Photovoltaic DC-to-AC power converter and control method
First Claim
1. An apparatus and electrical power converter topology for converting the DC energy from a solar photovoltaic source to AC energy, where said AC energy is fed into a single phase, split-phase or poly-phase AC electric utility grid, other AC voltage source or other AC voltage sink, hereafter collectively referred to as the AC load, and comprising;
- a control circuit to provide regulation and protection;
a pulse width modulated boost circuit to raise a mono-polar DC voltage or bi-polar DC voltages of said photovoltaic source; and
a capacitive energy storage element to store the output energy of a boost circuit at said raised voltage or voltages and a pulse width modulated buck circuit to convert the energy in said capacitive energy storage element into sinewaves of current synchronized with an AC load frequency to substantially achieve unity power factor at said AC load and where said control circuit is further described as having two servo control loops, one loop that regulates the voltage or voltages of said photovoltaic source by perturbing or incrementally changing the pulse width of said boost circuit and observing the resulting change in the power delivered from said photovoltaic source to said capacitive energy storage element and where this perturb and observe algorithm dynamically seeks the photovoltaic source voltage or voltages that will maximize the power out of said photovoltaic source and a second loop that regulates the voltage or voltages of said energy storage element by controlling the pulse width modulation of said pulse width modulated buck circuit to adjust the amplitude of said sinewaves of current sourced into said AC load.
4 Assignments
0 Petitions
Accused Products
Abstract
An apparatus and method of control for converting DC (direct current) power from a solar photovoltaic source to AC (alternating current) power. A novel DC-to-AC power converter topology and a novel control method are disclosed. This combination of topology and control are very well suited for photovoltaic microinverter applications. Also, a novel variant of this control method is illustrated with a number of known photovoltaic DC-to-AC power converter topologies. The primary function of both control methods is to seek the maximum power point (MPP) of the photovoltaic source with novel, iterative, perturb and observe control algorithms. The control portion of this invention discloses two related control methods, both an improvement over prior art by having greatly improved stability, dynamic response and accuracy.
208 Citations
8 Claims
-
1. An apparatus and electrical power converter topology for converting the DC energy from a solar photovoltaic source to AC energy, where said AC energy is fed into a single phase, split-phase or poly-phase AC electric utility grid, other AC voltage source or other AC voltage sink, hereafter collectively referred to as the AC load, and comprising;
-
a control circuit to provide regulation and protection; a pulse width modulated boost circuit to raise a mono-polar DC voltage or bi-polar DC voltages of said photovoltaic source; and a capacitive energy storage element to store the output energy of a boost circuit at said raised voltage or voltages and a pulse width modulated buck circuit to convert the energy in said capacitive energy storage element into sinewaves of current synchronized with an AC load frequency to substantially achieve unity power factor at said AC load and where said control circuit is further described as having two servo control loops, one loop that regulates the voltage or voltages of said photovoltaic source by perturbing or incrementally changing the pulse width of said boost circuit and observing the resulting change in the power delivered from said photovoltaic source to said capacitive energy storage element and where this perturb and observe algorithm dynamically seeks the photovoltaic source voltage or voltages that will maximize the power out of said photovoltaic source and a second loop that regulates the voltage or voltages of said energy storage element by controlling the pulse width modulation of said pulse width modulated buck circuit to adjust the amplitude of said sinewaves of current sourced into said AC load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
Specification