Voltage-Doubling Rectifier Control for DC-Link Capacitor Current

The patent employs feedback control by detecting the current flowing through the inductor and using this information to control the switching elements. The controller adjusts the switching timing and duration based on the detected current, ensuring that the capacitors are charged within a safe current range while still achieving voltage doubling. This feedback mechanism prevents excessive current during mode switching while maintaining the productivity benefits of voltage-doubling rectification.

The patent applies preliminary action by carefully controlling the switching elements to charge the DC-link capacitors in a predetermined sequence and within a specified time window during mode switching. The controller pre-establishes the charging path and limits the charging current before excessive current can occur. This preliminary control of the charging process prevents capacitor damage while enabling the transition to voltage-doubling mode.

The patent uses feedback control to detect both the inductor current and the regenerative power conditions. When regenerative power is detected during mode switching, the controller adjusts the switching element control to manage the capacitor charging current. The feedback mechanism ensures that regenerative energy is utilized efficiently while preventing excessive current from damaging the capacitors, thus maintaining reliability during energy recovery operations.

The patent converts the potentially harmful regenerative current that could cause excessive capacitor current into a beneficial charging current for the DC-link capacitors. By controlling the switching elements to guide the regenerative current through the capacitors in a controlled manner, the system recovers energy that would otherwise be wasted while simultaneously charging the capacitors safely. This transforms the harmful effect into a useful function.