Fractional order power point tracking

• US 9,523,723 B2
• Filed: 04/09/2013
• Issued: 12/20/2016
• Est. Priority Date: 04/09/2012
• Status: Active Grant

• Current Assignee: Utah State University
• Original Assignee: Utah State University
• Inventors: Malek, Hadi, Chen, YangQuan
• Primary Examiner(s): Raymond, Edward
• Application Number:
  US13/859,394
• Publication Number:
  US 20130268219A1
• Time in Patent Office: 1,351 Days
• Field of Search: 702/60, 702/64, 702182-185
• US Class Current: 1/1
• CPC Class Codes: G01R 21/06 by measuring current and voltage G01R21/08 - G01R21/133 take precedence
• CPC Class Codes: G05F 1/67 to the maximum power available from a generator, e.g. from solar cell

Abstract

For maximum power point tracking, a method filters a power monitoring signal with a tracking fractional order filter to generate a filtered power monitoring signal. The method further generates a tracking signal tracking the power point from the filtered power monitoring signal.

Claims

1. A method for power point tracking comprising:

receiving raw power from a power generator;

determining with a fractional order apparatus stable coefficients and fractional orders for a tracking fractional order filter and an integrator fractional order filter;

filtering through a demodulation module a power monitoring signal with the tracking fractional order filter and generating a filtered power monitoring signal;

demodulating the filtered power monitoring signal with a perturbation signal;

generating a tracking signal tracking the power point from the filtered power monitoring signal;

integrating through an integration module the tracking signal with the integrator fractional order filter to form a feedback signal and summing the feedback signal with the perturbation signal to generate a control signal; and

converting the raw power to output power through a power converter.

2. The method of claim 1, further comprising determining the tracking fractional order filter by

substituting a fractional order for the integer order.

3. The method of claim 1, wherein the power monitoring signal comprises a current and a voltage, the filtered power monitoring signal is calculated as dI/dV, and the power point is at dP/dV=0, where I is current, V is voltage, and P is Power.

4. The method of claim 1, wherein the tracking fractional order filter is a high pass Bode Ideal Cutoff (BICO) filter and the response of the high pass BICO filter H(s) is calculated as

5. The method of claim 4, wherein the response of the high pass BICO filter H(z) is calculated as

6. The method of claim 1, further comprising filtering the tracking signal with a low pass fractional order filter.

7. An apparatus for power point tracking comprising:

a tracking fractional order filter filtering a power monitoring signal to generate a filtered power monitoring signal;

a coefficients module calculating stable coefficients for an integer order filter;

a fractional order module substituting a fractional order for the integer order to determine the tracking fractional order filter; and

a demodulator demodulating the filtered power monitoring signal with a perturbation signal to generate a tracking signal tracking the power point.

8. The apparatus of claim 7, wherein the power monitoring signal comprises a current and a voltage, the filtered power monitoring signal is calculated as dI/dV, and the power point is at dP/dV=0, where I is current, V is voltage, and P is Power.

9. The apparatus of claim 7, wherein the tracking fractional order filter is a high pass Bode Ideal Cutoff (BICO) filter.

10. The apparatus of claim 9, wherein the response of the high pass BICO filter H(s) is calculated as

11. The apparatus of claim 10, wherein the response of the high pass BICO filter H(z) is calculated as

12. The apparatus of claim 7, further comprising a low pass fractional order filter filtering the tracking signal.

13. The apparatus of claim 12, wherein the low pass fractional order filter is a low pass BICO filter.

14. The apparatus of claim 7, further comprising an integrator fractional order filter integrating the tracking signal to form a feedback signal and summing the feedback signal with the perturbation signal to generate a control signal.

15. A system for power point tracking comprising:

a power generator generating raw power;

a power converter converting the raw power to output power;

a fractional order apparatus determining stable coefficients and fractional orders for a tracking fractional order and an integrator fractional order filter;

a demodulation module filtering a power monitoring signal with the tracking fractional order filter to generate a filtered power monitoring signal and demodulating the filtered power monitoring signal with a perturbation signal to generate a tracking signal tracking the power point; and

an integration module integrating the tracking signal with the integrator fractional order filter to form a feedback signal and summing the feedback signal with the perturbation signal to generate a control signal.

16. The system of claim 15, wherein the power monitoring signal measures the raw power.

17. The system of claim 15, wherein the power monitoring signal measures the output power.

18. The system of claim 15, the tracking fractional order filter is a high pass Bode Ideal Cutoff (BICO) filter.