Battery energy storage control systems and methods
AssigneeThe Regents of the University of California
InventorsRajit Gadh, Hamidreza Nazaripouya, Chi-Cheng Chu
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Abstract
A distributed control system uses a central controller in Internet communication with a local controller to manage grid tie attachment with a battery to form an integrated battery energy storage system (BESS). The BESS is capable of charging or discharging the battery, as well as correcting grid phase with volt amp reactive (VAR) leading or lagging operation modes. Examples shown include simple BESS charging and discharging, BESS integrated with renewable energy sources (here photovoltaic), and direct current fast charge (DCFC) connections with an electric vehicle.
Claims21
A battery energy storage system (BESS), the system comprising:
- (a) a central controller computer;
- (b) a non-transitory memory storing instructions executable by the central computer;
- (c) a local controller computer;
- (d) a non-transitory memory storing instructions executable by the local computer;
- (e) wherein said central controller instructions and said local controller instructions, when respectively executed by the central controller computer and the local controller computer allow for a communications interface configured for network communications therebetween;
- (f) a control system computer comprising the local controller computer and the central controller computer;
- (g) a grid tie inverter, comprising:
- (1) a port for connection to an electrical grid;
- (2) a port for connection to a battery;
- and
- (3) a communications interface configured for communications with the control system;
- and
- (h) wherein said central controller and said local controller instructions, when executed among the local controller computer and the central controller memory, form a set of operational instructions performing steps comprising:
- (1) controlling communication between the central controller computer and the local controller computer;
- (2) executing a safety features control section;
- and
- (3) executing an operation control and monitoring section.
A non-transitory medium storing instructions executable by a computer processor, said instructions when executed by the computer processor performing steps comprising:
- (a) collecting an historical power series;
- (b) decompositing the historical power series into a constitutive series through wavelet transformations;
- (c) modeling each of the constitutive series by a plurality of Auto-Regressive Moving Average (ARMA) models for recognition of their linear patterns, whereby a plurality of ARMA models are produced;
- (d) recompositing an estimated series obtained from the plurality of ARMA models for each constitutive series through an inverse wavelet transform;
- (e) compensating for an error of the wavelet transformation and ARMA model predictions by recurrent neural networks through capturing of nonlinear patterns buried in a difference between the historical power series and the estimated series, whereby a time series estimate is produced.
A method for performing a hybrid optimization, the method comprising:
- (a) collecting an historical power series;
- (b) decompositing the historical power series into a constitutive series through wavelet transformations;
- (c) modeling each of the constitutive series by a plurality of Auto-Regressive Moving Average (ARMA) models for recognition of their linear patterns, whereby a plurality of ARMA models are produced;
- (d) recompositing an estimated series obtained from the plurality of ARMA models for each constitutive series through an inverse wavelet transform;
- and
- (e) compensating for an error of the wavelet transformation and ARMA model predictions by recurrent neural networks through capturing of nonlinear patterns buried in a difference between the historical power series and the estimated series;
- (f) wherein said method is performed by a computer processor executing instructions stored on a non-transitory computer-readable medium.
A non-transitory medium storing instructions executable by a computer processor, said instructions when executed by the computer processor performing steps comprising:
- (a) designing a low-pass finite impulse response (FIR) filter with minimum-length, minimum-phase, and low-group-delay;
- (b) initializing a cut-off frequency ωc a maximum possible filter length Nmax, and an error bound ϵ;
- (c) solving the problem:
- minimize N subject to
- ∥Akx∥2≤0.7079 (−3 dB) kϵI, I={k|ωk≥ωc} as a quasiconvex optimization problem by using a bisection feasibility problem method;
- (d) solving a second-order cone programming (SOCP) problem by defining parameters
- minh[n](t1+αt2)
- such that, |Akx∥2≤t1
- ∥Bx∥2≤t2∥
- Cx=d
- where 0≤ω1≤ω2≤ . . . ≤ωk≤π, k=1, . . . , M;
- (1) by initially setting α=0;
- (2) solving the SOCP problem;
- (3) incrementing α by 1 until all zeroes are inside the unit circle;
- (4) determining if the group delay (grd) of
- max
-
- (
- grd
- )
- =
- r
- 1
- +
- r
- is feasible;
- (i) if feasible, then setting u=t;
- (ii) if not feasible, then setting l=t;
- and
- (5) repeating until u−l≤ϵ.
A method for designing a low-pass finite impulse response (FIR) filter with minimum-length, minimum-phase, and low-group-delay, the method comprising:
- (a) initializing a cut-off frequency ωc, a maximum possible filter length Nmax, and an error bound ϵ;
- (b) solving the problem:
- minimize N subject to
- ∥Akx∥2≤0.7079 (−3 dB) kϵI, I={k|ωk≥ωc)} as a quasiconvex optimization problem by using a bisection feasibility problem method;
- (c) solving a second-order cone programming (SOCP) problem by defining parameters
- minh[n](t1+αt2)
- such that. |Akx∥2≤t1
- |Bx∥2≤t2∥
- Cx=d
- where 0≤ω1≤ω2≤ . . . ≤ωk≤π, k=1, . . . , M;
- (1) by initially setting α=0;
- (2) solving the SOCP problem;
- (3) incrementing a by 1 until all zeroes are inside the unit circle;
- (4) determining if the group delay (grd) of
- max
-
- (
- grd
- )
- =
- r
- 1
- +
- r
- is feasible;
- (i) if feasible, then setting u=t;
- (ii) if not feasible, then setting l=t;
- and
- (5) repeating until u−l≤ϵ;
- (d) wherein said method is performed by a computer processor executing instructions stored on a non-transitory computer-readable medium.
A battery energy storage system (BESS), comprising:
- (a) a control system computer;
- (b) a non-transitory memory storing instructions executable by the control system computer;
- (c) a grid tie inverter, comprising:
- (1) a port for connection to an electrical grid;
- (2) a port for connection to a battery;
- and
- (3) a communications interface configured for communications with the control system;
- and
- (d) wherein said instructions executable by the control system computer perform steps comprising:
- (1) executing a safety features control section;
- and
- (2) executing an operation control and monitoring section.
Dependencies are inferred from the claim text.