Three-level power factor rectifier and method of operating the same

A three-level power factor rectifier, comprising:

• a diode bridge arm comprising a first diode and a second diode connected in series,
• a bridge arm assembly connected to the diode bridge arm in parallel, the bridge arm assembly comprising:
• a first bridge arm comprising a first switch, a second switch, a third switch, and a fourth switch connected in series and in sequence, and
• a second bridge arm connected to the second switch and the third switch in parallel, and the second bridge arm comprising a first freewheeling component and a second freewheeling component connected in series and in sequence,
• an input inductor coupled to a first node between the second switch and the third switch, coupled to a second node between the first diode and the second diode, and coupled to an input terminal that receiving an AC power source,
• a capacitor bank connected to the bridge arm assembly in parallel, and the capacitor bank comprising a first capacitor and a second capacitor connected in series and in sequence;
• a midpoint between the first capacitor and the second capacitor coupled to the first freewheeling component and the second freewheeling component, and
• a controller configured to operate the first bridge arm in a burst mode, and the burst mode comprising a burst period and a burst sleep period,
• wherein when the controller controls the first bridge arm operating in the burst sleep period, and the AC power source in a positive half cycle and a voltage value of the AC power source is greater than a first threshold, the controller turns on the first switch and the second switch;
• when the controller controls the first bridge arm operating in the burst sleep period, and the AC power source in a negative half cycle and the voltage value of the AC power source is less than a second threshold, the controller turns on the third switch and the fourth switch.

A method of operating a three-level power factor rectifier, the three-level power factor rectifier comprising a diode bridge arm, a bridge arm assembly, and a capacitor bank, and the bridge arm assembly comprising a first switch, a second switch, a third switch, and a fourth switch connected in series and in sequence to form a discharge path from an input inductor to the capacitor bank, the method comprising steps of:

• turning on and turning off the first switch, the second switch, the third switch, and the fourth switch to convert an AC power source into a DC power source,
• determining that entering a burst mode since the three-level power factor rectifier operates in a light-load condition, and the burst mode comprises a burst period and a burst sleep period,
• turning on the first switch and the second switch in the burst sleep period, while the AC power source in a positive half cycle and a voltage value of the AC power source is greater than a first threshold,
• turning on the third switch and the fourth switch in the burst sleep period, while the AC power source in a negative half cycle and the voltage value of the AC power source is less than a second threshold, and
• turning on the second switch and the third switch for a specific time period when entering the burst period from the burst sleep period.