Electric power conversion device, motor driving device, and refrigeration cycle application apparatus

An electric power conversion device for supplying an output voltage to a load from output terminals, comprising:

• a rectifier circuit to rectify an AC voltage and to output a rectified voltage;
• a booster circuit to supply the output voltage to the output terminals;
• a voltage detector to detect the output voltage and to output a voltage detection value indicating the output voltage;
• and
• a controller, wherein
• the booster circuit has
• a reactor connected to the rectifier circuit,
• a smoothing capacitor to smooth the rectified voltage, thereby generating the output voltage, and
• a switching element to short-circuit the reactor during a conduction period which is a period of an ON state of the switching element, and
• the controller controls the conduction period of the switching element based on the voltage detection value so that a first pulsation frequency which is a frequency of pulsation of the output voltage is higher than a second pulsation frequency which is a frequency of pulsation of the rectified voltage, wherein the controller
• controls the conduction period for times when the voltage detection value is less than or equal to a predetermined threshold value so as to bring an average value of the voltage detection value close to a predetermined target voltage, and
• controls the conduction period for times when the voltage detection value is over the threshold value so that the conduction period becomes shorter than the conduction period for times when the voltage detection value is less than or equal to the threshold value.