In new energy vehicles, motor, battery and motor control technology are the three cores of new energy vehicles. The core of motor control technology requires high-efficiency motor-controlled inverter technology, which requires a powerful IGBT module and a matching DC-Link capacitor. The importance of the IGBT module is self-evident, and the performance of the DC-Link capacitor cannot be ignored, so the reliable detection of the capacitor is an indispensable and important link.

Solution Details,

In practical applications, the high-frequency characteristics of large capacitors are far more complicated than the ideal state. Therefore, conventional automatic component analyzers or impedance analyzers do not have a dedicated four-terminal test fixture and the internal resistance of the instrument is too large. The partial pressure of the load test terminal is too small, resulting in unstable or even inaccurate test results.
After the instrument is warmed up for half an hour, use the test fixture to short-circuit to zero, and then select Cs-RS (ESR) as the test parameter, measure the capacitance under test with the test fixture, and test the capacitance under test with 100Hz, 1kHz, 10kHz, 40kHz, and 100kHz respectively. , record the measurement results, and then select the two frequencies with the closest Rs(ESR) as the test frequencies. In SETUP, set one of the two frequencies selected above as the fundamental frequency, then set the test frequency in the main test interface to the other frequency, and change the function to Cs-Rs-Ls to get accurate test values.

Instruments List,
1 set of TH2638