Intra-module DC-DC converter and a PV-module comprising same

• US 10,135,252 B2
• Filed: 09/24/2014
• Issued: 11/20/2018
• Est. Priority Date: 09/24/2013
• Status: Active Grant

• Current Assignee: Katholieke Universiteit Leuven
• Original Assignee: Katholieke Universiteit Leuven
• Inventors: Chatterjee, Urmimala, Driesen, Johan
• Primary Examiner(s): Chang, Joseph
• Application Number:
  US15/024,456
• Publication Number:
  US 20160268806A1
• Time in Patent Office: 1,518 Days
• Field of Search: 307 82
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02M 3/04 by static converters
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02M 3/1586 switched with a phase shift, i.e. interleaved
• CPC Class Codes: H02M 7/44 by static converters
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

The present invention relates to an intra-module DC-DC power converter and a Photovoltaic (PV) module comprising same. The switching frequency of said intra-module DC-DC power converters may be 500 kHz. The PV module may have a controller and a plurality of switches for allowing each individual string of said PV module to be connected to one corresponding DC-DC converter, or for allowing two or more strings of said module to be connected in series and to apply the voltage of the combined string to a single DC-DC converter. The input voltage range of the DC-DC converters may be 10V to 30V, and the output voltage range may be 120V. The DC-DC converters may be connected in series or in parallel. Multiple such PV panels may be connected in a DC-grid.

Claims

1. A photovoltaic module comprising:

at least two strings, each string including a plurality of solar cells connected in series;

a circuit for obtaining power from a photovoltaic unit, the circuit comprising at least two intra-module DC-DC power converters connected with a string and in parallel between each other;

wherein said intra-module DC-DC power converters comprise;

at least one multiplier stage (M), said multiplier stage comprising two capacitors (C_M1, C_M2), each capacitor respectively connected to a diode (D_M1, D_M2), and wherein said diodes (D_M1, D_M2) of the at least one multiplier cell are adapted to charge the multiplier capacitors (C_M1, C_M2) with a charge voltage (V_M), and

wherein an input signal (V_in) from the photovoltaic unit is converted into an output signal (V_out), wherein said output signal is (M+1) times the charge voltage (V_M).

2. The photovoltaic module of claim 1, wherein the two capacitors (C_M1, C_M2), are respectively connected in series by one diode (D_M1, D_M2) and both the capacitors and diodes are connected in parallel with an output capacitor (C₀).

3. The photovoltaic module of claim 1, wherein each capacitor (C_M1, C_M2) is connected in series to at least one switch, resulting in two switches (S₁, S₂) and wherein said switches are connected in parallel.

4. The photovoltaic module of claim 3, wherein the switching frequency of said switches is 400 to 500 kHz or the switching frequency is fixed.

5. The photovoltaic module of claim 1, wherein the circuit further comprises two inductors (L₁, L₂).

6. The photovoltaic module of claim 1, wherein the intra-module DC-DC power converter is a non-isolated power converter or wherein the intra-module DC-DC power converter is a boost power converter.

7. The photovoltaic module of claim 1, wherein the input signal of the intra-module DC-DC power converter is an input voltage (V_in) that ranges from at least 10 to 30V or wherein the input signal of the intra-module DC-DC power converter is an input current of at most 8 A.

8. The photovoltaic module of claim 1, wherein the output signal of the intra-module DC-DC power converter is a voltage (V_out) of at least 120V.

9. The photovoltaic module of claim 1, wherein the maximal voltage gain of the intra-module DC-DC power converter, of a circuit comprising two multiplier stages (M=2), is 12.

10. The photovoltaic module according to claim 1, wherein the switching frequency lies in the range of 400 to 500 kHz, and the output voltage lies in the range of 120 to 360 V;

wherein the circuit comprises an intra-module DC-DC power converter, wherein said intra-module DC-DC power converter comprises;

at least one multiplier stage (M), said multiplier stage comprising two capacitors (C_M1, C_M2), each capacitor respectively connected to a diode (D_M1, D_M2), and wherein said diodes (D_M1, D_M2) of the at least one multiplier cell are adapted to charge the multiplier capacitors (C_M1, C_M2) with a charge voltage (V_M);

wherein an input signal (V_in) from the photovoltaic unit is converted into an output signal (V_out), wherein said output signal is (M+1) times the charge voltage (V_M);

wherein the module comprises a first circuit comprising a first intra-module DC-DC power converter coupled or connected to a first photovoltaic unit, the first circuit comprises an intra-module DC-DC power converter, wherein said intra-module DC-DC power converter comprises;

at least one multiplier stage (M), said multiplier stage comprising two capacitors (C_M1, C_M2), each capacitor respectively connected to a diode (D_M1, D_M2), and wherein said diodes (D_M1, D_M2) of the at least one multiplier cell are adapted to charge the multiplier capacitors (C_M1, C_M2) with a charge voltage (V_M), and wherein an input signal (V_in) from the photovoltaic unit is converted into an output signal (V_out), wherein said output signal is (M+1) times the charge voltage (V_M);

a second circuit comprising a second intra-module DC-DC power converter coupled or connected in series or parallel with the first intra-module DC-DC power converter and coupled or connected to a second photovoltaic unit;

a controller that is adapted to control a voltage of the first and second intra-module DC-DC power converters.

11. The photovoltaic module according to claim 1, further comprising a plurality of strings, each string being connectable to at least one corresponding DC-DC power converter, wherein the DC-DC power converters of all the strings are connected in parallel, and are adapted for generating a same output voltage (Vout) or wherein the DC-DC power converters of all the strings are connected in series.

12. The photovoltaic module according to claim 1, further comprising a plurality of switches for allowing the strings to be connected in series, and to allow the series connection to be connected to one of said DC-DC power converters.

13. A DC power grid comprising at least two photovoltaic modules according to claim 1.

14. Use of a photovoltaic module according to claim 1 for obtaining power from a photovoltaic unit or to enable a distributed power management system.

15. A system for controlling a plurality of photovoltaic units, the system comprising:

a first photovoltaic module comprising;

at least two strings, each string including a plurality of solar cells connected in series,

a first circuit comprising a first intra-module DC-DC power converter coupled or connected to a first photovoltaic unit, the first circuit comprises at least two intra-module DC-DC power converters connected with a string and in parallel between each other, wherein said intra-module DC-DC power converters comprise;

at least one multiplier stage (M), said multiplier stage comprising two capacitors (C_M1, C_M2), each capacitor respectively connected to a diode (D_M1, D_M2), and wherein said diodes (D_M1, D_M2) of the at least one multiplier cell are adapted to charge the multiplier capacitors (C_M1, C_M2) with a charge voltage (V_M), and wherein an input signal (V_in) from the photovoltaic unit is converted into an output signal (V_out), wherein said output signal is (M+1) times the charge voltage (V_M);

a second photovoltaic module comprising;

at least two strings, each string including a plurality of solar cells connected in series,

a second circuit comprising a second intra-module DC-DC power converter coupled or connected in series or parallel with the first intra-module DC-DC power converter and coupled or connected to a second photovoltaic unit;

a controller that is adapted to control a voltage of the first and second intra-module DC-DC power converters.

16. The system according to claim 15, further comprising at least a third intra-module DC-DC power converter, wherein said at least third intra-module DC-DC power converter is coupled or connected in series or parallel to said first and/or second DC-DC power converter.

17. The system of claim 15, further comprising converting means to connect or couple an output of said DC-DC power converters to a public grid through a next stage of power conversion.