Abstract: A phase angle detector with a PLL, a power converter, and a method for reducing offsets in an input signal, in which an adaptive offset processor selectively removes a DC offset component from the input signal to generate a modified signal including a fundamental frequency component and higher order harmonics of the input signal with the DC offset component removed, and the PLL provides a phase angle signal at least partially according to the modified signal.

Abstract: A phase angle detector with a PLL, a power converter, and a method for reducing offsets in an input signal, in which an adaptive offset processor selectively removes a DC offset component from the input signal to generate a modified signal including a fundamental frequency component and higher order harmonics of the input signal with the DC offset component removed, and the PLL provides a phase angle signal at least partially according to the modified signal.

Abstract: Methods and apparatus are presented for unintentional islanding detection for grid tie converters in which the phase angle disturbance is introduced by modification of grid side converter switching control signals and a mismatch of reactive power between generation and the grid load is formed upon the occurrence of unintentional islanding, where the applied phase disturbance is determined according to two pre-defined curves to form an equivalent positive feedback at different frequencies to prevent the converter from forming an island at a new stable frequency after the grid is disconnected.

Abstract: The present techniques include methods and systems for operating converter to maintain a lifespan of the converter. In some embodiments, the operating frequency of the converter may be increased such that stress may be reduced on the bond wires of the converter. More specifically, embodiments involve calculating the aging parameters for certain operating conditions of the converter operating in a maximum power point tracking (MPPT) mode and determining whether the MPPT operation results in aging the converter to a point which reduces the converter lifespan below a desired lifespan. If the MPPT operation reduces the converter lifespan below the desired lifespan, the frequency of the converter may be increased such that the converter may be controlled to operate at a percentage of MPPT. Thus, in some embodiments, power output may be optimized with respect to maintaining a desired lifespan of the converter.

Abstract: Methods and systems for tracking an electronic signal corresponding to an operating frequency of an electronic component are provided. A method may include sampling the signal to determine previous and current time samples of the signal. A frequency of interest in the signal may also be pre-warped to decrease adverse warping effects resulting from processing signals having relatively higher operating frequencies. The previous and current time samples of the signals, along with the pre-warped frequency of interest, may be input into a digital tracking filter. The digital tracking filter may be configured to execute one or more algorithms on the previous and current time samples and the pre-warped frequency of interest to estimate a current operating frequency.

Abstract: Methods and systems for synchronizing an electric grid having unbalanced voltages are provided. A voltage vector may be filtered in a quadrature tracking filter (QTF) to generate a quadrature signal. The inputs to the QTF may be either single input, multiple outputs, or alternatively, multiple inputs, multiple outputs. Furthermore, the second state of either of the two QTF transformations may be either positive or negative. A phase-locked-loop (PLL) operation may be performed on the quadrature signal to monitor a voltage vector between the grid and a connected power converter. The QTF and PLL methods are suitable for either single-phase applications or n-phase (any number of phases) applications.

Abstract: The present techniques include methods and systems for operating converter to maintain a lifespan of the converter. In some embodiments, the operating frequency of the converter may be increased such that stress may be reduced on the bond wires of the converter. More specifically, embodiments involve calculating the aging parameters for certain operating conditions of the converter operating in a maximum power point tracking (MPPT) mode and determining whether the MPPT operation results in aging the converter to a point which reduces the converter lifespan below a desired lifespan. If the MPPT operation reduces the converter lifespan below the desired lifespan, the frequency of the converter may be increased such that the converter may be controlled to operate at a percentage of MPPT. Thus, in some embodiments, power output may be optimized with respect to maintaining a desired lifespan of the converter.

Abstract: Multiple inverter motor drives are interconnected in parallel to provide a common output to a motor. Common control circuitry is coupled to all parallel drives via optical cables and provides signals to power layer circuitry of each inverter for generation, at the power layer, of timing for gate drive signals for the respective inverter power electronic switches. The resulting timing exhibits a high degree of synchronicity such that very little imbalance occurs in the outputs of the paralleled drives, resulting in very low circulating currents.

Abstract: Methods and systems for synchronizing an electric grid having unbalanced voltages are provided. A voltage vector may be filtered in a quadrature tracking filter (QTF) to generate a quadrature signal. A phase-locked-loop (PLL) operation may be performed on the quadrature signal to monitor a voltage vector between the grid and a connected power converter. The QTF and PLL methods are suitable for either single-phase applications or n-phase (any number of phases) applications. A frequency estimator estimates the grid frequency of the electric grid and outputs the estimated frequency to the QTF algorithms. The frequency estimator may include a three-phase phase-locked-loop (three-phase PLL) suitable for estimating the center frequencies of multiple phases of the electric grid. The frequency estimator may also include means for reducing the harmonics in the grid system.

Abstract: A system and method for controlling an electrical device is provided. The method comprises receiving three phase power from a source, decomposing signals representative of power in each phase of the three phase power to provide a positive-sequence component of each phase and tracking the positive-sequence component of each phase via a phase locked loop and a tracking filter.

