Power conditioning units
First Claim
1. A method of maximum power point tracking (MPPT) in a power conditioning unit for delivering power from a DC power source to an AC circuit output, the power conditioning unit including an energy storage capacitor for storing energy from the DC power source and a DC to AC converter delivering AC power to the AC circuit output, the method comprising:
- tracking a maximum power point (MPP) of the DC power source by controlling the DC to AC converter to convert energy stored in the energy storage capacitor to AC power for the AC circuit output, wherein tracking an MPP comprises;
sensing, at a circuit node coupled to the energy storage capacitor, a signal responsive to a level of power drawn from the DC power source;
determining whether the level of power is increasing or decreasing relative to a previously sensed level of power; and
controlling a frequency of the DC to AC converter to maintain operation of the power conditioning unit at the MPP based at least in part on whether the level of power is increasing or decreasing.
1 Assignment
0 Petitions
Accused Products
Abstract
We describe a power conditioning unit with maximum power point tracking (MPPT) for a dc power source, in particular a photovoltaic panel. A power injection control block has a sense input coupled to an energy storage capacitor on a dc link and controls a dc-to-ac converter to control the injected mains power. The power injection control block tracks the maximum power point by measuring a signal on the dc link which depends on the power drawn from the dc power source, and thus there is no need to measure the dc voltage and current from the dc source. In embodiments the signal is a ripple voltage level and the power injection control block controls an amplitude of an ac current output such that an amount of power transferred to the grid mains is dependent on an amplitude of a sinusoidal voltage component on the energy storage capacitor.
-
Citations
20 Claims
-
1. A method of maximum power point tracking (MPPT) in a power conditioning unit for delivering power from a DC power source to an AC circuit output, the power conditioning unit including an energy storage capacitor for storing energy from the DC power source and a DC to AC converter delivering AC power to the AC circuit output, the method comprising:
tracking a maximum power point (MPP) of the DC power source by controlling the DC to AC converter to convert energy stored in the energy storage capacitor to AC power for the AC circuit output, wherein tracking an MPP comprises; sensing, at a circuit node coupled to the energy storage capacitor, a signal responsive to a level of power drawn from the DC power source; determining whether the level of power is increasing or decreasing relative to a previously sensed level of power; and controlling a frequency of the DC to AC converter to maintain operation of the power conditioning unit at the MPP based at least in part on whether the level of power is increasing or decreasing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
10. A method of maximum power point tracking (MPPT) in a power conditioning unit for delivering power from a DC power source to an AC mains, the power conditioning unit including an energy storage capacitor for storing energy from the DC power source and for delivering energy to the AC mains, the method comprising:
tracking a maximum power point (MPP) of the DC power source by controlling a DC to AC converter converting energy stored in the energy storage capacitor to AC power for the AC mains, wherein tracking the MPP comprises; sensing, at a circuit node coupled to the energy storage capacitor, a signal responsive to a level of power drawn from the DC power source; and controlling the DC to AC converter to adjust an amplitude of an AC output of the power conditioning unit to substantially maximize the sensed signal. - View Dependent Claims (11, 12, 13, 14, 15)
-
16. A method of maximum power point tracking in a power conditioning unit for delivering power from a DC power source to an AC mains, the power conditioning unit including an energy storage capacitor for storing energy from the DC power source and for delivering energy to the AC mains, wherein in operation a voltage on the energy storage capacitor has a sinusoidal voltage component at twice a frequency of the AC mains, the method comprising:
-
controlling an amplitude of an AC current provided to the AC mains such that an amount of power transferred to the AC mains is dependent on an amplitude of the sinusoidal voltage component on the energy storage capacitor, wherein the controlling is performed by controlling a DC to AC converter converting energy stored in the energy storage capacitor to AC power for the AC mains; and tracking a maximum power point of the DC power source by controlling the DC to AC converter. - View Dependent Claims (17, 18, 19, 20)
-
Specification