Abstract: In one aspect, a method for protecting one or more electrical machines during a grid fault on an electrical system connected with the one or more electrical machines is provided. The method includes detecting a grid fault on an electrical system; taking one or more first actions from a first set of actions based on detected grid fault on the electrical system; detecting at least one operating condition of the electrical system after taking one or more first actions from the first set of actions based on the detected grid fault on the electrical system; and taking one or more second actions from a second set of actions based on the detected at least one operating condition of the electrical system.

Abstract: A power conversion system is disclosed including a DC bus for receiving DC power, a power converter for converting the DC power to AC power, and a controller. The controller includes an active power regulator for generating a phase angle command signal, a reactive power regulator for generating a voltage magnitude command, and an active power (P) and reactive power (Q) decoupling unit for decoupling interaction between the active and reactive power regulators. The PQ decoupling unit includes an active power compensation element and a reactive power compensation element. The active power compensation element is used for generating a phase angle compensation signal based on a reactive power error signal, to compensate the phase angle command signal. The reactive power compensation element is used for generating a voltage magnitude compensation signal based on an active power error signal, to compensate the voltage magnitude command signal.

Abstract: An exemplary power conversion system comprises an MPPT unit, a DC bus, a power converter, and a converter controller. The MPPT unit receives a feedback current signal and a feedback voltage signal from a power source and generates an MPPT reference signal based at least in part on the feedback current and voltage signals. The DC bus receives DC power from the power source. The power converter converts the DC power on the DC bus to AC power. The converter controller receives the MPPT reference signal from the MPPT unit and an output power feedback signal measured at an output of the power converter; generates control signals for AC power regulation and maximum power extraction based at least in part on the MPPT reference signal and the output power feedback signal; and sends the control signals to the power converter.

Abstract: A power conversion system is disclosed including a DC bus for receiving DC power, a power converter for converting the DC power to AC power, and a controller. The controller includes an active power regulator for generating a phase angle command signal, a reactive power regulator for generating a voltage magnitude command, and an active power (P) and reactive power (Q) decoupling unit for decoupling interaction between the active and reactive power regulators. The PQ decoupling unit includes an active power compensation element and a reactive power compensation element. The active power compensation element is used for generating a phase angle compensation signal based on a reactive power error signal, to compensate the phase angle command signal. The reactive power compensation element is used for generating a voltage magnitude compensation signal based on an active power error signal, to compensate the voltage magnitude command signal.

Abstract: An exemplary power conversion system is disclosed including a DC bus for receiving DC power; a line side converter electrically coupled to the DC bus for converting the DC power to AC power; and a voltage source controller to provide control signals to enable the line side converter to regulate the AC power. The voltage source controller comprises a signal generator to generate the control signals based at least in part on a power command signal and a power feedback signal. The voltage source controller further comprises a current limiter to, during a transient event, limit the control signals based at least in part on an electrical current threshold. The voltage source controller further comprises a voltage limiter to, during the transient event, limit the control signals based at least in part on a DC bus voltage feedback signal and a DC boundary voltage threshold.

Abstract: A system and method are provided for performing reactive power control. The system includes a power converter and a controller coupled to the power converter. The power converter is configured to convert a first form of electric power generated from the power source to a second form of electric power suitable to be distributed by the electrical grid. The controller is configured to monitor the electric power transmitted between the power converter and the electrical grid. The controller is further configured to decouple a positive sequence component and a negative sequence component from the monitored electric power. The controller is further configured to perform a positive reactive power control and a negative reactive power control with respect to the decoupled positive and negative sequence components. The controller is further configured to transmit a control signal to the power converter based on the positive and negative reactive power control.

Abstract: Embodiments of the invention relate to a power system for converting direct current (“DC”) power on a DC bus into alternating current (“AC”) power with a regulated voltage output and for feeding the AC power to an electrical system which may include a power utility or an electric grid, for example. A power conversion control system is used for controlling the power conversion and for maintaining the DC bus voltage (“DC voltage”) at a certain level.

Abstract: A converter system comprises a DC to AC converter, a maximum power point tracking device, and an array-side control. The DC link converts DC from a photovoltaic array to AC for a grid. The maximum power point tracking device is coupled to the array. The array-side control, which is coupled to the DC to AC converter and the device, prevents overvoltage in the DC bus of the DC to AC converter using array voltage and current data from the device and DC bus voltage data from the DC to AC converter during a grid transient by adjusting a maximum power point of the array to increase array voltage.

Abstract: A system and method are provided for performing reactive power control. The system includes a power converter and a controller coupled to the power converter. The power converter is configured to convert a first form of electric power generated from the power source to a second form of electric power suitable to be distributed by the electrical grid. The controller is configured to monitor the electric power transmitted between the power converter and the electrical grid. The controller is further configured to decouple a positive sequence component and a negative sequence component from the monitored electric power. The controller is further configured to perform a positive reactive power control and a negative reactive power control with respect to the decoupled positive and negative sequence components. The controller is further configured to transmit a control signal to the power converter based on the positive and negative reactive power control.