Abstract: A phase angle detector with a PLL, a power converter, and a method for reducing offsets in an input signal, in which an adaptive offset processor selectively removes a DC offset component from the input signal to generate a modified signal including a fundamental frequency component and higher order harmonics of the input signal with the DC offset component removed, and the PLL provides a phase angle signal at least partially according to the modified signal.

Abstract: A system and method for controlling an electrical device is provided. The method includes receiving three phase power from a source, decomposing signals representative of power in each phase of the three phase power to provide a positive-sequence component of each phase and tracking the positive-sequence component of each phase via a phase locked loop and a tracking filter.

Abstract: Power conversion systems and methods are presented for detecting input filter capacitor degradation or approach of end of operational life based on filter capacitor current measurements using single and/or dual threshold comparisons for computed instantaneous sum of squares of filter currents or power values.

Abstract: The present techniques include methods and systems for operating an inverter to maintain a lifespan of the inverter. In some embodiments, the switching frequency and/or the output current of the inverter may be changed such that stress may be reduced on the inverter bond wires of the inverter. More specifically, embodiments involve calculating the aging parameters for certain operating conditions of the inverter and determining whether the operating conditions result in aging the inverter to a point which reduces the inverter lifespan below a desired lifespan. If the operating conditions reduce the inverter lifespan below the desired lifespan, the switching frequency may be reduced to a lower or minimum switching frequency of the inverter and/or the output current of the inverter may be reduced to a maximum output current at the minimum switching frequency.

Abstract: Control systems, methods and power conversion systems are presented for reducing common mode voltages in AC motor loads driven by inverter PWM control using switching sequences with only active vectors where a first vector of each switching sequence differs by one phase switching state from a last vector of a switching sequence of an adjacent sector, along with enhanced deadtime compensation and reflected wave reduction techniques in providing pulse width modulated switching signals to a switching inverter.

Abstract: The present techniques include methods and systems for operating an inverter to maintain a lifespan of the inverter. In some embodiments, the switching frequency and/or the output current of the inverter may be changed such that stress may be reduced on the inverter bond wires of the inverter. More specifically, embodiments involve calculating the aging parameters for certain operating conditions of the inverter and determining whether the operating conditions result in aging the inverter to a point which reduces the inverter lifespan below a desired lifespan. If the operating conditions reduce the inverter lifespan below the desired lifespan, the switching frequency may be reduced to a lower or minimum switching frequency of the inverter and/or the output current of the inverter may be reduced to a maximum output current at the minimum switching frequency.

Abstract: Methods and systems for synchronizing an electric grid having unbalanced voltages are provided. A voltage vector may be filtered in a quadrature tracking filter (QTF) to generate a quadrature signal. A phase-locked-loop (PLL) operation may be performed on the quadrature signal to monitor a voltage vector between the grid and a connected power converter. The QTF and PLL methods are suitable for either single-phase applications or n-phase (any number of phases) applications. A frequency estimator estimates the grid frequency of the electric grid and outputs the estimated frequency to the QTF algorithms. The frequency estimator may include a three-phase phase-locked-loop (three-phase PLL) suitable for estimating the center frequencies of multiple phases of the electric grid. The frequency estimator may also include means for reducing the harmonics in the grid system.

Abstract: Methods and systems for synchronizing an electric grid having unbalanced voltages are provided. A voltage vector may be filtered in a quadrature tracking filter (QTF) to generate a quadrature signal. The inputs to the QTF may be either single input, multiple outputs, or alternatively, multiple inputs, multiple outputs. Furthermore, the second state of either of the two QTF transformations may be either positive or negative. A phase-locked-loop (PLL) operation may be performed on the quadrature signal to monitor a voltage vector between the grid and a connected power converter. The QTF and PLL methods are suitable for either single-phase applications or n-phase (any number of phases) applications.

Abstract: The present techniques include methods and systems for operating a wind power system to maintain a lifespan of the rotor side converter. In some embodiments, the current of the rotor side converter may be minimized to reduce the stress and/or junction temperature variation in the switching transistors and bond wires of the converter. More specifically, embodiments involve using a minimal current in the rotor side converter based on the rotor side and grid side reactive powers. If the grid side reactive power is greater than a maximum grid side reactive power, the grid side reactive power may be reduced. Further, if the total reactive power does not meet the grid reactive power requirements, the minimal current in the rotor side converter may be adjusted such that the system may sufficiently power the grid.

Abstract: Methods and systems for tracking an electronic signal corresponding to an operating frequency of an electronic component are provided. A method may include sampling the signal to determine previous and current time samples of the signal. A frequency of interest in the signal may also be pre-warped to decrease adverse warping effects resulting from processing signals having relatively higher operating frequencies. The previous and current time samples of the signals, along with the pre-warped frequency of interest, may be input into a digital tracking filter. The digital tracking filter may be configured to execute one or more algorithms on the previous and current time samples and the pre-warped frequency of interest to estimate a current operating frequency.