A grid connection power conversion device for connecting a distributed power supply to a three-phase commercial power system is provided. The power conversion device comprises an inverter, an instantaneous voltage detection circuitry to detect a maximum three-phase instantaneous voltage value of the commercial power system, a line voltage detection circuitry to detect a maximum value of each of three line voltages, an instantaneous voltage drop detection circuitry to detect an instantaneous voltage drop, and an output current control circuitry to control an output current value from the inverter. When the instantaneous voltage drop detection circuitry detects an instantaneous voltage drop, the output current control circuitry reduces the output current value from the inverter to an output current value corresponding to a minimum value among the four maximum voltage values which are the maximum three-phase instantaneous voltage value and the maximum values of the three line voltages.

A method for controlling a power factor correction circuit includes: sensing, by a control unit, an input signal; deriving, by the control unit, a delay correction input signal using the input signal and a previous input signal that is sensed before the input signal; and controlling, by the control unit, the power factor correction circuit using the derived delay correction input signal.

A method for controlling a power factor correction circuit includes: sensing, by a control unit, an input signal; deriving, by the control unit, a delay correction input signal using the input signal and a previous input signal that is sensed before the input signal; and controlling, by the control unit, the power factor correction circuit using the derived delay correction input signal.

A microwave generator includes a power supply, an output circuit, a feedback oscillator, a pulse controller, a signal combination circuit and a semiconductor amplifier. The power supply converts input voltage and input current into output voltage and output current. The output circuit generates a microwave signal to an output terminal of the microwave generator and a feedback signal according to the microwave signal. The feedback oscillator generates an oscillation signal according to the feedback signal. According to a reference signal, the pulse controller generates a pulse signal. According to the oscillation signal and pulse signal, the signal combination circuit generates a control signal. The semiconductor amplifier generates and adjusts an amplified signal according to the control signal. The output circuit generates the microwave signal according to the amplified signal. The output current is adjusted according to the amplified signal. Consequently, the input current and the input voltage are in phase.

A microwave generator includes a power supply, an output circuit, a feedback oscillator, a pulse controller, a signal combination circuit and a semiconductor amplifier. The power supply converts input voltage and input current into output voltage and output current. The output circuit generates a microwave signal to an output terminal of the microwave generator and a feedback signal according to the microwave signal. The feedback oscillator generates an oscillation signal according to the feedback signal. According to a reference signal, the pulse controller generates a pulse signal. According to the oscillation signal and pulse signal, the signal combination circuit generates a control signal. The semiconductor amplifier generates and adjusts an amplified signal according to the control signal. The output circuit generates the microwave signal according to the amplified signal. The output current is adjusted according to the amplified signal. Consequently, the input current and the input voltage are in phase.

There are included: generation means for generating predetermined information represented by a bit string; and control means for controlling a phase difference between current and voltage of AC power at predetermined time intervals so that each bit value included in the bit string is represented.

In a method for detecting a motor phase fault of a motor arrangement, the motor phases of which are connected to a drive circuit having a DC voltage intermediate circuit and an inverter. A motor phase voltage at at least one of the motor phases with respect to a reference potential is captured while the inverter is switched off; and a voltage profile of the captured motor phase voltage is used to determine whether there is a motor phase fault on one of the motor phases of the motor arrangement.

In order to create a full variable shunt reactor having two magnetically controllable high-voltage throttles which is compact and at the same time can also provide capacitive reactive power, auxiliary windings are used which are inductively coupled to the high-voltage throttles. The auxiliary windings are connected to at least one capacitively acting component.

In order to create a full variable shunt reactor having two magnetically controllable high-voltage throttles which is compact and at the same time can also provide capacitive reactive power, auxiliary windings are used which are inductively coupled to the high-voltage throttles. The auxiliary windings are connected to at least one capacitively acting component.

A current sensing correction method for a driving system is provided. Firstly, the detection values of a three-phase current are acquired through the measuring unit. When the three-phase current is maintained at the DC state, the DC values of the three-phase current are acquired and recorded as three-phase demagnetization values. When the detection values are zero, a d-axis current and a q-axis current are calculated according to the three-phase demagnetization values, a d-axis correction current command and a q-axis correction current command are calculated according to a proportional constant, the d-axis current and the q-axis current, and a three-phase demagnetization current is generated to the measuring unit according to the d-axis correction current command and the q-axis correction current command. When the demagnetization time reaches the first predetermined time, the three-phase demagnetization current is not generated.