A power conversion device configured to convert electric power from a power source to a load, comprising: a voltage changing device including a rectification unit configured to prevent backflow of a current from a side of the load to a side of the power source, the voltage changing device being configured to change a voltage of power from the power source to a predetermined voltage; a commutation device configured to perform commutation operation in which a current flowing through the voltage changing device is caused to flow into an other path; wherein a path along which the commutation device is provided is the other path; wherein the commutation device includes a transformer, a commutation rectification unit, and elements of a transformer drive circuit configured to drive the transformer, and wherein the commutation rectification unit of the commutation device is connected in parallel to the rectification unit of the voltage changing device, wherein a secondary-side winding of the transformer is connected in series to the commutation rectification unit; and a controller configured to control the voltage changing device and the commutation device, characterized by a signal generating module device configured as a module to receive an input signal (sw), and generate and send an output signal (sa), wherein the input signal (sw) is an operation signal (sw) from the controller for putting the voltage changing device into or out of operation, and the output signal (sa) is a drive signal (sa) for running the voltage changing device, wherein the signal generating module device is configured to feed the drive signal (sa) for running the voltage changing device back to the controller; wherein based on the drive signal (sa), the controller is configured to generate a commutation signal (sb) that is matched to the drive signal (sa) in terms of timing, and send the commutation signal (sb) for running the commutation device, wherein the input signal has an on-pulse width greater than a length of time where the output signal generated by the signal generating module device is turned on. a voltage changing device including a rectification unit configured to prevent backflow of a current from a side of the load to a side of the power source, the voltage changing device being configured to change a voltage of power from the power source to a predetermined voltage; a commutation device configured to perform commutation operation in which a current flowing through the voltage changing device is caused to flow into an other path; wherein a path along which the commutation device is provided is the other path; wherein the commutation device includes a transformer, a commutation rectification unit, and elements of a transformer drive circuit configured to drive the transformer, and wherein the commutation rectification unit of the commutation device is connected in parallel to the rectification unit of the voltage changing device, wherein a secondary-side winding of the transformer is connected in series to the commutation rectification unit; and a controller configured to control the voltage changing device and the commutation device, characterized by a signal generating module device configured as a module to receive an input signal (sw), and generate and send an output signal (sa), wherein the input signal (sw) is an operation signal (sw) from the controller for putting the voltage changing device into or out of operation, and the output signal (sa) is a drive signal (sa) for running the voltage changing device, wherein the signal generating module device is configured to feed the drive signal (sa) for running the voltage changing device back to the controller; wherein based on the drive signal (sa), the controller is configured to generate a commutation signal (sb) that is matched to the drive signal (sa) in terms of timing, and send the commutation signal (sb) for running the commutation device, wherein the input signal has an on-pulse width greater than a length of time where the output signal generated by the signal generating module device is turned on.