摘要:
A phase-locked loop circuit comprises a phase error detector for receiving a multi-phase reference signal and a synchronized phase signal of the phase-locked-loop circuit, and for performing a rotational transformation to convert the multi-phase reference signal into two-phase quantities at a synchronous rotation d-q reference frame. A monotonic transfer module receives the two-phase quantities, and generates a monotonic phase error signal which is monotonic when a phase difference between the multi-phase reference signal and the synchronized phase signal ranges from −180 degrees to 180 degrees. A regulator receives the monotonic phase error signal, and generates a synchronized rotation frequency. An integrator receives the synchronized rotation frequency, and generates the synchronized phase signal.
摘要:
A power distribution system comprises a power conversion module for performing power conversion between a DC voltage at a DC side and an AC power at an AC side, and a conversion control system. The AC side of the power conversion module is electrically coupled to a grid. The conversion control system includes a phase-locked-loop circuit for receiving a multi-phase reference signal of a grid voltage and for generating a synchronized signal, a regulator for receiving reference commands, a two-phase grid feedback signal, and the synchronized signal and for generating a control signal for the power conversion module, and a phase compensation circuit for receiving the synchronized signal and the multi-phase reference signal of the grid voltage, for obtaining a phase displacement signal, and for generating a phase compensation signal for compensating the reference commands or for compensating the synchronized signal when the phase displacement signal exceeds a threshold value.
摘要:
A system for power conversion includes a power converter having switching elements, a detector, and a controller is provided. The detector detects a parameter and provides electrical signals indicative of the parameter. The controller receives the electrical signals transmitted from the detector, and sends commands to instruct the power converter to perform power conversion by operating the switching elements in accordance with switching signals at a different frequency in response to a detection of the system condition. A method for operating the system is also provided.
摘要:
An apparatus for rapidly tracking fundamental frequency information in the signal of an electric grid is a cross-coupled phase-lock loop filter (CCPLL) that includes the use of a phase-lock-loop (PLL) apparatus having a plurality individual filters, wherein an input for a first filter in the plurality of individual filters comprises the signal of the electric grid and an output signal from at least a second filter in the plurality of individual filters. A method for using the CCPLL includes applying a signal to the CCPLL and monitoring the output of the CCPLL. Use of the CCPLL may be accomplished or modeled via computer instructions stored on machine readable media.
摘要:
A system and method for controlling cross current in an interleaved power converter system having a plurality of converter threads coupled in parallel includes collecting a feedback current from each thread and obtaining a normal current and a differential mode current for each thread, based on its respective feedback current. The normal current of each thread is regulated to a commanded thread normal current value via a respective normal current control loop based on d-q rotating frame parameters. A differential mode cross current of each thread is regulated to zero via a respective differential mode cross current control loop based on d-q rotating frame parameters; while a differential mode cross current DC offset of each thread is regulated to zero via a respective differential mode cross current control loop based on stationary frame parameters.
摘要:
A system for controlling a grid connected power generating system is provided. The system includes a wind turbine, a converter, a first controller and a second controller. The wind turbine supplies electrical power to a power grid and the converter couples the wind turbine to the power grid. The first controller calculates voltage commands to emulate a phasor back electromotive force behind an inductance. The controller further generates converter switching commands from the voltage commands. The voltage commands include a voltage magnitude reference and an internal frequency reference calculated from a power imbalance between an active power reference and the electrical power. The second controller is used to limit a converter current.
摘要:
A protection system and a protection method are provided for protecting a double fed induction generator and a gearbox during a grid fault. The protection system includes a plurality of controlled impedance devices. Each of the controlled impedance devices is coupled between a respective phase of a stator winding of the double fed induction generator and a respective phase of a grid side converter. The protection system also includes a controller configured for coupling and decoupling impedance in one or more of the plurality of controlled impedance devices in response to changes in at least one of a utility grid voltage and a utility grid current.
摘要:
A protection system and a protection method are provided for protecting a double fed induction generator and a gearbox during a grid fault. The protection system includes a plurality of controlled impedance devices. Each of the controlled impedance devices is coupled between a respective phase of a stator winding of the double fed induction generator and a respective phase of a grid side converter. The protection system also includes a controller configured for coupling and decoupling impedance in one or more of the plurality of controlled impedance devices in response to changes in at least one of a utility grid voltage and a utility grid current.
摘要:
A power converter system for supplying an output voltage is provided. The power converter system is adapted to operate in a normal mode and a fault mode. The system comprises a plurality of bridges and a plurality of transformers. The system further comprises a plurality of dc link capacitors, each coupled across a corresponding bridge. The system also includes a controller adapted for, during the normal mode, switching each bridge with a respective normal phase shift. During the fault mode, the controller is adapted for switching each of the remaining ones of the bridges with a respective adjusted phase shift to generate the output voltage. During the fault mode, at least one of the plurality of bridges is bypassed.
摘要:
A power distribution system comprises a power conversion module for performing power conversion between a DC voltage at a DC side and an AC power at an AC side, and a conversion control system. The AC side of the power conversion module is electrically coupled to a grid. The conversion control system includes a phase-locked-loop circuit for receiving a multi-phase reference signal of a grid voltage and for generating a synchronized signal, a regulator for receiving reference commands, a two-phase grid feedback signal, and the synchronized signal and for generating a control signal for the power conversion module, and a phase compensation circuit for receiving the synchronized signal and the multi-phase reference signal of the grid voltage, for obtaining a phase displacement signal, and for generating a phase compensation signal for compensating the reference commands or for compensating the synchronized signal when the phase displacement signal exceeds a threshold value.