An example converter for a switched reluctance (SR) generator includes one or more gate driver circuits that are not only used to synchronously control switches, such as insulated gate bipolar transistors (IGBTs) of the converter, but also used to provide priming function during start-up of the generator. Since, an SR generator does not have to ability to self provide magnetic flux, priming current is provided to coils of the SR generator to initiate a magnetic flux. By using the gate drive circuit to provide the priming current, an additional priming circuit is not required. As a result, the converter design is more streamlined, with reduced complexity, cost, and size. When a bus voltage of the converter is below a threshold level, the one or more gate drive circuits can provide the priming current on the bus to initiate the SR generator.

An apparatus for delay angle compensation for flying start function in a medium-voltage inverter is disclosed. The apparatus generates generate a phase angle () by converting a three-phase voltage of an inverter output terminal to dq-axis voltages (Vd, Vq), and calculate a compensation phase angle by a predetermined delay time. In addition, the apparatus generates an initial angle for the flying start by aggregating the compensation phase angle with the phase angle (). The apparatus may drive a high-voltage motor more stably, because an error between a command voltage phase angle and an actual output voltage phase angle may be reduced, when electric power of the medium voltage inverter is restored after a trip or an instantaneous blackout occurs.

An apparatus for delay angle compensation for flying start function in a medium-voltage inverter is disclosed. The apparatus generates generate a phase angle () by converting a three-phase voltage of an inverter output terminal to dq-axis voltages (Vd, Vq), and calculate a compensation phase angle by a predetermined delay time. In addition, the apparatus generates an initial angle for the flying start by aggregating the compensation phase angle with the phase angle (). The apparatus may drive a high-voltage motor more stably, because an error between a command voltage phase angle and an actual output voltage phase angle may be reduced, when electric power of the medium voltage inverter is restored after a trip or an instantaneous blackout occurs.

An inverter device includes an inverter circuit, which has switching elements in a bridge connection, a capacitor, which is connected in parallel to the input side of the inverter circuit, a control device, which controls the inverter circuit, a temperature detector, which detects the temperature of the capacitor, a degree-of-deterioration determiner, which determines the degree of deterioration of the capacitor, and a warm-up controller. When the temperature of the capacitor detected by the temperature detector is lower than a prescribed temperature, the warm-up controller controls the switching elements of the inverter circuit to supply a direct current set based on the degree of deterioration and the temperature of the capacitor to the coil of an electric motor connected to the output side of the inverter circuit.

An inverter device includes an inverter circuit, which has switching elements in a bridge connection, a capacitor, which is connected in parallel to the input side of the inverter circuit, a control device, which controls the inverter circuit, a temperature detector, which detects the temperature of the capacitor, a degree-of-deterioration determiner, which determines the degree of deterioration of the capacitor, and a warm-up controller. When the temperature of the capacitor detected by the temperature detector is lower than a prescribed temperature, the warm-up controller controls the switching elements of the inverter circuit to supply a direct current set based on the degree of deterioration and the temperature of the capacitor to the coil of an electric motor connected to the output side of the inverter circuit.

A power inverter device includes an inverter that converts a direct-current (DC) power to an alternating-current (AC) power having an output AC voltage, and a capacitor circuit electrically connected to the inverter. The capacitor circuit is operable to start supplying a capacitor voltage to the inverter at a time point when a predetermined waiting time lapses from a zero cross point of the output AC voltage at a starting up of the inverter circuit, wherein the capacitor voltage has a phase shifted by /4 radian from the output AC voltage. The inverter is operable to generate the output AC power based on the capacitor voltage and the DC power. The predetermined waiting time is a duration is equal to 2n+3/4 radian or 2n+7/4 radian of a phase of the output AC voltage (n is an integer not smaller than zero). This power inverter device can reduce a ripple power of the input power early after the starting-up.

A power inverter device includes an inverter that converts a direct-current (DC) power to an alternating-current (AC) power having an output AC voltage, and a capacitor circuit electrically connected to the inverter. The capacitor circuit is operable to start supplying a capacitor voltage to the inverter at a time point when a predetermined waiting time lapses from a zero cross point of the output AC voltage at a starting up of the inverter circuit, wherein the capacitor voltage has a phase shifted by /4 radian from the output AC voltage. The inverter is operable to generate the output AC power based on the capacitor voltage and the DC power. The predetermined waiting time is a duration is equal to 2n+3/4 radian or 2n+7/4 radian of a phase of the output AC voltage (n is an integer not smaller than zero). This power inverter device can reduce a ripple power of the input power early after the starting-up.

Electrical power system and methods for operating the power systems are disclosed. Embodiments include power systems configured for connection to loads that include green energy systems, such as hydrogen electrolyzers. Embodiments include multiple subcomponents, for example inverters, that alone produce insufficient power for the load but together produce sufficient power for the load. Embodiments include power systems with subcomponent input ports connected in parallel and output ports connected in parallel. Embodiments minimize the flow of electrical power between subcomponents during startup, and still further embodiments delay connection to the load until sufficient power is available to power the load. Additional embodiments allow two or more connected subcomponents to share a load larger than either of the subcomponents is capable of handling alone.

Electrical power system and methods for operating the power systems are disclosed. Embodiments include power systems configured for connection to loads that include green energy systems, such as hydrogen electrolyzers. Embodiments include multiple subcomponents, for example inverters, that alone produce insufficient power for the load but together produce sufficient power for the load. Embodiments include power systems with subcomponent input ports connected in parallel and output ports connected in parallel. Embodiments minimize the flow of electrical power between subcomponents during startup, and still further embodiments delay connection to the load until sufficient power is available to power the load. Additional embodiments allow two or more connected subcomponents to share a load larger than either of the subcomponents is capable of handling alone.