Key Components of EV Charging IC-CPD
With the rapid development of new energy vehicles, the demand for electric vehicle charging guns (IC-CPD) is also rising rapidly.
IC-CPD: It integrates basic functions such as power supply control, control guidance, and leakage protection. Some high-end IC-CPDs also integrate other functions such as displaying the real-time status of the charging process and temperature control. The internal circuits include switching power supply, relay, CP signal modulation, leakage protection, voltage/current detection, etc.
Introduction to the components of electric vehicle charging guns (IC-CPD)
1.1 Relay
The relay mainly plays the role of controlling the charging switch in IC-CPD and has the advantage of strong driving ability. The contact part should have an arc extinguishing circuit, and the discharge circuit of the drive coil part has double protection to increase reliability and service life. The inside of a relay is generally divided into two parts: the contact and the coil. The rated current, voltage and rated voltage of the contact are given on the nameplate of the relay. The main reference parameter on the IC-CPD board is the withstand voltage value of the relay. The voltage condition for the withstand voltage test in the IC-CPD test standard is 2KV. In addition, for the European standard CE certification, the contact spacing of the relay must be greater than 3mm.
1.2 Introduction to switching power supply chips
The main function of the switching power supply control IC is to provide the required power to each module. In the on-board charging gun (IC-CPD), it mainly provides the required voltage signal to the relay, chip, and op amp IC. The switching power supply is generally divided into two types: AC-DC and DC-DC. The AC/DC switching power supply is mainly divided into non-isolated circuits and isolated circuits. In the on-board charging gun (IC-CPD) charging gun, AC-DC mainly uses an isolated (flyback) switching power supply circuit, and most of the DC step-down is processed by an LDO module.
1.3 Current/voltage sampling device - transformer
The current/voltage transformer on the IC-CPD board mainly plays the role of current/voltage (electric quantity) sampling. In the circuit, if the voltage is too high, the switching power supply will be damaged, and if the current is too large, the relay will be damaged. The principle of voltage and current transformers is to use the principle of electromagnetic induction to convert high voltage into low voltage and large current into small current, so that the secondary side equipment (such as relays) can be miniaturized, which can not only protect the circuit, but also keep the operators away from high voltage to ensure personal safety.
1.4 Leakage current sensor
Interpretation of the leakage protection requirements of the IC-CPD standard
The national standard GB/T18487.1 stipulates that in the AC charging mode, a device that meets the residual protection function of type B or type A should be provided. At present, there is no mandatory requirement for the use of type B residual current protection devices in the current national standard, but in the future, the requirements for leakage protection of domestic IC-CPD will definitely become more and more stringent.
The European standard IEC61851-1:2017 stipulates the requirements for IC-CPD, requiring that the residual current protection in AC charging equipment must use a B-type or A-type + 6mA smooth DC RCD. The IEC62752-2018 standard for on-board charging guns (IC-CPD) also mentions that the residual current protection device must be able to detect a smooth DC of 6mA. Compared with the requirements of the national standard, the European standard has higher requirements.
IVY Metering has launched products that meet the latest IC-CPD leakage current detection requirements. This series of products is a B-type leakage current sensor that can detect different leakage components and fully meet the leakage protection requirements of IEC62752&IEC62955. The product can fully cover the application scenarios of 3.3kW, 7kW single-phase IC-CPD/Wallbox and 22kW three-phase IC-CPD/Wallbox. IVY's leakage current sensors comply with European and American standards. Compared with traditional leakage current sensors, it is more reliable, more sensitive and safer.
