Capacitor Characteristics Measurement Setup by Using B–H Analyzer in Power Converters

In power electronics applications, the circuit performance and lifetime are closely related to the characteristics of the capacitors used. Moreover, in power converters, the capacitor is normally operated under high-current-amplitude nonsinusoidal-waveform conditions. However, the commonly used measuring instrument, the impedance analyzer, can only measure the frequency characteristics of a capacitor with small-current-amplitude sinusoidal-waveform conditions. To investigate the characteristics of a capacitor under practical operating conditions, two capacitor measurement systems are proposed by using a B-H analyzer in this paper. One of the measurement systems is designed for measuring the capacitance and equivalent series resistance of a capacitor under high-current-amplitude sinusoidal-waveform conditions. Via improving the signal injection method, a feedback measurement system is designed for measuring the loss of a capacitor under high-current-amplitude rectangular- or triangular-waveform conditions. In addition, both systems can measure the capacitor under wide-range frequency, dc bias voltage, and current amplitude conditions. Both measurement setups are analyzed and implemented. To demonstrate the feasibility of the systems, three different dielectric capacitors, such as aluminum electrolytic, ceramic, and film, are measured as examples.