How Does Residual Current Detection Help Improve the Competitiveness of EV Charging Stations?
CONTENTS
What type of Residual Current Device (RCD) you should use for protection?
Why to choose Mornsun Type A + Smooth DC of 6mA Residual Current Transducer
In recent years, the field of new energy vehicles has thrived. According to Statista Market Insights, the revenue of electric vehicle market is projected to reach $561.3 billion by 2023, and expected to hit an annual growth rate of 10.07% (CAGR 2023-2028). The rapid growth of the new energy vehicles industry has led to an increased demand for electric vehicle (EV) charging stations. As manufacturers strive to enhance their competitiveness in this evolving market, one innovation that has emerged is Type A + Smooth DC of 6mA Residual Current Detection.
How Does Residual Current Generate During EV Charging？
During the charging process of an EV, the On-Board Charging System (OBC) plays a crucial role in converting AC power from the grid into DC power for charging the vehicle's battery pack. However, there is a potential risk of current leakage or earth default, which can lead to serious consequences such as electrocution, electrical fires, or damage to vehicle components. Therefore, it is imperative to detect and protect against these residual currents.
The diagram below illustrates a typical electrical configuration of an On-Board Charging System (OBC), comprising an EMI filter on the input side, AC/DC rectifier, PFC circuitry, DC/DC power converter, and an EMI filter on the output side. Over time and due to vibrations and aging effects inherent in electric vehicle usage, insulation failure of the OBC can occur.
Diagram of On-Board Charging System (OBC)
Depending on the fault location, different types of residual currents are generated in the EV charging system:
① A ground fault on the AC input side of the grid, resulting in sinusoidal AC residual current at grid frequency.
② A ground fault in the AC/DC rectifier section of the OBC, resulting in pulsating DC residual current.
③ A ground fault occurring in the DC/DC converter modules of the OBC, producing smooth DC residual current.
Therefore, it is essential to detect sinusoidal AC residual current, pulsating DC residual current, and smooth DC residual current throughout the entire EV charging system for protection in electrical installations and prevention against electric shock hazards to human body. With advancements in charging pile technology, relevant IEC standards have established specific requirements for residual current devices (RCDs) to ensure adequate protection during EV charging.
What type of Residual Current Device (RCD) you should use for protection?
The selection of the appropriate Residual Current Device (RCD) for protection depends on the specific requirements. An RCD is designed to detect earth fault currents and interrupt the power supply in case of an earth current flow. It primarily serves to safeguard electrical circuits and human body against electric shock and electrical fire risk.
Various types of RCDs are available, each capable of detecting different types of residual currents. According to the international standard IEC 60755, four types of RCDs are defined for AC applications: Type AC, Type A, Type F and Type B.
Residual Current Device (RCD) types and the residual currents types that they can detect
The Type AC RCD is designed specifically for detecting sinusoidal AC residual currents, which restricts its usage to basic devices that do not generate smooth DC residual currents. These RCDs are commonly used for general purposes applications such as household appliances, like incandescent lamps and water heaters.
Type A RCDs are capable of detecting sinusoidal residual currents detected by Type AC RCDs. They are intended to detect sinusoidal AC, pulsating DC residual current and pulsating DC residual current superimposed with smooth DC residual current up to 6 mA, making them suitable for residential and commercial building applications, such as induction cookers, microwave ovens, dishwashers, and computers of all types.
Type F RCDs are used in cases where the application may generate composite residual current. They can withstand smooth DC residual current of up to 10 mA superimposed on the residual current. Additionally, a Type F RCD is also able to detect all the residual currents detected by a Type A RCD. Such devices are commonly utilized for protection in applications like single-phase heat pumps, variable-frequency air conditioners, swimming pool pumps or washing machines.
The international standard IEC 61581-1 provides two options for smooth DC residual current protection devices in charging stations: either a Type B RCD or a Type A + DC 6mA RCD with appropriate equipment to disconnect the supply in case of DC fault current exceeds 6 mA.
Requirements for Residual Current Devices in EV Charging
For AC and DC charging stations, different EV charging modes have specific requirements for residual current devices (RCDs). According to the industrial standards of EV charging, we outline the specific requirements as below.
