CET designs a high power common mode choke
CET Technology, a leading supplier of standard and custom magnetics, has been contracted to design and build a high power common mode choke for Electric Vehicle Charging Stations (EVCS). With the growth in popularity of battery-powered electric vehicles amongst consumers and commercial and municipal fleets, there is an escalating need for widely distributed publicly accessible charging stations. The need to support faster charging at higher voltages and currents than currently available continues to increase faster than demands are being met
According to Dave Hurst, Senior Research Analyst – Pike Research, “Sales of plug-in EVs will increase at a compound annual growth rate of nearly 40% over the remainder of the decade, while the overall auto market will expand by only 2% a year.” Battery capacity and the capability of handling faster charging are both increasing, and methods of charging need to change and improve.
One method is to use a Direct Current (DC) connection for recharging in as little as ten minutes. The DC currents can be substantial, 425 amps at a voltage of 750 Vdc. CET Technology has designed a high power common mode choke to filter high frequency (4kHz) while maintaining low impedance with an inductance between 100 to 250µH.
How a Common Mode Choke Works
In electronics, a choke is an inductor used to block high-frequency alternating current (AC) in an electrical circuit, while passing low-frequency or direct current (DC). The name comes from blocking—“choking”—high frequencies while passing low frequencies.
Common mode chokes are useful for the prevention of electromagnetic interference (EMI) and radio frequency interference (RFI) from power supply lines and is most often used as a filter on the input line for switching power supply circuits. They are wound on a high permeability core, most often toroidal or UU cores, with two windings. The windings are mirror wound, with one on the line side and one on the neutral side of the input AC.
Under normal operation, the current through each winding is equal and opposite. Because of the mirror winding, the magnetic fields in the core cancel out. This allows the common mode choke to present a very low impedance to the input AC line. This also means the core will not saturate even for large differential-mode currents, and the maximum current rating instead is determined by the heating effect of the winding resistance. Click the link to read the common mode choke, the basics.
About CET Technology
CET Technology specializes in the design and manufacture of standard and custom magnetics. CET manufactures a full line of ROHS compliant components including Electrical Transformers, Power Supplies, Inductors, Coils, Chokes, and DC/DC Converters. They employ the latest manufacturing techniques for lower production costs and excellent repeatability and performance.