A control device (2) of an inverter converts electrical power generated by a solar cell (3) into alternating current power connecting to an electric power system (7). The control device includes: an alternating current voltage sensor (14) sensing a system voltage (Vr) of the electric power system; an MPPT executer (23) controlling a direct current voltage (Vdc) applied to the inverter (1) to cause the electrical power output from the solar cell (3) to be a maximum when the direct current voltage (Vdc) is higher than a lower limit (VL); a direct current voltage lower limit calculator 22 reducing the lower limit (VL) when the system voltage (Vr) is lower than a predetermined voltage; and an electrical power controller (25) controlling reactive power based on the system voltage (Vr), the reactive power being output from the inverter (1).

According to one embodiment, a voltage converting device includes a DC power source; an inverter generating AC power; an AC component detector configured to detect an AC component of current flowing through a first terminal or a second terminal of the inverter in the DC power source side; and a phase estimator configured to estimate a phase relation between a phase of voltage of the AC power and a phase of current of the AC power based on an amplitude of a specific frequency component contained in a first absolute value signal of the AC component. The AC power generated by the inverter is supplied to a loading device, and an impedance of the loading device at a fundamental of a driving frequency of the inverter is smaller than an impedance of the loading device at an odd-order harmonic of the driving frequency.

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.

There is obtained an electric-power conversion apparatus that prevents it that the temperature of a semiconductor switching device reaches a breakage temperature and hence the semiconductor switching device is broken and that realizes continuity of driving. The electric-power conversion apparatus includes a temperature sensor that detects a temperature of semiconductor switching device, and a temperature rising rate determination unit that compares a predetermined first threshold value with a temperature rising rate calculated based on a temperature detection value detected by the temperature sensor and determines that the temperature rising rate has exceeded the first threshold value; when the temperature rising rate determination unit determines that the temperature rising rate has exceeded the first threshold value, protective operation for suppressing an output of an electric-power conversion unit is performed.

Disclosed herein are systems and methods for low power excitation of wireless power transmitters configured to transmit high power. The exemplary systems and methods include disabling a power factor correction circuit of the transmitter, and adjusting one or more variable impedance components of the impedance network to obtain a minimum attainable impedance. The variable impedance components can be configured to operate between the minimum attainable impedance and a maximum attainable impedance. The systems and methods can include adjusting a phase shift angle associated with one or more transistors of the inverter and driving the transmitter such that the transmitter resonator coil generates a magnetic flux density less than or equal to a field safety threshold.

A power supply device includes a controller configured to output, to a power converter, a command value to control at least one of a voltage or a current of power output from the power converter, and acquire a measurement value measured by a measurement unit. The controller is configured to, while power conversion operation is being performed by the power converter, change the command value and determine a deterioration of the power converter based on a mode of a change in the measurement value measured by the measurement unit due to a change in the command value.

A powertrain for electric and plug-in hybrid vehicle applications with integrated three-phase AC charging featuring buck-boost operation and optional vehicle-to-grid (V2G) capability, along with corresponding methods and machine instruction sets for switch control. The powertrain can include of a three-phase current source converter (CSC) front-end with an associated input filter, a polarity inversion module, and in an embodiment, a dual-inverter motor drive. The dual-inverter drive is the source of both the back emf and requisite DC inductance for the CSC. A compact design is thus provided as no additional magnetics are required and the on-board cooling system required for traction mode can be re-deployed for charging and V2G mode. The powertrain is mode shifted between charging and V2G mode through an optional polarity inversion module.

A power conversion device capable of shortening the time required for acceleration of a motor and a metal processing device including the power conversion device are provided. Then, a power conversion device 10 includes a converter 100 configured to convert an AC voltage from outside to a DC voltage Vo and a converter controller 107 configured to control the converter 100. The converter 100 includes a voltage doubler circuit 104 configured to boost the DC voltage Vo when activated, and outputs the DC voltage Vo having a voltage value different in accordance with the activation and stop of the voltage doubler circuit 104. The converter controller 107 activates the voltage doubler circuit 104 at a first time that is earlier by a predetermined period than a second time at which a speed command value ω* of the motor 130 rises from a predetermined value.

Example three-level inverters, control methods, and systems are provided. One example three-level inverter includes a first bus capacitor, a second bus capacitor, a power conversion circuit, and a controller. The first bus capacitor is connected in the middle of the current bus and the power conversion circuit. The power conversion circuit is configured to convert a direct current into a three-phase alternating current for output. The controller is configured to determine a balance reference by using a difference between absolute values of voltages of the positive and negative direct current buses and an even harmonic current in a grid-connected current, where the balance reference is used to enable the three-level inverter to generate a current signal for balancing the voltages of the positive and negative direct current buses.

A rotary electric machine control apparatus (1) suitably controls two inverters (10) connected to associated ends of open windings (8). The rotary electric machine control apparatus (1) performs target control involving: controlling a first one of the inverters (10), which is selected from a first inverter (11) and a second inverter (12), by rectangular wave control; and controlling a second one of the inverters (10) by special pulse width modulation control that is one type of pulse width modulation control. The special pulse width modulation control is a control method to produce a switching pattern (Su2+) that is based on a difference between a switching pattern resulting from the pulse width modulation control and a switching pattern (Su1+) resulting from the rectangular wave control when a target voltage is to be generated in the open windings (8).