FIELD: radio engineering, automation and computer engineering. SUBSTANCE: device has line of first alternating- current power supply circuit, line of second alternating-current power supply circuit, thyristor switches, which are connected to lines and which outputs are joined and connected to load. In addition charge decoupling units are connected to lines. Outputs of charge-decoupling units are connected to inputs of interface units through zero detectors and through units for voltage control and logical processing unit. Outputs of interface units are connected to control inputs of thyristor switches. Each voltage control unit has rectifier, parametric stabilizer, peak detector and comparator, which are connected in series. Second input of comparator is connected to input of reference voltage source. Logical processing unit has inverters, which inputs are connected to inputs of unit and to first inputs of NAND gates. Delay gates are connected to outputs of RS- flip-flop and to first inputs of AND gates, whic
