Abstract:
A control circuit for a motor of a compressor includes an inverter control module configured to control power switching devices of an inverter to generate output voltages from a DC power supply. The output voltages are applied to windings of the motor. A current control module is configured to generate voltage signals based on a torque demand. The inverter control module controls the power switching devices according to the voltage signals. A selector is configured to output one of an open loop torque value and a closed loop torque value as the torque demand. An open loop torque module is configured to generate the open loop torque value. The open loop torque module is configured to apply an upper limit to the open loop torque value. The upper limit is based on a voltage of the DC power supply.
Abstract:
AC motor driving system and driving method thereof are provided. The driving system and method are capable of increasing power factor, adjusting waveform of the DC ripple voltage for increasing driving efficiency. The driving system is basically constructed by connecting three circuits. The first circuit is a three-phase full wave rectifying circuit and is used to transfer commercial electricity to a first DC voltage. Then, the second circuit is used to transfer the first DC voltage to a second DC voltage that ripples voltage thereof having a semi-sinusoidal waveform. The third circuit is an AC driving circuit, and receives the second AC voltage for driving the AC motor. Thereby, the driving efficiency can be increased. The capacitance used in the present disclosure has low capacitance value, thus the power factor can be increased, and usage time of the AC motor driving apparatus can also be increased.
Abstract:
A diode bridge has a pair of input ends to which an alternating current is inputted from an AC power supply, and a pair of output ends which output a direct current. A boost chopper circuit is connected to the pair of output ends, and sets up a DC voltage inputted thereto. The boost chopper circuit functions as a power factor correction circuit. A smoothing capacitor is connected to an output side of the boost chopper circuit, and smoothes the voltage across the smoothing capacitor. An inverter receives the voltage across the smoothing capacitor to apply AC power to a load. A leakage current reduction device outputs a compensating current which compensates for a leakage current leaking from the load. The leakage current reduction device outputs the compensating current, except near the zero crossing of an AC voltage inputted from the AC power supply.
Abstract:
A drive circuit is provided for reducing conducted electromagnetic interference provided by a power line to a motor controller. The drive circuit includes an EMI filter having first and second EMI filter input terminals, and first and second EMI filter output terminals. The first input terminal is configured to be coupled to a first AC line output and the second input terminal is configured to be coupled to a second AC line output. The drive circuit includes a rectifier portion having first and rectifier input terminals coupled to the first and second EMI output terminals, respectively. The drive circuit includes at least two series-coupled filter capacitors after the rectifier portion and a PFC choke coupled at a first end to one of the EMI filter output terminals and to one of the first and second rectifier input terminals, and at a second end between the series-coupled filter capacitors.
Abstract:
A current control module generates a voltage request based on a d-axis current (Idr) demand. A switching control module controls a motor based on the voltage request and generates an out-of-volts (OOV) signal based on a comparison of the voltage request and an available voltage. An Idr injection module generates the Idr demand based on a direct current (DC) bus voltage, a rotational speed, and a demanded torque and selectively applies a first adjustment to the Idr demand. The Idr injection module identifies whether an improvement resulted from the first adjustment, wherein the improvement is identified based on at least one of (i) a measured current of the motor and (ii) the OOV signal. The Idr injection module selectively applies a second adjustment to the Idr demand based on whether the improvement is identified.
Abstract:
An object is to improve the accuracy of power factor adjustment. Power-factor command values corresponding to individual wind turbines are determined by correcting a predetermined power-factor command value for an interconnection node using power factor correction levels set for the individual wind turbines.
Abstract:
A control system for a motor includes a pulse-width modulation module, a pulse skip determination module, and a duty cycle adjustment module. The pulse-width modulation module generates three duty cycle values based on three voltage requests, respectively. A plurality of solid-state switches control three phases of the motor in response to the three duty cycle values, respectively. The pulse skip determination module generates a pulse skip signal. The duty cycle adjustment module selectively prevents the plurality of solid-state switches from switching during intervals specified by the pulse skip signal.
Abstract:
An object is to improve the accuracy of reactive power adjustment. Reactive-power command values corresponding to individual wind turbines are determined by correcting a predetermined reactive-power command value for an interconnection node A using reactive power correction levels set for the individual wind turbines.
Abstract:
A motor control system includes a control module, a switching module, and a filtering module. The control module determines output voltages for operating a motor based on a torque demand. The switching module generates switching signals for an inverter that drives the motor. The switching module generates the switching signals based on the output voltages. The switching module generates an out-of-volts (OOV) signal according to a comparison based on the output voltages, a maximum duty cycle, and a voltage of a direct current (DC) bus that provides power to the inverter. The filtering module generates an OOV amount by filtering the OOV signal. The control module selectively limits the torque demand based on the OOV amount.
Abstract:
An active rectifier controller controls operation of an active rectifier employed in a power conversion system that supplies a direct current (DC) output to an inverter that converts the DC output to an AC output supplied to an AC motor. The active rectifier controller includes a field-oriented control (FOC) controller that monitors an alternating current (AC) input currents provided to the active rectifier, the DC output provided to the inverter, and speed of the AC motor. The FOC controller selects a reference DC output value based on the speed of the AC motor and compares the monitored DC output to the reference DC output as part of the FOC control algorithm used to generate control signals. A PWM signal generator generates PWM signals for controlling the active rectifier based on the control signals.