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.

An electronic transformer including a controller and a dimming control circuit. The controller is configured to control an output voltage. The dimming control circuit is configured to receive a user-input and output a control signal based on the user-input. The controller varies the output voltage based on the control signal. Wherein the output voltage is substantially the same regardless of an amplitude of an input voltage.

An electronic transformer including a controller and a dimming control circuit. The controller is configured to control an output voltage. The dimming control circuit is configured to receive a user-input and output a control signal based on the user-input. The controller varies the output voltage based on the control signal. Wherein the output voltage is substantially the same regardless of an amplitude of an input voltage.

A motor control system includes a VFD unit comprising a rectifier circuit having a plurality of phase legs each including thereon an upper switching unit and a lower switching unit, an inverter connected to the rectifier circuit by way of a DC link and having a plurality of switches therein controllable to provide a three-phase AC output power to a load, and a bypass relay unit comprising a bypass relay coupled to each of the phase legs of the rectifier circuit downstream from the lower switching unit. An isolation contactor unit is positioned between the inverter and the load and operable to selectively connect/disconnect the inverter to/from the load. The bypass relay unit is operable in a first and second positions to couple the rectifier circuit to the inverter and to couple the rectifier circuit to a bypass path that bypasses the inverter.

A method of controlling output levels of an MMC converter to reduce fluctuation in a power grid frequency, which adjusts an output level of the MMC converter in response to a change in a power grid frequency of a power grid system in the MMC converter connected to a grid system, is proposed. The method includes a detection step of detecting a power grid frequency of a grid connected to the MMC converter in real time, a comparison step of comparing the detected power grid frequency with a preset reference power grid frequency, and an adjustment step of adjusting a number of output levels of the MMC converter to reduce a difference between the detected power grid frequency and the reference power grid frequency when the detected power grid frequency and the reference power grid frequency are different from each other.

Even when a grounding capacitor is included at either end of a common mode coil, there is noise that flows from a load into a metal frame, and there is a need to restrict an amount of noise propagating to a system power supply. Because of this, a noise loop is formed of a rectifier circuit, an inverter, a first electrical wire that connects a positive polarity side of the rectifier circuit and the inverter, a second electrical wire that connects a negative polarity side of the rectifier circuit and the inverter, a ground wire terminal that can connect a load connected to an output terminal or the inverter, and a conductive plate that connects at least one or the first electrical wire and second electrical wire and the ground wire terminal.

Even when a grounding capacitor is included at either end of a common mode coil, there is noise that flows from a load into a metal frame, and there is a need to restrict an amount of noise propagating to a system power supply. Because of this, a noise loop is formed of a rectifier circuit, an inverter, a first electrical wire that connects a positive polarity side of the rectifier circuit and the inverter, a second electrical wire that connects a negative polarity side of the rectifier circuit and the inverter, a ground wire terminal that can connect a load connected to an output terminal or the inverter, and a conductive plate that connects at least one or the first electrical wire and second electrical wire and the ground wire terminal.

The present disclosure relates to power management apparatuses and systems utilizing synchronous common coupling. A power management apparatus may comprise a plurality of ports, and a plurality of electrically isolated stacks connected through a synchronous common coupling. Each electrically isolated stack may include a plurality of cascaded stages and connected to a source or load through one of the plurality of ports. The synchronous common coupling connects may only power between each of the plurality of electrically isolated stacks and is configured to maintain electrical isolation for each of the plurality of stages in the plurality of electrically isolated stacks.

The present disclosure relates to power management apparatuses and systems utilizing synchronous common coupling. A power management apparatus may comprise a plurality of ports, and a plurality of electrically isolated stacks connected through a synchronous common coupling. Each electrically isolated stack may include a plurality of cascaded stages and connected to a source or load through one of the plurality of ports. The synchronous common coupling connects may only power between each of the plurality of electrically isolated stacks and is configured to maintain electrical isolation for each of the plurality of stages in the plurality of electrically isolated stacks.

A power unit for producing both alternating current and direct current includes a switcher connected to a direct current source, wherein the switcher includes circuitry configured to produce both alternating current having first characteristics and direct current having second characteristics, wherein the circuitry comprises a plurality of insulated gate bipolar transistor circuits and drive circuits connected to the insulated gate bipolar transistor circuits. The switcher may receive variable voltage and frequency or constant voltage and frequency. In either case, the switcher circuitry is able to provide power of the desired characteristics. The power unit may be used to power aircraft when the aircraft is on the ground.