Photovoltaic grid-connected inverter test solution

吹田电气SUITA

Photovoltaic grid-connected inverter test solution [Copy link]

With the implementation of the "dual carbon" policy, the new energy industry is rising rapidly and attracting much attention. While the country strongly supports the photovoltaic industry, the inverter industry has also ushered in new opportunities and challenges. Faced with the dual crisis of increasingly tense energy situation and increasing electricity demand, the public power grid has put forward higher requirements for the quality and performance of grid-connected inverters. However, there are some inverters in the market that do not meet the standards, and even difficult to pass the conventional electrical characteristics test, such as over/under voltage protection, anti-islanding effect, high/low voltage ride-through, harmonic distortion, maximum power point tracking (MPPT), etc. In order to meet this challenge, it is necessary to develop a series of strict and comprehensive test schemes for grid-connected inverters to ensure that their quality and performance meet the relevant standards and can operate safely, stably and for a long time. This will not only help meet energy needs, but also promote greater development of the inverter industry.

What is a photovoltaic power generation system

Photovoltaic grid-connected power generation system is a new energy power generation system. Its working principle is to first use the photovoltaic effect of photovoltaic semiconductor materials to convert solar energy into direct current, then convert direct current into alternating current through AC/DC conversion, and finally transmit the generated alternating current to the user end through the power grid. General photovoltaic power generation systems are divided into centralized systems and distributed systems. Centralized systems mainly refer to large-scale photovoltaic power stations built in desert areas, which can collect solar energy in large quantities and stably, and then provide energy for grid loads through high-voltage long-distance power supply; distributed systems mainly refer to photovoltaic power generation projects built on the roofs of urban buildings, which solve the electricity consumption problems of users nearby and realize the compensation and transmission of power supply differences through grid connection. Although the methods of power transmission are different, both are a kind of grid-connected photovoltaic power generation system.

What is an Inverter

An inverter is an electrical device that can change the voltage, frequency, number of phases and other electrical quantities or characteristics of a power system. Its main function is to convert DC power into AC power. It consists of an inverter bridge, control logic and filter circuits, and the core part is a PWM integrated controller. The application field of the inverter is very wide, such as new energy vehicles, photovoltaic power generation systems, wind power generation systems, televisions, computers and other electrical equipment. The inverters used in the field of photovoltaic power generation can be roughly divided into two types: grid-connected inverters and off-grid inverters. The input end of the grid-connected inverter is connected to the parallel photovoltaic module, and the input DC power is converted into AC power through an IGBT power module or a field effect transistor, and the DSP conversion controller is used to improve the quality of the output AC power to make it close to a sine wave current. The biggest feature of the grid-connected inverter is that the power system has high power and low cost, and the electric energy can be accurately controlled without storing the electric energy. The DC power generated by the photovoltaic is directly transmitted to the public power grid after conversion, ensuring that the AC power is fully synchronized with the public power grid to meet the frequency and phase characteristics required for the AC power.

solution

Suita Electric (SUITA) has been committed to the research of the photovoltaic industry and provides professional testing solutions for photovoltaic inverters. At present, SUITA has launched a new generation of test instruments for inverter grid-connected tests in the field of photovoltaic power generation, including SPSD series bidirectional programmable DC power supply, SPSA4015R regenerative AC grid simulation power supply, SPAW7000 power analysis recorder and other products, which have ultra-high power accuracy and are designed to meet user needs. In SUITA's test solution, the SPSD series bidirectional programmable DC power supply is connected to the input end of the photovoltaic inverter to simulate the input power of solar cells. At the same time, the SPSA4015R regenerative AC grid simulation power supply is connected to the output end of the photovoltaic inverter to simulate the grid load. The harmonics, output power, conversion efficiency and other performance indicators of the photovoltaic inverter are measured by the SPAW7000 power analysis recorder. In order to further improve the convenience and visual analysis of the test process, SUITA also provides powerful host computer software to provide engineers with comprehensive data analysis support. This series of efficient and advanced products and solutions marks SUITA's leading position in the industry and provides strong support for the development of the photovoltaic industry.

Key Benefits

1. Ultra-high precision : The SPAW7000 high-precision power analyzer has a measurement accuracy of up to 0.01% and a high bandwidth of 0.1 Hz-5 MHz, and can accurately measure key parameters such as input and output voltage, current, and power.

2. High-speed calculation: SPAW7000 power analysis recorder has current phase compensation function, integration function, fast Fourier transform function, etc., and the data update rate can be as fast as 10ms, which can perform high-speed calculation while ensuring high precision.

3. Support harmonic analysis: SPAW7000 power analysis recorder can measure up to 500 harmonics and analyze the harmonics of 7 power channels at the same time, which complies with IEC61000-4-7 standard. In addition, it can also measure and analyze voltage fluctuations and flickers according to relevant IEC standards.

4. Large-capacity data storage and analysis: It can store voltage, current, power and other measurement data as well as voltage and current display waveform data in real time, with the fastest storage rate reaching 100 times/second, and has built-in 512GB large-capacity storage space (optional 1TB), so that its comprehensive performance can be evaluated, so as to better optimize and adjust the system.

5. Humanized operation interface: It has a user-friendly interface and operation mode, and a graphical functional module design so that testers can easily set up and control the test. The high-definition large display can also display a variety of information such as numerical values, waveforms, bar graphs and trends in the same interface.

6. High performance: The power of the power supply can reach up to 15KW, the voltage can reach up to 1500V, and the measurement range can be further expanded by connecting multiple power supplies in series and parallel, fully meeting the testing requirements of grid-connected inverters.

7. Safe and reliable: In addition to the power supply function, the power supply also has the function of electronic load and provides a variety of protection functions, such as OVP, OCP, OPP, OTP, power-off and input undervoltage protection, making the test process safer and more reliable.

8. Multifunctional developer mode: built-in function generator, complete programming functions and minimum controllable programming time as low as 10ms, supports arbitrary waveform generation, such as standard solar cell IV curve waveform simulation.