Recent Developments in Fault Detection and Power Loss Estimation of Electrolytic Capacitors

Abstract

International audienceThis paper proposes a comparative study of current-controlled hysteresis and pulsewidth modulation (PWM) techniques, and their influence upon power loss dissipation in a power-factor controller (PFC) output filtering capacitors. First, theoretical calculation of low-frequency and high-frequency components of the capacitor current is presented in the two cases, as well as the total harmonic distortion of the source current. Second, we prove that the methods already used to determine the capacitor power losses are not accurate because of the capacitor model chosen. In fact, a new electric equivalent scheme of electrolytic capacitors is determined using genetic algorithms. This model, characterized by frequency-independent parameters, redraws with accuracy the capacitor behavior for large frequency and temperature ranges. Thereby, the new capacitor model is integrated into the converter, and then, software simulation is carried out to determine the power losses for both control techniques. Due to this model, the equivalent series resistance (ESR) increase at high frequencies due to the skin effect is taken into account. Finally, for hysteresis and PWM controls, we suggest a method to determine the value of the series resistance and the remaining time to failure, based on the measurement of the output ripple voltage at steady-state and transient-state converter working

Single-Phase Input Variable-Speed AC Motor System Based on an Electrolytic Capacitor-Less Single-Stage Boost Three-Phase Inverter

“…Then the modulation index can be derived as follows, according to (16) and the relationship between amplitude of output phase voltage and dc-link voltage:…”

“…But for these single-phase to three-phase converter driven home electrical appliances with diode rectifiers, large-capacity aluminum electrolytic capacitors (E-caps) are often used in dc-link to balance the instantaneous input-output power difference due to their large capacitance and low cost. However, they induce some undesirable properties to the system: (1) low input power factor and requiring an additional power factor correction circuit and a pre-charging circuit [7]- [10], or a large inductance reactor [11]- [14] at least, which is bulky, expensive and also produces power loss, and (2) low reliability for its finite lifetime and high failure rate due to wear-out degradation failure [15] [16]. In some adjustable-speed AC motor systems for home electrical appliances, such as air conditioner compressors, neither the rapid load variation nor the regenerative braking is needed.…”

Rectifier Capacitor Filter Stress Analysis When Subject to Regular Voltage Fluctuations

“…(27) By substituting (20) and (21) into (27), and comparing the result with the capacitor RMS current equation under ideal power supply conditions (14), the following relationship can be derived:…”

Failure model and detecting method for MOSFET degradation in DC-DC power converters

“…), some researchers have analyzed the impact of the main parameters of aluminum electrolytic capacitors (such as capacitance, loss angle, leakage current, ripple current, etc.) on its life (Braham et al, 2010;Abdennadher and Venet, 2010;Buiatti et al, 2010;Sun et al, 2010). In the case of MOSFETs, several methods have been proposed to detect faults in MOSFET, for example, short-circuit and open-circuit faults.…”