A control device (8) for an inverter (2) that feeds an electric machine (3), wherein the control device (8) is configured to provide pulse-width-modulated switching signals (15) at a carrier frequency to drive switching elements (12) of the inverter (2), wherein the control device (8) is configured to ascertain the carrier frequency within at least one operating range (22, 23) depending on a piece of operating point information that describes an operating point defined by a rotation speed and a torque of the electric machine (3) in such a way that the carrier frequency is reduced within the at least one operating range (22, 23) compared to a maximum carrier frequency operating point at which a maximum carrier frequency is specified in the operating range.

A motor driving device includes a direct current (DC) link capacitor configured to store DC power, and an inverter configured to convert the DC power stored in the DC link capacitor into AC power and supply the AC power to a motor. The motor driving device includes a shunt resistor configured to sense current flowing through the inverter and detect whether the current has reached threshold current for controlling a regenerative voltage during a braking operation. A control unit is configured to control an operation of the inverter and perform a regenerative operation when the braking operation is started. The control unit, during the regenerative operation, switches motive power of a drum connected to the motor into regenerative energy and transmit the regenerative energy to the DC link capacitor, by controlling active component current and reactive component current together in response to the reaching of the threshold current.

A DFIG power system defines a generator power path and a converter power path. The generator power path has a DFIG with a rotor and a stator. The converter power path has a power converter with a rotor-side converter coupled to a line-side converter via a DC link. The power converter has at least two power bridge circuits connected in parallel. A method of operating the DFIG power system includes monitoring, via one or more sensors, at least one electrical condition thereof. The method also includes comparing, via a control system, the at least one electrical condition to a predetermined threshold, the predetermined threshold being indicative of an occurrence of a transient overloading event. Further, the method includes alternating between non-interleaving and interleaving intervals if the at least one electrical condition exceeds the predetermined threshold so as to reduce harmonics of the DFIG power system.

A power converter system comprising a power source; a plurality of voltage source converters for driving respective loads; the plurality of voltage converters connected to the power source via a common DC-link, control means (10a, 10b) for driving the voltage source converters by means of respective control signals modulated onto respective modulation carriers; and means for synchronizing the control means such that the respective modulation carriers are interleaved with a selected phase shift therebetween.

A system for reducing a resonant oscillation on a direct current bus of a power inverter/converter for an electric machine having a variable frequency drive is disclosed. The system includes a battery, a first capacitor connected in parallel with the battery; an inductor connected in series with the first capacitor; a first diode connected in series with the inductor; a second diode connected in parallel with the inductor and the first diode; a second capacitor connected in series with the first diode; and a starter-generator connected to the second capacitor. During a re-generation mode for charging the battery, a re-generation current flows from the starter-generator to the battery, passing through the first diode and the inductor and bypassing the second diode. During a motor mode, a motor current flows from the battery to the starter-generator, passing through the second diode and bypassing the first diode and the inductor.

A connection member includes: a first short bar whose one end is attached to a first terminal block; a second short bar which extends in a longitudinal direction of the first short bar and whose one end is attached to a second terminal block, at least part of the other end of the second short bar overlapping the first short bar; and a guide member which is attached to an overlapping part of the first short bar and the second short bar and which allows the second short bar to move relative to the first short bar in the longitudinal direction while maintaining surface contact between the first short bar and the second short bar at the overlapping part.

A connection member includes: a first short bar whose one end is attached to a first terminal block; a second short bar which extends in a longitudinal direction of the first short bar and whose one end is attached to a second terminal block, at least part of the other end of the second short bar overlapping the first short bar; and a guide member which is attached to an overlapping part of the first short bar and the second short bar and which allows the second short bar to move relative to the first short bar in the longitudinal direction while maintaining surface contact between the first short bar and the second short bar at the overlapping part.

A thyristor starting device includes: a converter which converts AC power supplied from an AC power source into DC power; a DC reactor which smooths a DC current; an inverter which converts the DC power provided from the converter into AC power, and supplies the AC power to a synchronous machine; a gate pulse generation circuit which generates a gate pulse to be provided to thyristors of the converter and the inverter; a control unit which sets a phase control angle of the gate pulse to be provided to the thyristors of the converter, by controlling a current of the converter such that the DC current flowing into the DC reactor matches a current command value; and an abnormality detection unit which compares a detection value of the DC current with the current command value, and determines an abnormality in the gate pulse based on a comparison result.

A controller associated with a power supply determines a first ratio value. The first ratio value may be a ratio of a second time duration with respect to a first time duration, where the second time duration is a measured time duration associated with demagnetizing of a transformer in a first control cycle. The first time duration may be a measured time duration of activating a first switch in the first control cycle, where activation of the first switch operative to control a magnitude of primary current through a primary winding of the transformer. For second control cycle occurring subsequent to the first control cycle, the controller calculates an ON-time duration for activating the second switch based on the determined first ratio value.

A circuit for vector control includes a shifting pattern selector, a shifting signal generator, and driver circuitry. The shifting pattern selector is configured to select, based on a hysteresis value, an angle of a current voltage reference, and an angle of a previous voltage reference, a first shifting pattern from a plurality of shifting pattern. The shifting signal generator is configured to generate, based on the selection of the first shifting pattern and the current voltage reference, a first pulse modulated signal for a first phase and a second pulse modulated signal for a second phase. The driver circuitry is configured to control switching circuitry to generate, based on the first pulse modulated signal, a first phase signal for the first phase and to generate, based on the second pulse modulated signal, a second phase signal for the second phase.