A power electronics system, comprising a first inverter configured to receive DC power from a power source and a second inverter configured to receive DC power from the power source is provided. The system includes a first output inductor connected in series to an output of the first inverter, a second output inductor connected in series to an output of the second inverter, a coupling inductor configured to receive current from the first output inductor and the second output inductor, and an AC power output.

An example power system for supplying AC output power to an AC load includes: a variable-speed generator configured to be driven by a prime mover, the generator comprising a first winding and a reference tap in the first winding; a rectifier configured to rectify an input voltage from the first winding to output a positive DC signal with respect to the reference tap and a negative DC signal with respect to the reference tap; a first boost converter configured to convert the positive DC signal to generate a positive DC bus voltage with respect to the reference tap; a second boost converter configured to convert the negative DC signal to generate a negative DC bus voltage with respect to the reference tap; and an inverter circuit configured to convert the positive DC bus voltage and the negative DC bus voltage to an AC output signal with respect to the reference tap.

A voltage supply system and a power source that, in a voltage supply system in which a plurality of power sources (e.g., DC-DC converters) are connected in parallel, enable each power source to be set at a desired load ratio. The power source is used in a voltage supply system including a power source configured to output a voltage in a constant voltage mode on the basis of a first target voltage, and is connected in parallel to the constant voltage power source, the power source including a voltage generation unit configured to output a voltage switchably between a constant voltage mode based on a second target voltage greater than the first target voltage and a constant current mode based on a current limit value.

A power apparatus applied in a solid state transformer structure includes an AC-to-DC conversion unit, a first DC bus, and a plurality of bi-directional DC conversion units. First sides of the bi-directional DC conversion units are coupled to the first DC bus. Second sides of the bi-directional DC conversion units are configured to form at least one second DC bus, and the number of the at least one second DC bus is a bus number. The bi-directional DC conversion units receive a bus voltage of the first DC bus and convert the bus voltage into at least one DC voltage, or the bi-directional DC conversion units receive at least one external DC voltage and convert the at least one external DC voltage into the bus voltage.

In an embodiment, a power module may include: a plurality of first stages, each having an H-bridge to receive an incoming AC voltage at a first frequency and rectify the incoming AC voltage to a DC voltage; a plurality of DC buses, each to receive the DC voltage from one of the plurality of first stages; a plurality of second stages, each coupled to one of the plurality of DC buses to receive the DC voltage and output a second AC voltage at a second frequency; and a hardware configuration system having fixed components and optional components to provide different configurations for the power module.

The disclosure discloses a method and device for detecting insulation state in a conversion system, wherein the conversion system includes an excitation source, a converter having an input end coupled to the excitation source, a connection element coupled between an output end of the converter and a reference point, and a coupling impedance having a first end coupled to the excitation source and a second end coupled to the reference point, the method for detecting insulation state including steps of: S1, controlling at least one main power switch of the converter not to switch; S2, detecting a pulse current signal of the connection element; and S3, processing the pulse current signal and outputting a partial discharge information, the partial discharge information indicating an insulation state of an isolating transformer in the converter. The disclosure can overcome electromagnetic interference of high frequency steep waves on a partial discharge signal.

Embodiments of the present disclosure provide an insulation monitoring device applied to a power system and a power system. The power system includes at least one power electronic converter module. The insulation monitoring device includes an insulation component, a signal source, an impedance module, and a monitoring module. The insulation component at least partially wraps around the power electronic converter module. The signal source is electrically coupled to a circuit node in the power electronic converter module, the impedance module is connected between the signal source and the insulation component, and the monitoring module is configured to monitor an insulation resistance value of the insulation component, so that an insulation state of the power electronic converter module may be determined.

In one embodiment, an EV charging system includes: a plurality of first converters to receive and convert grid power at a distribution grid voltage to at least one second voltage; a high frequency transformer coupled to the first converters to receive the at least one second voltage and output at least one high frequency AC voltage; and a plurality of port rectifiers coupled to a plurality of secondary windings of the high frequency transformer, each of the port rectifiers comprising a unidirectional AC-DC converter to receive and convert the at least one high frequency AC voltage to a DC voltage. At least some of the port rectifiers may be coupled in series to provide at least one of a charging current or a charging voltage to at least one dispenser to which at least one EV is to couple.

A power conversion system comprises a plurality of power modules, each including a power input end; a charging input end; a power output end; at least one power conversion unit, each including an AC/DC conversion unit and at least one DC-Bus capacitor and being connected to the power input end and the power output end; and a pre-charging unit connected to the charging input end for receiving direct current and connected to the DC-Bus capacitor. The pre-charging unit starts to charge the DC-Bus capacitor of one of the power modules when said power module breaks down or the load of the power conversion system is light so that no current flows through the AC/DC conversion unit. The power input ends of the power modules are connected in series and then connected to an AC power source, and the power output ends of the power modules are connected in parallel.

An embodiment solar cell system includes a first photovoltaic (PV) module and a second PV module connected in series with each other, a differential power processing (DPP) converter configured to convert electricity generated by the first PV module and the second PV module, using a magnetic material having a multi-winding structure, and to provide the converted electricity to a battery, and a control signal generator configured to generate a control signal that controls a main switch for controlling an input-side current path and an output-side current path of the DPP converter, and to adjust a pulse width of the control signal such that a magnetizing current of the DPP converter becomes substantially zero.