Abstract: 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.

Abstract: An exemplary power conversion system comprises an MPPT unit, a DC bus, a power converter, and a converter controller. The MPPT unit receives a feedback current signal and a feedback voltage signal from a power source and generates an MPPT reference signal based at least in part on the feedback current and voltage signals. The DC bus receives DC power from the power source. The power converter converts the DC power on the DC bus to AC power. The converter controller receives the MPPT reference signal from the MPPT unit and an output power feedback signal measured at an output of the power converter; generates control signals for AC power regulation and maximum power extraction based at least in part on the MPPT reference signal and the output power feedback signal; and sends the control signals to the power converter.

Abstract: An exemplary power conversion system is disclosed including a DC bus for receiving DC power; a line side converter electrically coupled to the DC bus for converting the DC power to AC power; and a voltage source controller to provide control signals to enable the line side converter to regulate the AC power. The voltage source controller comprises a signal generator to generate the control signals based at least in part on a power command signal and a power feedback signal. The voltage source controller further comprises a current limiter to, during a transient event, limit the control signals based at least in part on an electrical current threshold. The voltage source controller further comprises a voltage limiter to, during the transient event, limit the control signals based at least in part on a DC bus voltage feedback signal and a DC boundary voltage threshold.

Abstract: Embodiments of the invention relate to a power system for converting direct current (“DC”) power on a DC bus into alternating current (“AC”) power with a regulated voltage output and for feeding the AC power to an electrical system which may include a power utility or an electric grid, for example. A power conversion control system is used for controlling the power conversion and for maintaining the DC bus voltage (“DC voltage”) at a certain level.

Abstract: A method of controlling electrical power systems coupled to an electrical connection point includes obtaining carrier signals and fundamental waveforms from electrical power systems coupled to at least two renewable energy sources, generating pulse width modulation (PWM) signals using the carrier signals and the fundamental waveforms while interleaving carrier signals, fundamental waveforms, or a combination of carrier signals and fundamental waveforms of the electrical power systems, and driving grid side converters of the electrical power systems with the PWM signals.

Abstract: A power conversion system comprises a power converter comprising a plurality of semiconductor power switches, an LC filter coupled between an output of the power converter and an electric grid, and a power conversion control system. The LC filter comprises an inductor coupled in series to the electric grid, and a capacitor. The LC filter and the grid result in an equivalent LC circuit comprising an impedance of the LC filter and an impedance of the electric grid. The power conversion control system comprises a damper and a converter controller. The damper receives an LC filter signal and an equivalent LC circuit impedance signal and generates a damping signal. The converter controller receives a current or voltage reference signal, a current or voltage command signal, and the damping signal to generate control signals for driving switching operations of the semiconductor power switches.

Abstract: A power conversion system comprises a power converter comprising a plurality of semiconductor power switches, an LC filter coupled between an output of the power converter and an electric grid, and a power conversion control system. The LC filter comprises an inductor coupled in series to the electric grid, and a capacitor. The LC filter and the grid result in an equivalent LC circuit comprising an impedance of the LC filter and an impedance of the electric grid. The power conversion control system comprises a damper and a converter controller. The damper receives an LC filter signal and an equivalent LC circuit impedance signal and generates a damping signal. The converter controller receives a current or voltage reference signal, a current or voltage command signal, and the damping signal to generate control signals for driving switching operations of the semiconductor power switches.

Abstract: A method of controlling electrical power systems coupled to an electrical connection point includes obtaining carrier signals and fundamental waveforms from electrical power systems coupled to at least two renewable energy sources, generating pulse width modulation (PWM) signals using the carrier signals and the fundamental waveforms while interleaving carrier signals, fundamental waveforms, or a combination of carrier signals and fundamental waveforms of the electrical power systems, and driving grid side converters of the electrical power systems with the PWM signals.

Abstract: 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.

Abstract: A power generation system comprises at least two electrical systems connected at an electrical connection point. Each electrical system comprises a power conversion system comprising a converter including a plurality of switches for converting direct current power into alternating current power. The power generation system comprises a control system including at least two pulse width modulation (PWM) modulators, each PWM modulator for obtaining a fundamental waveform and a carrier signal, using the fundamental and carrier signals to generate a PWM pattern, and for providing the PWM pattern to a respective converter for driving the switches of the respective converter. The control system is configured to interleave carrier signals, fundamental waveforms, or a combination of carrier signals and fundamental waveforms of the at least two electrical systems to generate interleaved PWM patterns respectively for the at least two converters.

Abstract: A system for controlling torque ripple in a permanent magnet synchronous machine includes a power converter configured to be coupled to the permanent magnet synchronous machine and to receive converter control signals and a system controller coupled to the power converter. The system controller includes a fundamental current controller configured for providing fundamental voltage commands, a harmonic current controller configured for using harmonic current commands, current feedback signals from the permanent magnet machine, and fundamental current commands in combination with positive and negative sequence regulators to obtain harmonic voltage commands, and summation elements configured for adding the fundamental voltage commands and the harmonic voltage commands to obtain the converter control signals.