The ZETTLER modules will determine the differential current value and the type through the comparison of waveform variation and feedback AC and DC leakage signal correspondingly when the value exceeds the limitation of safety standard.

Compared with the traditional type A leakage protection products, the Zettler EV-RCD module has the following advantages:

l  Excellent accuracy: Detect 3-6mA DC differential current, and send response signal according to safety requirements.

l  High surge-current withstand capacity: Withstand 3000A instantaneous current surge without damage.

l  Being able to detect various current types:  Fulfill type B leakage detecting.

n  List of EV-RCD Modules

n   Application

Zettler Magnetics EV-RCD series provide options for integrated busbar or open hole and a diverse range of charging current levels to satisfy 16A, 32A, and 63A applications.

ZETTLER's magnetics R&D team constantly pursues innovation and provides customer focused solutions. If you have any requirement for magnetics components, such as transformers, power module or EV-RCD leakage protection solution etc., welcome to visit our website www.zettlercn.com or contact sales@zettlercn.com for more information and support.