Control systems for a multi-level diode-clamped inverter and corresponding methods include a processor and a digital logic circuit forming a hybrid controller. The processor identifies sector and region locations based on a sampled reference voltage vector V* and angle θ.sub.e*. The processor then selects predefined switching sequences and pre-calculated turn-on time values based on the identified sector and region locations. The digital logic circuit generates PWM switching signals for driving power transistors of a multi-level diode-clamped inverter based on the turn-on time values and the selected switching sequences. The control system takes care of the existing capacitor voltage balancing issues of multi-level diode-clamped inverters while supplying both active and reactive power to an IT load. Using the control system, one can generate a symmetrical PWM signal that fully covers the linear under-modulation region.

According to at least one aspect of the disclosure, an inverter is provided comprising an input configured to receive input DC power from a DC source, an output configured to provide output AC power to a load, a plurality of DC rails coupled to the input and configured to receive the input DC power from the DC source, a plurality of switches coupled between the plurality of DC rails and configured to convert the input DC power into the output AC power, each switch of the plurality of switches having a parasitic capacitance, and at least one ZVS network coupled across at least two switches of the plurality of switches, the ZVS network including at least two inductors configured to resonate with the parasitic capacitance of at least one switch of the plurality of switches to provide soft switching of at least one switch of the plurality of switches.

A method for improving an autonomous microgrid, and an autonomous microgrid that includes a plurality of inverter-based distributed generations. Each of the inverter-based distributed generations is coupled to a corresponding power droop controller, a corresponding voltage controller, and a corresponding current controller. The autonomous microgrid further includes a constant power load (CPL) coupled to one of the plurality of inverted-based distributed generations. The CPL includes a phase locked loop (PLL), a DC voltage controller and an AC current controller. Power-sharing coefficients, controller parameters of the controllers and gains of the PLL are defined based on a weighted objective function that is calculated through on a particle swarm optimization.

A power conversion apparatus includes: an inverter to drive a motor, using a first carrier signal; an inverter connected in parallel to the inverter, to drive a motor, using a second carrier signal; respective phase lower arm shunt resistors to detect a first current flowing inside the inverter; respective phase lower arm shunt resistors to detect a second current flowing in the inverter; and a control unit to control the inverters. A phase difference is set between the first carrier signal and the second carrier signal to prevent a detection period for the first current in the first carrier signal and a detection period for the second current in the second carrier signal from overlapping each other when the inverters are controlled.

A rotation controller for an AC electric motor includes a space vector generator, a current change ratio obtainer, and a rotational angle calculator. The space vector generator generates at least a first magnetic field in a first direction and a second magnetic field in a second direction crossing the first direction in a rotation plane of a saliency-exhibiting rotor. The space vector generator synthesizes the first magnetic field and the second magnetic field into a synthesized magnetic field. The current change ratio obtainer acquires a first current change ratio of a first current generated in the first direction in a stator and a second current change ratio of a second current generated in the second direction in the stator. The rotational angle calculator calculates a rotational angle of the saliency-exhibiting rotor based on at least the first and second current change ratios and the first and second directions.

A system for protecting an inverter in a vehicle from an overvoltage may include an inverter including a plurality of switching elements and converting energy supplied from an energy storage into AC power, a motor driven by the AC power converted by the inverter, a capacitor connected in parallel between the inverter and the energy storage and storing regenerative energy of the motor during regenerative braking, and a controller turning off a relay that connects the energy storage and the motor, when a voltage (DC-link voltage) of the capacitor measured by a voltage sensor is equal to or greater than a preset first voltage, and operating the switching elements in the inverter in response to a pre-stored current command (Id*, Iq*) to apply a zero vector to the motor.

The drive controller for the electric motor according to the present invention comprises two drive control systems for two winding sets of the electric motor, each drive control system includes a control circuit, an inverter, a power supply connector and a ground connector, the two control circuits are connected to an internal common ground, each rectifying element that passes a current from the common ground to each ground connector is provided in a line that connects the ground connector and the common ground, each current detection element is provided in a line that connects each positive power supply and a line between the rectifying element and the ground connector, and whether an open fault has occurred in the ground connector is diagnosed based on the voltage that is applied to the current detection element.

A power device for an electrical applicant, such as, a household air conditioner, is provided. The power device has a control input terminal, a first driving circuit, and a second driving circuit. When the control input terminal inputs a low level, the first driving circuit and the second driving circuit output high and low level signals in a first voltage range. When the control input terminal inputs a high level, the first driving circuit and the second driving circuit output high and low level signals in a second voltage range. The first voltage range is different from the second voltage range.

The present disclosure relates to a method for controlling a converter, in particular power converter of a wind power installation. The converter has a plurality of, preferably parallel, converter modules. The method includes the following steps: driving a first converter module, such that the converter module generates a first electrical AC current in a first switch position, driving a second converter module, such that the converter module generates a second electrical AC current in a second switch position, superposing the first electrical AC current and the second electrical AC current to form a total current, detecting the total current of the converter, determining a virtual current depending on the first and second switch positions, and changing the first switch position of the first converter module and/or the second switch position of the second converter module depending on the total current and the virtual current.

An object of the present invention is to provide a power conversion device capable of reliably discharging a voltage smoothing capacitor even when a circuit unit that outputs a discharge control signal fails. The power conversion device includes a voltage smoothing capacitor that is electrically connected in parallel with an inverter circuit unit, a discharge resistor that is electrically connected in parallel with the voltage smoothing capacitor, a switching element that is connected in series with the discharge resistor, a motor controller that selectively outputs a High-level signal and a Low-level signal as a discharge control signal, a switching signal circuit unit that outputs a rectangular wave signal having a predetermined duty, and a logic circuit that outputs any one of a rectangular wave signal having the same duty as the duty of the rectangular wave signal and a rectangular wave signal having a duty to the switching element based on the discharge control signal and the rectangular wave signal.