Harmonic regulator for current source rectification and inversion
A methods and systems for generating rectified signals are disclosed. For example, a system performing the methods includes a current source rectifier which has a plurality of switches configured to receive an input current from an AC voltage source and to receive a plurality of control signals. The switches are configured to produce a rectified output current based on the input current and the control signals. The system also includes a rectifier controller configured to receive a current sense signal indicative of the rectified output current and to generate the control signals based at least in part on the current sense signal, where the control signals cause the current source rectifier to attenuate at least one of a plurality of harmonic frequencies in the rectified output current.
1. A system, comprising:
a rectifier circuit comprising a plurality of switches configured to receive an alternating current (AC) input signal from an AC source and to receive a plurality of control signals, wherein the control signals cause the switches to generate a rectified output signal based on the input signal and the control signals, and wherein; and
a rectifier controller configured to generate one or more harmonic frequency signals based on the AC input signal, wherein each of the harmonic frequency signals has a frequency corresponding with a harmonic frequency of the AC input signal, and to generate the control signals based in part on the harmonic frequency signals, wherein, at least partly because of the harmonic frequency signals, the control signals additionally cause the switches to attenuate one or more harmonic frequencies of the AC input signal in the rectified output signal.
2. The system of claim 1 , wherein the AC source is a three-phase AC voltage source.
3. The system of claim 1 , wherein the plurality of switches are metal-oxide field effect transistors (MOSFETs).
4. The system of claim 1 , wherein the rectifier controller further comprises:
a DC offset circuit configured to remove a DC component from a sensing signal to generate an AC sense signal, wherein the sensing signal is indicative of the rectified output signal,
one or more harmonic regulator circuits, each configured to receive the AC sense signal and a particular harmonic frequency signal, to generate a particular harmonic compensation signal based on the particular harmonic frequency signal and the AC sense signal, and to generate the control signals based at least in part on the particular harmonic compensation signal.
5. The system of claim 4 , wherein the one or more harmonic regulator circuits comprises:
a second harmonic regulator circuit configured to receive the AC sense signal and a second harmonic frequency signal, and to generate a second harmonic compensation signal based on the second harmonic frequency signal and the AC sense signal;
a third harmonic regulator circuit configured to receive the AC sense signal and a third harmonic frequency signal, and to generate a third harmonic compensation signal based on the third harmonic frequency signal and the AC sense signal; and
a sixth harmonic regulator circuit configured to receive the AC sense signal and a sixth harmonic frequency signal, and to generate a sixth harmonic compensation signal based on the sixth harmonic frequency signal and the AC sense signal.
6. The system of claim 1 , wherein the rectifier controller is further configured to generate a controlled output voltage, and to receive a reference voltage, and wherein the rectifier controller is further configured to generate the control signals based at least in part on the reference voltage, wherein the control signals cause the rectifier controller to generate the rectified output signal such that the controlled output voltage is substantially equal to the reference voltage.
7. The system of claim 6 , wherein the rectifier controller comprises:
a voltage regulator circuit configured to generate a difference signal based on a difference between the reference voltage and the controlled output voltage,
wherein the rectifier controller is further configured to generate the control signals based on the difference signal.
8. The system of claim 7 , wherein the rectifier controller further comprises:
a DC offset circuit configured to remove a DC component from a sensing signal to generate an AC sense signal, wherein the sensing signal is indicative of the rectified output signal,
one or more harmonic regulator circuits, each configured to receive the AC sense signal and a particular harmonic frequency signal, to generate a particular harmonic compensation signal based on the particular harmonic frequency signal and the AC sense signal, and to generate the control signals based at least in part on the particular harmonic compensation signal.
9. The system of claim 6 , further comprising an inverter configured to receive the controlled output voltage and to generate an AC voltage output based on the controlled output voltage.
10. The system of claim 9 , wherein the inverter is a current source inverter.
11. The system of claim 9 , wherein the inverter is a voltage source inverter.
12. A variable speed drive, comprising:
a rectifier circuit comprising a plurality of switches configured to receive an alternating current (AC) input signal from an AC source and to receive a plurality of control signals, wherein the control signals cause the switches to generate a rectified output signal based on the input signal and the control signals, and wherein; and
a rectifier controller configured to generate one or more harmonic frequency signals based on the AC input signal, wherein each of the harmonic frequency signals has a frequency corresponding with a harmonic frequency of the AC input signal, and to generate the control signals based in part on the harmonic frequency signals, wherein, at least partly because of the harmonic frequency signals, the control signals additionally cause the switches to attenuate one or more harmonic frequencies of the AC input signal in the rectified output signal; and
an inverter configured to receive the rectified output signal and to generate an AC voltage output based on the rectified output signal.
13. The variable speed drive of claim 12 , wherein the AC source is a three-phase AC voltage source.
14. The variable speed drive of claim 12 , wherein the plurality of switches are metal-oxide field effect transistors (MOSFETs).
15. The variable speed drive of claim 12 , further comprising:
a DC offset circuit configured to remove a DC component from a sensing signal to generate an AC sense signal, wherein the sensing signal is indicative of the rectified output signal,
one or more harmonic regulator circuits, each configured to receive the AC sense signal and a particular harmonic frequency signal, to generate a particular harmonic compensation signal based on the particular harmonic frequency signal and the AC sense signal, and to generate the control signals based at least in part on the particular harmonic compensation signal.
16. The variable speed drive of claim 15 , wherein the one or more harmonic regulator circuits comprises:
a second harmonic regulator circuit configured to receive the AC sense signal and a second harmonic frequency signal, and to generate a second harmonic compensation signal based on the second harmonic frequency signal and the AC sense signal;
a third harmonic regulator circuit configured to receive the AC sense signal and a third harmonic frequency signal, and to generate a third harmonic compensation signal based on the third harmonic frequency signal and the AC sense signal; and
a sixth harmonic regulator circuit configured to receive the AC sense signal and a sixth harmonic frequency signal, and to generate a sixth harmonic compensation signal based on the sixth harmonic frequency signal and the AC sense signal.
17. The variable speed drive of claim 12 , wherein the rectifier controller is further configured to generate a controlled output voltage, and to receive a reference voltage, and wherein the rectifier controller is further configured to generate the control signals based at least in part on the reference voltage, wherein the control signals cause the rectifier controller to generate the rectified output signal such that the controlled output voltage is substantially equal to the reference voltage.
18. The variable speed drive of claim 17 , wherein the rectifier controller comprises:
a voltage regulator circuit configured to generate a difference signal based on a difference between the reference voltage and the controlled output voltage; and
a power switch state selection circuit configured to generate the control signals based on the difference signal.
19. The variable speed drive of claim 18 , wherein the rectifier controller further comprises:
a DC offset circuit configured to remove a DC component from a sensing signal to generate an AC sense signal, wherein the sensing signal is indicative of the rectified output signal,
one or more harmonic regulator circuits, each configured to receive the AC sense signal and a particular harmonic frequency signal, to generate a particular harmonic compensation signal based on the particular harmonic frequency signal and the AC sense signal, and to generate the control signals based at least in part on the particular harmonic compensation signal.
20. The variable speed drive of claim 19 , wherein the inverter is a current source inverter.
21. The variable speed drive of claim 19 , wherein the inverter is a voltage source inverter.