The Challenges of Testing EVSE Integrated with Battery Energy Storage Systems

Feb-16-2023

Power Electronics EV Battery

As electric vehicle (EV) sales continue to grow and specifications improve, electric vehicle supply equipment (EVSE) manufacturers are increasingly developing fast charging facilities. Market research reports indicate that by 2025, the amount of public EVSE deployed globally will increase to over three million. How to integrate solar energy and energy storage systems (ESS) into charging stations, and how to shorten charging time and improve safety, have become some of the most important issues in the industry.

Currently, EV charging methods can be divided into AC and DC charging, and their applications include home, public, and commercial areas. Among these, DC fast charging is the more complex method with respect to design and installation. In addition to compliance with the industry’s charging communication protocols and standards, matters such as the rated capacity of the total power supply and the charging fee model must also be taken into consideration. EVSE products must meet various regulatory standards to meet the needs of different EVs and markets. Moreover, EVSE that offers multiple connector types also contains multiple power modules, which can be allocated according to the varying power requirements of different vehicles and dynamically adjusted as these requirements change. These new features of EVSE also pose challenges for how to quickly and completely test and verify them during production.

Chroma offers a comprehensive HPC test solution

Chroma offers a comprehensive High Power Charging (HPC) test solution by pairing the Chroma 8000 EVSE ATS with the Chroma 61800 Grid Simulator and the Chroma 17040/17040E Battery Simulator. The system can be further equipped with EV or EVSE simulators for various DC charging standards (CCS, CHAdeMO, GB/T, ChaoJi) according to user needs. Depending on the device under test (DUT), a single or multi-coupler HPC test platform can be set up to improve the quality, shorten production time and reduce production costs of high-power EV charging equipment.

The Chroma 8000 EVSE ATS comes equipped with the brand new PowerPro 5 software platform, which adds multi-threaded testing functionality. It can simultaneously simulate up to four EV standards with identical or different communication protocols from different regions. The software allows the user to control the EVSE to output multiple connectors at the same time based on the specified test conditions, and can even simulate plugging in at different times for power sharing (load management) testing. This enhances the realism of the test scenario and, compared to traditional single-coupler testing, significantly reduces the overall testing time by up to 40%, effectively expanding the testing capacity and coverage. The Chroma 61800 Grid Simulator and Chroma 17040/17040E Battery Simulator both have energy recovery functionality, which reduces power consumption and lowers environmental temperatures. This helps customers save on electricity bills and furthers energy-saving and carbon-reduction goals.

Alongside conventional AC or DC plug-in EVSE, new products and technologies such as wireless power transfer (WPT) have emerged for EV charging. WPT is safer, more convenient, and can be installed directly onto the parking space surface, avoiding safety risks caused by aging charging plugs.


▲ Chroma's customized DC high-power charging test solution

Chroma 8000 Electric Vehicle Supply Equipment ATS (EVSE ATS)

Chroma's EVSE automated test system, paired with the regenerative high-power Chroma 61800 grid simulator (up to 840kVA) and Chroma 17040 battery simulator (up to 600kW), offers a customized HPC test solution. Users can select the suitable EV or EVSE simulator for each DC charging standard (CCS, CHAdeMO, GB/T, ChaoJi) and configure the EV & EVSE 2-in-1 high-power charging test platform according to their test requirements.

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Chroma EV Wireless Power Transfer ATS Test Solution

Chroma has developed the Chroma 8000EV Wireless Power Transfer ATS Test Solution, aiming to help customers solve the tedium of costly and repetitive input-output characteristic and efficiency offset testing in the early stages of product development, and to assist manufacturers in speeding up product launches and gaining a competitive edge. This automated test system fully covers the power requirements of the SAE J2954 regulations for WPT charging and comes with dedicated testing software. The software provides real-time data monitoring and recording that can be traced and viewed, and can generate 2D/3D charts, significantly reducing testing time and manpower required during product development. The system also incorporates Foreign Object Detection (FOD) testing in compliance with the GB/T 38775 standard. By simply entering the test start/end positions and segmentation parameters, users can define the segmentation area and the number of test points on the ground assembly (GA) and calculate all the FOD test coordinates on the entire GA surface. Chroma's proprietary FOD platform makes it easy to set up and execute automated FOD tests through a sequence of simple operations, successfully identifying safety hazards caused by metal objects heated during the wireless charging process.

▲Chroma 8000 EV Wireless Power Transfer ATS
 

Chroma EV Wireless Power Transfer ATS Test Solution

Chroma WPT test solution performs interoperability, performance, and radiation emission testing of wireless inductive charging systems. Chroma provides WPT test solutions for all power classifications ranging from 3.7kVA to 22kVA. Simply adjust the parameters to test a variety of conditions with the easy-to-use WPT software.

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Chroma 17040E Charge/Discharge Test System

Some EV charging station operators aim to relieve drivers' range anxiety and achieve more flexible power dispatch by combining renewable energy sources such as solar energy and battery energy storage systems (BESS). The biggest challenge facing BESS manufacturers lies in designing the balancing between each battery cell in the energy storage cabinet, especially in the application of fast frequency regulation on the power grid, which directly affects the quality and safety of the system.

Chroma ATE leverages its extensive practical experience in energy storage testing to provide solutions that help customers to efficiently identify key issues in their battery systems. This requires verification of the status of each battery cell in the BESS. The Chroma 17040E charge/discharge test system delivers a high voltage of 1700V and a rated power of 200kW per unit, which can be paralleled for increased power. With a fast current rise time of 1ms, it can simulate the charge/discharge behavior of the BESS during power regulation through the PCS to the power grid. The 17040E system's software reads the battery cell information from the battery management system (BMS) and detects the voltage changes of each cell during the power regulation process. It then uses this information to identify voltage changes of the battery cells and find defects in the assembly quality of the BESS. This helps to avoid over-charging or over-discharging of the battery cells and identify design errors, making for a suitable solution for BESS design verification, incoming and outgoing inspection, production testing, and applying for product certification.
 

Chroma 61800 Regenerative Grid Simulator

The Chroma 61815 Grid Simulator has four-quadrant output capability. It can simulate various voltage and frequency outputs for grid-tied inverters as well as serve as a four-quadrant AC load for testing standalone inverters. Since its launch, the instrument has been adopted by various industry-leading companies in the energy storage industry, which has enabled us to accumulate substantial experience in the testing of hybrid inverters.

The Grid Simulator’s highly efficienct energy feedback capability enables it to significantly reduce power consumption when simulating the grid for testing purposes. It also has advanced programmable functions such as List, Pulse, and Step for simulating various kinds of power line disturbance (PLD). In addition, in its optional regenerative AC load mode, the device can feed energy back to the grid to help manufacturers meet their energy-saving and carbon-reduction test requirements. It can also simulate various types of rectified and non-rectified loads with specific load modes such as Rectified, Lead/Lag, and Half-Wave Rectified, supported by the Instant Stand-By safety function.
 

Chroma Electric Vehicle Test Solutions

The global EV industry is growing rapidly, presenting significant business opportunities that attract investments from car manufacturers, charging station operators, battery manufacturers, and many others. Chroma has been actively involved in the international market for electric vehicle and battery testing for many years. We offer comprehensive test solutions for every stage from R&D to mass production, covering the entire supply chain from the vehicle itself to the upstream and downstream components.

The Chroma 8000 Automated Test System meets the requirements of SAE J1772 and GB/T 18487.1 for full function testing of AC level 1 and level 2 electric vehicle supply equipment (EVSE) and is built to address the testing needs of EVs' and PHEV's from R&D to QA, production, and field service.

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