The pulse width modulation control method and RF band power supply device according to the present invention are a pulse width modulation (PWM) control of a single phase PWM inverter in which the modulated wave frequency fs of a modulated wave is set in the RF band. The present control includes each of (a) a frequency synchronization control in which the carrier wave frequency fc of the carrier wave is set to even N times the modulated wave frequency fs, (b) an odd function control in which the modulated wave is set to a sine wave of an odd function and the carrier wave is set to a triangle wave of an odd function, and (c) a phase synchronization control in which the carrier wave is synchronized in phase with the modulated wave in each cycle of the modulated wave.

The pulse width modulation control method and RF band power supply device according to the present invention are a pulse width modulation (PWM) control of a single phase PWM inverter in which the modulated wave frequency fs of a modulated wave is set in the RF band. The present control includes each of (a) a frequency synchronization control in which the carrier wave frequency fc of the carrier wave is set to even N times the modulated wave frequency fs, (b) an odd function control in which the modulated wave is set to a sine wave of an odd function and the carrier wave is set to a triangle wave of an odd function, and (c) a phase synchronization control in which the carrier wave is synchronized in phase with the modulated wave in each cycle of the modulated wave.

Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers. When the primary side leads the secondary side, the ultracapacitor/battery discharges and causes the UPS to supply power to the data center, and when the secondary side leads the primary side, power flows from the grid back to the UPS, thereby recharging the ultracapacitor/battery.

Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers. When the primary side leads the secondary side, the ultracapacitor/battery discharges and causes the UPS to supply power to the data center, and when the secondary side leads the primary side, power flows from the grid back to the UPS, thereby recharging the ultracapacitor/battery.

The present invention discloses a single-phase non-isolated inverter, comprising: a first DC-side capacitor, a second DC-side capacitor, a first switch unit, a second switch unit, a third switch unit, a fourth switch unit, a fifth switch unit, a sixth switch unit, a seventh switch unit, and an eighth switch unit. When the single-phase non-isolated inverter is operated at a zero-voltage switching state, the seventh switch unit and the eighth switch unit are switched to short circuit for forming a short-circuit path between the bus lines. Briefly speaking, this novel single-phase non-isolated inverter has reactive power capability. In addition, according to an adjusting signal of a PI controller, micro controller of the single-phase non-isolated inverter is able to properly adjusts the duty cycle of a switch unit driving signal of the fifth switch unit and the sixth switch unit, so as to cancel the capacitor voltage unbalance between two DC-side capacitors.

Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers. When the primary side leads the secondary side, the ultracapacitor/battery discharges and causes the UPS to supply power to the data center, and when the secondary side leads the primary side, power flows from the grid back to the UPS, thereby recharging the ultracapacitor/battery.

Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers. When the primary side leads the secondary side, the ultracapacitor/battery discharges and causes the UPS to supply power to the data center, and when the secondary side leads the primary side, power flows from the grid back to the UPS, thereby recharging the ultracapacitor/battery.

A control method of a three-phase multi-level inverter includes: determining a modulation ratio based on output of the three-phase multi-level inverter, where the modulation ratio indicates a ratio of an amplitude value of a sinusoidal modulation wave in pulse width modulation to an amplitude value of a carrier; generating, based on the modulation ratio and a modulation ratio threshold, a common-mode voltage regulation signal for regulating a common-mode voltage in phase voltages of the three-phase multi-level inverter; adding the common-mode voltage regulation signal and a differential-mode voltage regulation signal for regulating a differential-mode voltage in the phase voltages of the three-phase multi-level inverter to obtain a composite regulation signal, where the composite regulation signal is presented as a modulation wave for discontinuous pulse width modulation (DPWM); and generating, based on the composite regulation signal, drive signals for controlling switches of phases of the three-phase multi-level inverter.

The present invention provides an isolated power supply circuit with a programmable function and a control method thereof. The isolated power supply circuit includes: a transformer circuit, a power switch circuit, a control circuit, and a discharge circuit. The control circuit generates an operation signal and a bleeding signal according to a setting signal. The discharge circuit is coupled to an output node, for generating a discharging current. When the programmable output voltage at the output node switches between different predetermined levels, in a transition period, the bleeding signal adjusts the discharging current to discharge the output node, such that the transition period is shortened.

A control part determines that a contactor is in an open state, based on a voltage at both ends of a smoothing capacitor and a current flowing through a direct-current power supply. In a state in which rotational speed is greater than or equal to a speed threshold value, the control part controls both inverters by shutdown control and brings both contactors into an open state. After the rotational speed reaches less than the speed threshold value, the control part controls a failure-side inverter by active short-circuit control, and drives a normal-side inverter using discharge torque of a smoothing capacitor. After eliminating an abnormal voltage state, the control part controls a normal contactor to a closed state and drives a rotating electrical machine by one of the inverters.