A voltage inverter system driving a motor, the voltage inverter system comprising: a first switch configured to switch an output voltage from a voltage inverter to the motor; a second switch configured to switch a commercial power source to the motor; a controller configured to synchronize the output voltage of the voltage inverter with the commercial power source to provide a synchronized output command to the voltage inverter, wherein the controller comprises: a first PLL unit configured to determine input voltage information by receiving an input voltage of the voltage inverter; a comparator configured to compare an output command of the voltage inverter with an output of the first PLL unit to output a difference therebetween; a synchronous controller configured to synchronize the output command of the voltage inverter using the difference; and an inverter output unit configured to output the output voltage of the voltage inverter using a synchronized inverter output command received from the synchronous controller; wherein the voltage inverter system is characterized by: a reactor arranged between the first switch and the voltage inverter, wherein the controller further comprises a second PLL unit configured to determine output voltage information by receiving the output voltage from the output unit, wherein the synchronous controller synchronizes the output command of the voltage inverter by receiving the output voltage information from the second PLL unit. a first switch configured to switch an output voltage from a voltage inverter to the motor; a second switch configured to switch a commercial power source to the motor; a controller configured to synchronize the output voltage of the voltage inverter with the commercial power source to provide a synchronized output command to the voltage inverter, wherein the controller comprises: a first PLL unit configured to determine input voltage information by receiving an input voltage of the voltage inverter; a comparator configured to compare an output command of the voltage inverter with an output of the first PLL unit to output a difference therebetween; a synchronous controller configured to synchronize the output command of the voltage inverter using the difference; and an inverter output unit configured to output the output voltage of the voltage inverter using a synchronized inverter output command received from the synchronous controller; wherein the voltage inverter system is characterized by: a reactor arranged between the first switch and the voltage inverter, wherein the controller further comprises a second PLL unit configured to determine output voltage information by receiving the output voltage from the output unit, wherein the synchronous controller synchronizes the output command of the voltage inverter by receiving the output voltage information from the second PLL unit. a first PLL unit configured to determine input voltage information by receiving an input voltage of the voltage inverter; a comparator configured to compare an output command of the voltage inverter with an output of the first PLL unit to output a difference therebetween; a synchronous controller configured to synchronize the output command of the voltage inverter using the difference; and an inverter output unit configured to output the output voltage of the voltage inverter using a synchronized inverter output command received from the synchronous controller; wherein the voltage inverter system is characterized by: a reactor arranged between the first switch and the voltage inverter, wherein the controller further comprises a second PLL unit configured to determine output voltage information by receiving the output voltage from the output unit, wherein the synchronous controller synchronizes the output command of the voltage inverter by receiving the output voltage information from the second PLL unit. a reactor arranged between the first switch and the voltage inverter, wherein the controller further comprises a second PLL unit configured to determine output voltage information by receiving the output voltage from the output unit, wherein the synchronous controller synchronizes the output command of the voltage inverter by receiving the output voltage information from the second PLL unit.