Abstract: A DC capacitor degradation alarm circuit is a capacitor degradation detection device including two filter circuits and a degradation detection element. The two filter circuits, which receive a rectified voltage and perform filtering operation, are coupled in parallel and include a plurality of capacitor modules coupled in series. Each capacitor module can be a single capacitor or includes a plurality of capacitors coupled in series or parallel to allow users to arrange construction thereof to receive required capacitance. The degradation detection element electrically bridges the two filter circuits with connection nodes located between the capacitor modules to instantly detect a voltage difference value of the two filter circuits online and perform operation by incorporating with total output voltage to get voltage difference value percentage.

Abstract: A DC power supply insulation fault detection circuit includes a plurality of circuit breaking elements located at a positive terminal and a negative terminal of each circuit in a power supply system, at least one leakage current detector located in the circuit, and at least one positive voltage transient compensator and at least one negative voltage transient compensator respectively bridging the positive terminal and negative terminal of the power supply system. The positive and negative voltage transient compensators respectively include a charge/discharge circuit to allow an energy storage circuit to be charged. When grounding insulation deterioration takes place at the positive or negative terminal of the leakage current detector, a leakage current loop is formed so that energy storage elements discharge and the leakage current detector detects current variations on the positive and negative terminals, and issue an alarm signal or control cutoff of the circuit breaking elements.

Abstract: A DC power supply insulation fault detection circuit includes a plurality of circuit breaking elements located at a positive terminal and a negative terminal of each circuit in a power supply system, at least one leakage current detector located in the circuit, and at least one positive voltage transient compensator and at least one negative voltage transient compensator respectively bridging the positive terminal and negative terminal of the power supply system. The positive and negative voltage transient compensators respectively include a charge/discharge circuit to allow an energy storage circuit to be charged. When grounding insulation deterioration takes place at the positive or negative terminal of the leakage current detector, a leakage current loop is formed so that energy storage elements discharge and the leakage current detector detects current variations on the positive and negative terminals, and issue an alarm signal or control cutoff of the circuit breaking elements.

Abstract: A phase-controlled AC voltage stabilizing circuit includes a buffer device connected between an input power side and an exciting side of a transformer to provide flywheel paths of exciting current within the positive half cycle and negative half cycle of input power. A pulse width modulation control device is connected between the buffer device at the exciting side of the transformer and a neutral point of a power supply system to switch ON and OFF a number of times within each half cycle of the input power to allow an inductor to regulate the variable voltage so that waveform of the exciting current of the transformer is smoother. By regulating the voltage at the output side of the transformer, response time of stabilizing voltage is faster and distortion of the waveform is smaller.

Abstract: An isolation-type AC fault current limited circuit is a current regulation circuit including a transformer and a conduction circuit. The transformer includes a primary winding coupled in series between a power supply input system and a load output system, and a secondary winding sharing a common iron core with the primary winding and electrically isolated therewith. The conduction circuit is connected to the secondary winding and includes a switch and a breaking element coupled in series. In the event that short circuit takes place on the power system, the breaking element induces great short circuit current of the primary winding and is fused to cut off conduction, so that the transformer becomes an open circuit to increase magnetizing reactance with high impedance to increase equivalent internal impedance of the power supply input system to limit fault current and allow circuit breaking devices of the power system to isolate short circuit.

Abstract: A DC capacitor degradation alarm circuit is a capacitor degradation detection device including two filter circuits and a degradation detection element. The two filter circuits, which receive a rectified voltage and perform filtering operation, are coupled in parallel and include a plurality of capacitor modules coupled in series. Each capacitor module can be a single capacitor or includes a plurality of capacitors coupled in series or parallel to allow users to arrange construction thereof to receive required capacitance. The degradation detection element electrically bridges the two filter circuits with connection nodes located between the capacitor modules to instantly detect a voltage difference value of the two filter circuits online and perform operation by incorporating with total output voltage to get voltage difference value percentage.

Abstract: The present invention discloses a circuit for detecting capacitance attenuation of a rectification/filter capacitor and a method thereof. A rectification circuit provides a capacitor with a rectified ripple voltage having a maximum lower than output voltage of a back-up power supply device. An isolation device isolates the rectified ripple voltage and let the back-up power supply device supply power to other power supply devices. The detection switch of an detection circuit is turned on to electrically connect the capacitor with a resistor, whereby the resistor conducts the rectified ripple voltage to charge and discharge the capacitor to obtain a peak-to-valley ratio and a discharging time. The capacitance is worked out from the peak-to-valley ratio, discharging time and resistance of the resistor. The deterioration extent of the capacitor is obtained from the variation of the capacitance. Therefore, the UPS system would not be shut off during detecting the capacitor.