Power system having a phase locked loop with a notch filter
First Claim
1. A power system associated with a three phase line comprising:
- a three phase to two phase transformation processor responsive to the three phase line for generating two phase x and y axis sequence components;
a stationary to rotating reference frame converter responsive to the x and y axis sequence components and to an angle signal for generating rotating D and Q axis sequence components wherein the D and Q axis sequence components have a phase determined by the angle signal; and
a phase locked loop (PLL) responsive to a selected one of the rotating D and Q axis sequence components for generating the angle signal, wherein the PLL comprises a notch filter.
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Accused Products
Abstract
A power system having a phase locked loop (PLL) with a notch filter for synchronous reference frame sequence separation. The notch filter includes a generalized integrator tuned to the notch frequency. The output of the generalized integrator is summed with the filter input signal and the output of the summer is fed back to the integrator input. In one embodiment, the notch filter is programmable by a control signal generated in response to the filter output signal, thereby causing the filter to self-regulate to a frequency related to the PLL input signal. Illustrative power systems include active VAR generators and active rectifiers. One or more additional notch filters may be used to remove harmonic components from derived synchronous reference frame sequence components.
38 Citations
20 Claims
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1. A power system associated with a three phase line comprising:
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a three phase to two phase transformation processor responsive to the three phase line for generating two phase x and y axis sequence components; a stationary to rotating reference frame converter responsive to the x and y axis sequence components and to an angle signal for generating rotating D and Q axis sequence components wherein the D and Q axis sequence components have a phase determined by the angle signal; and a phase locked loop (PLL) responsive to a selected one of the rotating D and Q axis sequence components for generating the angle signal, wherein the PLL comprises a notch filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A notch filter comprising:
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a summer circuit having a first input port to which a filter input signal is coupled, a second input port, and an output port at which a filtered signal is provided; and a generalized integrator having a first input port coupled to the output port of the summer circuit, a second input port responsive to a control signal, and an output port at which an error signal is provided, wherein the output port of the generalized integrator is coupled to the second input port of the summer circuit and wherein the generalized integrator is tuned to the frequency of the control signal. - View Dependent Claims (13, 14, 15, 16)
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17. A phase locked loop (PLL) for generating an angle signal for use in converting a stationary reference frame signal to a synchronous reference frame signal comprising:
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regulator having an input port to which an input signal to the PLL is coupled and an output port; a filter having an input port coupled to the output port of the regulator and an output port, said filter comprising; a summer circuit having a first input port coupled to the output port of the PI regulator, a second input port, and an output port at which a filtered signal is provided; and a generalized integrator having a first input port coupled to the output port of the summer circuit, a second input port responsive to a control signal, and an output port at which an error signal is provided, wherein the output port of the generalized integrator is coupled to the second input port of the summer circuit and wherein the generalized integrator is tuned to the frequency of the control signal; and an integrator having an input port coupled to the output port of the filter and an output port at which the angle signal is provided.
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18. A phase locked loop (PLL) for generating an angle signal for use in converting a stationary reference frame signal to a synchronous reference frame signal comprising:
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a regulator responsive to an input signal for regulating the input signal to zero volts; a notch filter having an input port coupled to an output port of said regulator and an output port at which a filtered signal is provided, said notch filter being tuned in response to a control signal; and a circuit coupled to the output port of said notch filter and responsive to the filtered signal for generating said control signal, wherein the control signal has a level related to the frequency of the regulator input signal. - View Dependent Claims (19, 20)
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Specification