A power conversion device includes, for respective phases of an AC circuit, leg circuits each having a pair of arms connected in series to each other, each arm including a plurality of converter cells which are connected in series and each of which has an energy storage element. A controlling circuitry includes a zero-phase-sequence voltage command value adjustment unit for correcting arm voltage command values for the arms by a zero-phase-sequence voltage command value. The command value correction circuitry performs adjustment control for adjusting the zero-phase-sequence voltage command value so that at least one arm voltage command value becomes equivalent to a limit value of the output voltage range of the arm.

An apparatus includes a power supply monitor operative to monitor a status of multiple power converters. Based on the monitored status, the power supply monitor detects an event associated with a first power converter of the multiple power converters. The power supply monitor communicates a notification of the event to a management entity. The notification is encoded to include an identity of the first power converter experiencing the event as determined by the power supply monitor or other suitable entity.

Components of a power amplifier controller may support lower voltages than the power amplifier itself. As a result, a surge protection circuit that prevents a power amplifier from being damaged due to a power surge may not effectively protect the power amplifier controller. Embodiments disclosed herein present an overvoltage protection circuit that prevents a charge-pump from providing a voltage to a power amplifier controller during a detected surge event. By separately detecting and preventing a voltage from being provided to the power amplifier controller during a surge event, the power amplifier controller can be protected regardless of whether the surge event results in a voltage that may damage the power amplifier. Further, embodiments of the overvoltage protection circuit can prevent a surge voltage from being provided to a power amplifier operating in 2G mode.

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.

An AC-DC power supply receives input AC power and outputs DC power. The converter includes a high power factor bridge rectifier, a barrier circuit with resistor(s) and capacitor(s), and a step-down switching DC-DC converter to step-down a first DC voltage to a second, lower, DC voltage for output. Additionally, fault-protection is provided by redundancy in diodes on diode legs of a bridge rectifier and capacitor(s) of a filter circuit thereof, and a fault-protection circuit to sense current from a step-down switching DC-DC converter, a first voltage from the step-down switching DC-DC converter, and/or a second voltage at an output of the step-down switching DC-DC converter, and open the circuit on a fault.

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.

Described is a supply circuit for a corona ignition device, with an input for connection to a direct voltage source, a first converter, a second converter, and an output for connecting a load. The two converters each generate an output voltage, which is provided on its secondary side and exceeds the input voltage. The two converters each contain a transformer that galvanically separates the primary side of the converter from its secondary side. At least one transistor switch is arranged between the input and primary side of the two converters for pulse width-modulation of the input voltage. The primary side of the second converter is connected in parallel with the primary side of the first converter, the secondary side of the second converter is connected in series with the secondary side of the first converter, the secondary sides of the two converters are each bridged in this series connection by at least one diode, so that an output voltage can be provided at the output of the supply circuit even given a failure of one of the two converters.

Disclosed are an inverter control device and method. The method according to an embodiment of the present includes estimating a rotation speed of a motor, determining a slip frequency reference using an energy of a direct current terminal capacitor of an inverter, which provides an output voltage to the motor, and a direct current terminal energy reference when a direct current terminal voltage of the inverter is a certain level or less, and providing a frequency reference determined by adding the rotation speed of the motor and the slip frequency reference to the inverter.

A loss optimization control method for modular multilevel converters (MMCs) under fault-tolerant control is disclosed. The method includes the following steps: when a fault of a SM in a MMC occurs, bypassing the faulty SM to achieve fault-tolerant control; suppressing the fundamental circulating current using a fundamental circulating current controller; respectively calculating the loss of each SM in faulty arms and healthy arms by using loss expressions of different switching tubes in SMs of the MMC; aiming at the loss imbalance between the arms of the MMC, taking the loss of a healthy SM as the reference, adjusting the period of capacitor voltage sorting control in the faulty SMs, achieving the loss control over the working SMs in the faulty SMs, and finally achieving the loss balance of each SM in the faulty arms and the healthy arms. Compared with the conventional methods, the proposed method is easier to implement and does not increase the construction cost of MMCs.

An electric power conversion control apparatus includes: a first converter of the first electric power conversion control apparatus and a second converter of the second electric power conversion control apparatus, which feed electric power to a first winding wire and a second winding wire of a dual three-phase motor; a first controller and a second controller, which control the first converter and the second converter; a communication line, which is connected between the first controller and the second controller; and a fifth signal wire for deactivating the operation of the second converter, from the first controller. When a fault is caused by communication errors, the first controller uses the fifth signal wire to deactivate the operation of the second converter, and the electric power conversion control apparatus switches to one system operation by the first controller.