As people all over the world pay attention to global warming, governments all over the world have actively promoted the rapid development of new energy vehicles. the sales volume of new energy vehicles in Europe increased by 52% year-on-year to 403300 vehicles In 2021. It is estimated that by 2030, the proportion of new energy vehicle sales is expected to increase significantly to 20%.
Looking at the plans of European countries to ban fuel vehicles, we can find that Europe is accelerating the replacement of new energy vehicles. In 2020, British Prime Minister Boris Johnson announced that the sale of new gasoline and diesel vehicles in Britain would be banned from 2030, and the deadline would be advanced by another five years; The German federal government passed a bill in 2016 to ban the sale of fuel locomotives in 2030, and it plans to have 10million electric vehicles on the road in Germany by 2030; In 2016, the Netherlands passed a proposal to ban the sale of gasoline / diesel passenger vehicles in 2030; Norway has made it clear in the 2016 national plan that the sale of gasoline / diesel vehicles will be completely banned in 2025; France, Israel, Spain and other countries have announced plans to phase out fuel vehicles between 2030 and 2040.
It can be seen that new energy vehicles, especially pure electric vehicles, will be the main trend of automobile development in the future.
With the rapid development of new energy vehicles, the demand for electric vehicle charging equipment has also increased sharply. As an IC-CPD (in cable control and protection device) equipped with electric vehicles, its demand is also rising rapidly. With the vigorous development of the electric vehicle industry, the performance of IC-CPD products belonging to the distribution accessories of electric vehicles plays an important role in the protection of vehicle and personal safety.
In the IEC 61851.1-2010, it is clearly specified that residual current protection in AC charging equipment shall adopt type B or type a +6ma smooth DC RCD. At the same time, it is clearly stated in the relevant IC-CPD standard iec62752-2018 that the residual current protection device shall detect smooth DC 6mA.
Fig 1. Requirements for leakage protection in iec61851.1
Fig 2.Requirements for residual current protection in 5.2.8 of IEC 62752-2018
For the U.S. market, although the U.S. government has not mandated manufacturers to implement the standard ul2231-1-2011, the standard also mentions the protection requirements for A DC residual current. Ul2231 describes that ICCID is divided into CCID5 and CCID20 protection types, which are selected according to actual needs. The protection threshold required in ccid5 is 5 ± 1mA AC/30ma DC
Fig 3.Requirements for residual current protection in 21.2 of UL 2231-2-2011
Why are there clear requirements in IEC 61851.1, IEC 62752 and UL 2231-2 that residual current protection devices are required to detect DC leakage?
let’s understand the definition of residual current type:
1) Type AC: it cannot be detected in the environment with smooth DC leakage
2) Type A: it can only work in the environment with smooth DC leakage less than 6mA
3) Type F: it can only work in the environment with smooth DC leakage less than 10mA
4) Type B: sensitive to smooth DC leakage
Conclusion: The purpose of detecting smooth DC 6mA is to ensure the accuracy of type a leakage protection.
For traditional AC or A-type leakage protection devices, the core components are mostly zero sequence mutual inductors. The principle of current measurement is mostly mutual inductance. The changing magnetic field is changed by the changing electric field, and then the changing current is induced by the changing magnetic field, and then the current value is calculated through back-end processing. However, when smooth DC leakage is superimposed in the power environment, the situation will change.
Fig 4.Influence of DC fault current on type a detection fault current
According to figure 4, we can analyze the traditional Type A leakage protection device:
Generally speaking, for the magnetic ring used for current detection, its B-H curve is shown as an S-shaped curve passing through the origin, with linear and nonlinear regions.
When the sensor detects fault AC normally, its corresponding electric field intensity curve a will be in the linear region of the curve, and the induced magnetic field intensity curve is B.
When the DC residual current is superimposed on the power frequency AC, the superimposed DC will generate a fixed electric field strength at the same time, which will shift the curve a to the curve C. if the electric field strength of the DC current is enough to make the induced electric field strength reach the nonlinear region, the induced magnetic field strength curve is D.
According to figure 4, it is found that the magnetic field strength of curve D is significantly less than that of curve B, and the corresponding detected fault current for leakage protection device will also be significantly less than the actual value.
This will cause that when the actual residual current reaches the rated value, the leakage protection device will not act, thus endangering people, causing damage to lines or equipment, and may cause terrible consequences such as fire in serious cases.
Nowadays, with the development of electric vehicles, the demand for IC-CPD is also developing towards miniaturization and low cost. As one of the main components of IC-CPD, leakage current detection module also needs to comply with the trend of the times. The switch value sensor integrates the dual functions of current acquisition and processing, which greatly reduces the number of electronic components and layout space on the PCB of IC-CPD; At the same time, the output mode of switching value is more convenient for IC-CPD engineers to process signals and simplify the production of IC-CPD software. Therefore, switching value products are more and more popular among IC-CPD manufacturers.
The Magtron’s switching value products meet the latest IC-CPD leakage detection requirements (IEC61851/IEC62752/UL2231)
Take the rcmu101-k series leakage current sensor of the Magtron as an example:
The series of sensors are B-type residual current sensors, which adopt switching value output to provide IC-CPD customers with easy-to-use and excellent leakage current detection solutions. The scheme adopts high-precision adaptive fluxgate sensing technology, which can realize accurate real-time and effective detection of AC and DC residual current in principle, and output tripping signal through built-in processing unit (MCU), which can fully meet the leakage protection requirements of IEC61851/IEC62752/UL2231. At the same time, the product series can fully cover the application of 3.3kw, 7KW 22kW, single-phase IC-CPD and 11kW, 22KW,three-phase IC-CPD application.
Magtron – All type Current Sensitive Residual Current monitoring Unit (RCMU Series Sensor) developed for EV-Charging Providing all-current sensitivity.
- Protects against hazardous situations with fault currents, Preserving RCCB type A from saturation in case a smooth DC component in the circuit
- Small volume and footprint for integration into compact IC-CPD and AC Charging Wall-box Charging Piles and OBC (On board Charging)
- Robust mechanical and electrical design suitable for harsh environmental conditions
- Electrical safety at low cost (compared to TYPE B RCCB)
- Integrated self-check functions
l Applications (EV Charging Mode 2 Mode 3 and OBC)
- IC-CPD in charging Cables for electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV).
- AC Charging Wall-box for EV and PHEV.
- AC Charging piles for EV and PHEV
- OBC (On board Charging) system
- TUV SUV Mark: B 1135980001
- TUV Rheinland: 505140000001
- DEKRA Attestation Of Conformity : 6097030.01
 IEC 61851.1-2010 Electric vehicle conductive charging system – Part 1: General requirements
 IEC 62752-2018 In-cable control and protection device for mode 2 charging of electric road vehicles (IC-CPD)
 UL 2231-2-2011 Personnel Protection Systems for Electric Vehicle (EV) Supply Circuits: Particular Requirements for Protection Devices for Use in Charging Systems