SYSTEM FOR CONTROLLING SWITCH OF SINGLE-PHASE DOUBLE CONVERSION UPS

摘要

A switching control system of a single phase double conversion UPS(Uninterruptible Power Supply) is provided to prevent EMI(Electro Magnetic Interference) generation by reducing a switching loss and the number of switching of an inverter. A buck-boost converter(304) converts a DC voltage outputted from a PFC(Power Factor Corrector)(303) into a variable DC voltage. An inverter(305) converts the variable DC voltage outputted from the buck-boost converter into an AC voltage. A memory(311) stores information about a triangle wave signal and a reference wave signal of a fixed frequency. The buck-boost converter provides a DC voltage of a fixed level in a PAWM(Pulse Amplitude Width Modulation) section according to a control of a control part(309). The buck-boost converter provides the variable DC voltage in a PAM(Pulse Amplitude Modulation) section according to the control of the control part. The inverter performs a SPWM(Sinusoidal Pulse Width Modulation) in the PAWM section according to the control of the control part. The inverter performs an over modulation in the PAM section according to the control of the control part.