System and method for active/reactive power compensation
OwnerSuzan Eren, Majid Pahlevaninezhad +2inventors
InventorsSuzan Eren, Majid Pahlevaninezhad, Praveen Jain, Alireza Bakhshai
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Abstract
Systems, methods, and devices for use with active/reactive power control in power conditioning systems. To provide quick active/reactive power control by way of a grid-connected inverter, an estimator estimates the P and Q coefficients based on an instantaneous power from the grid-connected inverter. The estimator receives grid current and voltage and estimates of the P and Q coefficients are used with reference P and Q values to determine whether active or reactive power needs to be injected to the grid. The P coefficient is a DC offset of the instantaneous power of the grid and the Q coefficient is the coefficient of a sine component of the instantaneous power.
Claims13
A control system for controlling a power inverter, the system comprising:
- an active power subcontroller, said active power subcontroller receiving a difference between a reference P value and an estimated P value, an output of said active power subcontroller being used to determine voltage and current outputs of said power inverter;
- a reactive power subcontroller, said reactive power subcontroller receiving a difference between a reference Q value and an estimated Q value, an output of said reactive power subcontroller being used to determine voltage and current outputs of said power inverter;
- an active/reactive power estimator for estimating said estimated P value and said estimated Q value based on outputs of said power inverter, said estimator receiving voltage and current outputs of said power inverter;
- wherein said estimated P value is an estimate of a P value and said reference P value is a reference for said P value, said P value being a DC offset of an instantaneous power of a power grid to which said power inverter is connected and said estimated Q value is an estimate of a Q value and said reference Q value is a reference for said Q value, said Q value being a coefficient of a sine component of said instantaneous power of said power grid;
- and wherein said estimator estimates said estimated P value and said estimated Q value by implementing:
- {tilde over (p)}g,inst=pg,inst−[{circumflex over (θ)}−{circumflex over (P)} cos(2ωt)+{circumflex over (Q)} sin(2ωt)]
- {dot over ({circumflex over (P)})}=−γ2 cos(2ωt){tilde over (p)}g,inst
- {dot over ({circumflex over (Q)})}=γ3 sin(2ωt){tilde over (p)}g,inst
- where
- pg,inst is an instantaneous power for said grid;
- {circumflex over (P)} is an estimated value for said P value;
- {circumflex over (Q)} is an estimated value for said Q value;
- {tilde over (P)}g,inst is an estimation error for said instantaneous power for said grid;
- {circumflex over (θ)} is an estimated value for an unknown variable θ;
- {dot over ({circumflex over (P)})} is a derivative of said estimated value for said P value;
- γ2 and γ3 are system dependent coefficients;
- {dot over ({circumflex over (Q)})} is a derivative of said estimated value for said Q value.
Dependencies are inferred from the claim text.