Embodiments of this application provide an alternating current power supply circuit, a control method for an alternating current power supply circuit. The alternating current power supply circuit includes a rectifier module and an inverter module. The rectifier module includes a first inductor L1, a first branch, a second branch, a third branch, a first capacitor, and a second capacitor, the third branch includes a soft switching cell, the soft switching cell includes a first switching component and a second switching component that are reversely connected in series, and the first branch, the second branch, and the third branch form an I-type three-level topology or a T-type three-level topology. The inverter module includes a second inductor L1, a fourth branch, a fifth branch, a sixth branch, the first capacitor, and the second capacitor, the sixth branch includes the soft switching cell, and the fourth branch, the fifth branch.

In one embodiment, a method of operating a power electronic converter device for an electrical power converter system is provided. The power electronic converter device includes a converter circuit, a first converter, and a second converter. The first converter and the second converter are switch with a switching pattern such that the first converter and the second converter generate voltages with stepwise voltages changes and an output voltage of the power electronic converter device results frum a superposition of the voltages of the first converter and the second converter. The switching pattern includes switching instants for the second converter such that the voltage of the second converter leaves the fundamental voltage component of the voltage of the first converter unchanged, such that the second converter does not generate a fundamental component of the output voltage.

In one embodiment, a method of operating a power electronic converter device for an electrical power converter system is provided. The power electronic converter device includes a converter circuit, a first converter, and a second converter. The first converter and the second converter are switch with a switching pattern such that the first converter and the second converter generate voltages with stepwise voltages changes and an output voltage of the power electronic converter device results frum a superposition of the voltages of the first converter and the second converter. The switching pattern includes switching instants for the second converter such that the voltage of the second converter leaves the fundamental voltage component of the voltage of the first converter unchanged, such that the second converter does not generate a fundamental component of the output voltage.

A converter device has a converter that has power semiconductor switches and has a control device that is designed to drive the power semiconductor switches. The control device is designed to drive the power semiconductor switches so that electrical switching losses occurring in the converter are reduced during use.

Provided is a novel multi-level inverter with mixed device types and methods of controlling same. This novel multi-level inverter topology and control method allows the use of high frequency switching devices for controlled PWM switching, while also using lower frequency switching devices for directional switches. This combination of high frequency PWM switching devices with low frequency directional switching devices allows a cost reduction without a significant performance degradation.

A power switching circuit including a first DC/DC converter having a first input configured to receive a first input DC voltage, a second DC/DC converter having a first input configured to receive a second input DC voltage, a DC/AC inverter having a first input coupled to the output of the first DC/DC converter and a second input coupled to the output of the second DC/DC converter, the DC/AC inverter including n (n>2) switching legs, and at least one controller coupled to the first DC/DC converter, the second DC/DC converter, and the DC/AC inverter, the at least one controller configured to operate the DC/AC inverter to provide n AC signals to at least one load coupled to the DC/AC inverter by operating two of the n switching legs in a static state and n−2 of the n switching legs in a transition state.

A power switching circuit including a first DC/DC converter having a first input configured to receive a first input DC voltage, a second DC/DC converter having a first input configured to receive a second input DC voltage, a DC/AC inverter having a first input coupled to the output of the first DC/DC converter and a second input coupled to the output of the second DC/DC converter, the DC/AC inverter including n (n>2) switching legs, and at least one controller coupled to the first DC/DC converter, the second DC/DC converter, and the DC/AC inverter, the at least one controller configured to operate the DC/AC inverter to provide n AC signals to at least one load coupled to the DC/AC inverter by operating two of the n switching legs in a static state and n−2 of the n switching legs in a transition state.

Described herein is a method of operating a power electronic converter device for an electrical power conversion system. The power electronic converter device includes a converter circuit including an input side, an output side, a first converter, and at least one second converter. The second converter includes at least one floating cell with a DC intermediate circuit and semiconductor devices. The method includes: switching the semiconductor devices of the floating cell at switching instants determined with optimized pulse patterns or carrier-based pulse width modulation; determining a fundamental voltage component for the floating cell; and generating the fundamental voltage component in the actual voltage of the floating cell by modifying the switching instants, such that a voltage V.sub.C AF of the DC intermediate circuit is lying in a given reference voltage range for balancing the DC intermediate circuit of the floating cell.

Described herein is a method of operating a power electronic converter device for an electrical power conversion system. The power electronic converter device includes a converter circuit including an input side, an output side, a first converter, and at least one second converter. The second converter includes at least one floating cell with a DC intermediate circuit and semiconductor devices. The method includes: switching the semiconductor devices of the floating cell at switching instants determined with optimized pulse patterns or carrier-based pulse width modulation; determining a fundamental voltage component for the floating cell; and generating the fundamental voltage component in the actual voltage of the floating cell by modifying the switching instants, such that a voltage V.sub.C AF of the DC intermediate circuit is lying in a given reference voltage range for balancing the DC intermediate circuit of the floating cell.

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.