Apparatus and method for controlling DC-AC power conversion
First Claim
1. An apparatus for controlling the delivery of power from a photovoltaic (“
- PV”
) cell to an alternating-current (AC) grid at a grid voltage and grid frequency, the apparatus comprising;
an inverter comprising;
an input converter configured to deliver power from the PV cell to a galvanically isolated unipolar bus, the input converter comprising a maximum-power-point-tracking (“
MPPT”
) device configured to determine the maximum amount of power that may be withdrawn from the photovoltaic cell and deliver a setpoint value, iSIC, for the current that is drawn by the input converter from the PV cell, wherein the input converter is further to receive a measurement of the voltage of the PV cell, VI, and to calculate and deliver a power delivery setpoint Ps=VI·
iSIC;
an active filter configured to supply energy to and absorb energy from the unipolar bus; and
an output converter configured to deliver power from the unipolar bus to the AC grid, andan inverter controller configured to maintain a voltage of the unipolar bus at a pre-determined value, the inverter controller comprising;
an input converter controller to control a current delivered by the input converter to the unipolar bus;
an output converter controller to control the output converter to deliver power to the AC grid; and
an active filter controller to control the active filter to supply time-varying power to the output converter.
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Accused Products
Abstract
An apparatus and method for controlling the delivery of power from a DC source to an AC grid includes an inverter configured to deliver power from the unipolar input source to the AC grid and an inverter controller. The inverter includes an input converter, an active filter, and an output converter. The inverter controller includes an input converter controller, an active filter controller and an output converter controller. The input converter controller is configured to control a current delivered by the input converter to a galvanically isolated unipolar bus of the inverter. The output converter is configured to control the output converter to deliver power to the AC grid. Additionally, the active filter controller is configured to control the active filter to supply substantially all the power that is deliver by the output controller to the AC grid at a grid frequency.
46 Citations
51 Claims
-
1. An apparatus for controlling the delivery of power from a photovoltaic (“
- PV”
) cell to an alternating-current (AC) grid at a grid voltage and grid frequency, the apparatus comprising;an inverter comprising; an input converter configured to deliver power from the PV cell to a galvanically isolated unipolar bus, the input converter comprising a maximum-power-point-tracking (“
MPPT”
) device configured to determine the maximum amount of power that may be withdrawn from the photovoltaic cell and deliver a setpoint value, iSIC, for the current that is drawn by the input converter from the PV cell, wherein the input converter is further to receive a measurement of the voltage of the PV cell, VI, and to calculate and deliver a power delivery setpoint Ps=VI·
iSIC;an active filter configured to supply energy to and absorb energy from the unipolar bus; and an output converter configured to deliver power from the unipolar bus to the AC grid, and an inverter controller configured to maintain a voltage of the unipolar bus at a pre-determined value, the inverter controller comprising; an input converter controller to control a current delivered by the input converter to the unipolar bus; an output converter controller to control the output converter to deliver power to the AC grid; and an active filter controller to control the active filter to supply time-varying power to the output converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
- PV”
-
39. A method for controlling an inverter that is configured to deliver power from a unipolar input source to an alternating-current (“
- AC”
) grid at a grid voltage and grid phase, comprising;delivering a pre-determined amount of power from the unipolar input source to a unipolar bus that is galvanically isolated from the unipolar input source using an input converter; supplying energy to and absorbing energy from the unipolar bus using an active filter comprising an active filter capacitor; delivering power from the unipolar bus to the AC grid using an output converter; controlling the operation of the inverter using an inverter controller, wherein controlling the operation of the inverter comprises (i) controlling the operation of the input converter to deliver substantially all the average power delivered to the AC grid, (ii) controlling the active filter to deliver substantially all the time-varying power that is delivered to the AC grid, and (iii) regulating the unipolar bus voltage to a first pre-determined value; and providing to the output converter controller; a value indicative of the pre-determined amount of power, Ps;
.a measurement of the rms grid voltage, VL; a measurement of the grid phase, θ
,a pre-determined setpoint value of a power factor angle, φ
, and,wherein controlling the output converter comprises controlling the current delivered by the output converter to the AC grid to comprise a time-varying component essentially equal to;
iLFF(t)=(sqrt(2)·
Ps/VL)·
(cos(θ
+φ
)/cos(φ
). - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
- AC”
Specification