Requirements for RCDs in different EV charging modes
For charging modes 2 (IC-CPD), the IEC 62752 standard specifies that In-Cable Control and Protection Devices (IC-CPDs) should ensure tripping for residual sinusoidal AC, residual pulsating DC, and smooth residual DC exceeding 6 mA, whether suddenly applied or slowly rising. Similarly, for charging mode 3 (RDC-DD), the IEC 62955 standard defines that Residual Direct Current - Detecting Devices (RDC-DDs) are designed to remove or initiate removal of the supply to the EV in cases where a smooth residual DC equal to or above 6 mA is detected. Pluggable EV DC charging stations in mode 4 should be compatible with Type A RCDs, equipped with a RCD, moreover, may also have an overcurrent protection device.
Typically, Type B RCD are more costly, so many EV charging station manufacturers choose to use a Type A RCD + Smooth DC of 6mA solution to meet the standard requirements.
Why to choose Mornsun Type A + Smooth DC of 6mA Residual Current Transducer
As a leading power supply manufacturer and innovator, Mornsun is dedicated to providing one-stop power supply solutions for various industries, including Type A + Smooth DC of 6mA residual current transducer TLB6-A1 series for EV charging. This solution can flexibly match different application scenarios, improving system stability and security while reducing costs. Now let's explore the advantages and highlights of Mornsun TLB6-A1 series.
A Wide Range of Applications
Mornsun TLB6-A1 series offers compact size and multiple package designs, meeting various board layout and installation requirements for both single-phase and three-phase inputs. This flexibility allows it to cater to different application scenarios and provide comprehensive protection.
Meet different installation needs with various packages
High Performance
The Type A + Smooth DC of 6mA residual current detection solution for EV charging provides comprehensive and consistent protection against various leakage currents, surpassing conventional Type A and Type AC solutions. Compared to other modules, Mornsun RCD module TLB6-A1 series stands out with its integrated IC that has independent intellectual property rights, offering the following advantages:
1) Complete protection functions including overvoltage protection, start-up shield, and magnetic saturation protection.
2) Excellent performance in trigger threshold, time consistency, and stability with minimal batch differences.
3) Innovative dual threshold detection and current waveform identification algorithm for accurate and fast identification of residual currents.
4) EMC protection design to prevent system from refusing to break when a leakage fault is generated or malfunction when no fault occurs.
5) One key calibration function to eliminate the influence of small leakage currents generated by environmental factors or system parasitic parameters on real leakage currents.
High Security
Mornsun Type A + Smooth DC of 6mA residual current transducer TLB6-A1 series meets the IEC61851, IEC 62752 and IEC 62955 standards, allowing it to easily detect DC, AC, and various pulsating residual currents with high response speed and excellent accuracy.
With its autonomous magnetic recovery technology, the TLB6-A1 series has a surge current capability of up to 3,000 A. It operates stably in harsh environments due to its strong resistance to electromagnetic interference and complete protection function. These modules are widely used for current detection in industries such as EV charging, low voltage equipment, photovoltaic systems, etc., thanks to their advantageous features and wide temperature range (-40℃ to +85℃).
Cost-effectiveness
With an in-house production of key components, a strong R&D team, stable supply chain, sufficient production capacity and advanced production management system, Mornsun ensures consistent high reliability in mass production while guaranteeing fast delivery and cost-saving for customers.
Conclusion
With the growing demand for EV charging stations, manufacturers face a real challenge to differentiate themselves. However, Mornsun's optimal residual current Transducer can help you overcome the limitations of current detection requirements and enhance the competitiveness of your EV charging system. They provide complete protection while reducing design and maintenance costs. If you need a specific RCD solution for your projects, Mornsun is definitely an excellent choice. We also offer test equipment or simple test boards for performance verification. Additionally, we provide other smart control modules such as small-size high-performance current transducers, contactor control modules and DC contactors to meet various current detection needs.
Ready to choose a residual current sensor that fits your applications and aligns with your business goals? Feel free to contact us, we guarantee that we have the optimal solution tailored to your needs!
