Renewable energy power generation systems
First Claim
1. A modular adjustable power factor renewable energy inverter system, the system comprising:
- a plurality of inverter modules, each inverter module having a dc power input and an ac power output;
a common grid power feed coupled to each said inverter module ac power output; and
a system controller having a communications link to each said inverter module to receive power data from the inverter module and to send control data to the inverter module,wherein each said inverter module further comprises;
a series combination of a capacitor and a controllable switching device connected in parallel across said ac power output of the inverter module;
a communication interface for communicating with said system controller;
a power measurement system coupled to said communication interface to measure one or more parameters relating to a net level of ac power provided by the inverter module to said common grid power feed, and to provide power data to said communication interface for transmission to said system controller, wherein the power data defines said net level of ac power provided; and
a power factor controller, coupled to said communication interface to receive control data from said system controller, and coupled to said controllable switching device to control said controllable switching device in response to said received control data to switch said capacitor into/out of parallel connection across said ac power output of said inverter module,wherein said system controller is configured to;
receive said power data from each said inverter module;
sum the net level of ac power from each said inverter module to determine a total net level of ac power provided by said plurality of inverter modules to said common grid power feed;
determine a number of said capacitors to switch into/out of a parallel connection across their respective said ac power outputs responsive to said total net level of ac power; and
send control data to said inverter modules to switch said determined number of capacitors into/out of said parallel connections.
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Abstract
We describe a modular adjustable power factor renewable energy inverter system. The system comprises a plurality of inverter modules having a switched capacitor across its ac power output, a power measurement system coupled to a communication interface, and a power factor controller to control switching of the capacitor. A system controller receives power data from each inverter module, sums the net level of ac power from each inverter, determines a number of said capacitors to switch based on the sum, and sends control data to an appropriate number of the inverter modules to switch the determined number of capacitors into/out of said parallel connection across their respective ac power outputs.
115 Citations
18 Claims
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1. A modular adjustable power factor renewable energy inverter system, the system comprising:
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a plurality of inverter modules, each inverter module having a dc power input and an ac power output; a common grid power feed coupled to each said inverter module ac power output; and a system controller having a communications link to each said inverter module to receive power data from the inverter module and to send control data to the inverter module, wherein each said inverter module further comprises; a series combination of a capacitor and a controllable switching device connected in parallel across said ac power output of the inverter module; a communication interface for communicating with said system controller; a power measurement system coupled to said communication interface to measure one or more parameters relating to a net level of ac power provided by the inverter module to said common grid power feed, and to provide power data to said communication interface for transmission to said system controller, wherein the power data defines said net level of ac power provided; and a power factor controller, coupled to said communication interface to receive control data from said system controller, and coupled to said controllable switching device to control said controllable switching device in response to said received control data to switch said capacitor into/out of parallel connection across said ac power output of said inverter module, wherein said system controller is configured to; receive said power data from each said inverter module; sum the net level of ac power from each said inverter module to determine a total net level of ac power provided by said plurality of inverter modules to said common grid power feed; determine a number of said capacitors to switch into/out of a parallel connection across their respective said ac power outputs responsive to said total net level of ac power; and send control data to said inverter modules to switch said determined number of capacitors into/out of said parallel connections. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of controlling power factor in a renewable energy inverter system, the inverter system comprising a plurality of inverter modules, each inverter module having a dc power input and an ac power output, wherein the ac power output of each said inverter module is coupled to a common grid power feed, each said inverter module having at least one reactive element switchable to be connected to the ac power output of the inverter module, the method comprising:
controlling a dissipation power factor of said inverter system by; monitoring the ac power provided to said common grid power feed by said plurality of inverter module to determine a total ac power provided to said common grid power feed by said plurality of inverter modules; determining a number of said inverter modules to control, dependent on a proportion of a maximum power output of said inverter system represented by said total ac power provided to said common grid power feed, wherein determining said number of said inverter modules to control comprises (i) setting said number to zero when said total ac power is below a threshold level proportion of said maximum power output and (ii) setting said number to increase monotonically with increasing total ac power above said threshold level proportion of said maximum power output; and controlling said determined number of inverter modules to switch said reactive elements of the inverter modules into the respective said ac power output to control a displacement power factor of said inverter system. - View Dependent Claims (16, 17, 18)
Specification