Patent ID: 7173834
Filing Date: 2007-02-06
Classification: H02M

Abstract:
1. A half-controlled silicon-controlled rectifying system, comprising: a first detection unit, which has a first input port receiving a triphase AC, for detecting a zero cross phase point of the triphase AC inputted into the first input port; a silicon-controlled rectifying unit, which has a second input port receiving the triphase AC, for rectifying the triphase AC into a DC current and for outputting a current; a DC bus, which is connected to the silicon-controlled rectifying unit and includes a charging capacitor, for receiving the current from the silicon-controlled rectifying unit and for converting the current into an electric energy and storing the electric energy in the charging capacitor; a second detection unit, which is connected to the DC bus, for detecting the voltage stored in the charging capacitor of the DC bus; and a control unit for receiving outputs of the first detection unit and the second detection unit, thereby determining whether to send a trigger signal to the silicon-controlled rectifying unit depending on the outputs of the first detection unit and the second detection unit to enable the triphase AC to flow through the second input port, Wherein when the triphase AC flows through the first input port, the first detection unit detects the zero cross phase of the voltage of the triphase AC and sends the trigger signal indicating the zero cross phase of the voltage into the control unit, and the control unit sends the trigger signal to conduct one of the silicon rectifiers in the silicon-controlled rectifying unit, the control unit determines whether the detected voltage value concerning the charging capacitor of the DC bus from the second detection unit is greater than a threshold conducting voltage, if the detected voltage value is greater than the threshold conducting voltage, the control unit sends a trigger signal to conduct all the silicon-controlled rectifiers of the silicon-controlled rectifying unit, if not, the control unit sends out the trigger signal to conduct a silicon rectifier of the silicon-controlled rectifying unit in the next time when the input triphase AC is close to the zero cross phase.