Abstract: Systems and methods for providing AC power to a power grid using renewable energy sources as well as energy storage devices. A control system controls multiple DC/DC converters that are coupled to renewable energy sources as well as to one or more energy storage devices. The control system also controls the charge/discharge of the energy storage devices. Each DC/DC converter control block in the control system automatically detects whether to perform MPPT on the renewable energy source or to control the discharge of the energy storage devices. Each DC/DC converter control block ensures that power from the renewable energy source or from the energy storage device is converted and provided to the power grid.

Abstract: Systems and methods for use with renewable energy resources that provide power to an energy power grid or to one or more motor loads. A control system along with an energy storage/combiner block and a DC/AC inverter is used to condition DC power received from renewable energy sources. The control system receives current and voltage outputs from the inverter along with values indicating current and voltage outputs directly from the renewable energy sources. These are then used to estimate and control motor speed when the system is in the off-grid mode. In addition, the control system uses these inputs to provide the gate pulses that are used to control the three phase AC output power from the inverter.

Abstract: Systems and methods relating to power inverters for power generation systems. A power inverter suitable for renewable power sources is configured with a data processing module that receives power related data from a power grid and from a battery backup inverter. The data processing module calculates mode of operation data based on the power related data and, if the mode of operation data exceeds a threshold, then the power generation system is operating in an off-grid mode (i.e. the system is decoupled from the power grid). If the mode of operation data is equal or less than the threshold, then the power generation system is operating in an on-grid operating mode. The system is also self-tuning with respect to the threshold value.

Abstract: Systems, methods, and devices relating to the extraction of parameters for a grid voltage. A multi-block hybrid PLL or hybrid observer receives grid voltage. The grid voltage is received by a harmonic/noise decomposer block which separates the harmonic/noise component of the incoming voltage from the clean voltage signal. The clean voltage signal is then output from the PLL/observer. The clean voltage signal is also sent to an amplitude estimator block which estimates the amplitude of the clean voltage signal. The harmonic/noise component of the input voltage signal is sent, along with the clean voltage signal, to a frequency estimator block. The frequency estimator block then determines the phase angle of the incoming signal as well as the frequency of the incoming voltage signal.

Abstract: Systems, methods, and devices relating to the control of power conditioning systems. For a micro-inverter, a controller block controls the DC/DC converter while a separate controller block controls the DC/AC inverter. A dynamic maximum efficiency tracker (DMET) control block receives state variable outputs from the converter and the inverter. The control block then perturbs specific control input parameters for the converter and the inverter and determines the effect of the perturbation on the converter and inverter efficiencies and on micro-inverter efficiency as a whole. If the efficiency decreases, then the direction of the perturbation is reversed. Other system control tasks, such as maximum power point tracking and DC-bus voltage regulation can be performed concurrently by adjusting other control input parameters.

Abstract: Systems, methods, and devices relating to inverters. A control system for use with photovoltaic panel coupled inverters controls the function and operation of the inverter based on the voltage at the point of common coupling. The inverter is operated in either current control mode or in voltage control mode based on whether or not the inverter is coupled to a grid or whether other energy sources are available to control the voltage at the point of common coupling.

Abstract: Provided are DC-bus voltage or DC-bus current controller methods and circuits, for a voltage or current source inverter. A mean value calculator provides an output signal comprising the mean value of the DC-bus voltage or current, which is used as a feedback signal in a closed loop of the voltage or current source inverter controller, such that a ripple in the DC-bus voltage or current is substantially prevented from entering the closed-loop. In some embodiments a droop controller, which may be adaptive, is used in the closed loop with reverse proportional gain. The adaptive droop controller may provide a constant or variable DC-bus voltage or current. Embodiments regulate the DC-bus voltage or current to an optimized value such that power losses for load and grid conditions are minimized or reduced, and voltage and current ripple is minimized.

Abstract: Systems, methods, and devices relating to a DC/AC inverter. The inverter has a full bridge converter and an output filter with an integrated magnetic subcircuit. The subcircuit has main and auxiliary inductors and is designed to steer the current ripple of the inverter's output to the power semiconductors in the full bridge converter. By doing so, zero voltage switching is achieved by the power semiconductors, thereby mitigating switching losses. At the same time the current ripple in the inverter's output is attenuated.

Abstract: Systems, methods, and devices which eliminate the DC current from the output of grid-connected inverters. A current controller is provided which interfaces with a grid-connected DC/AC inverter. The current controller uses a nonlinear adaptive filter which receives, as input, the output current of the inverter along with grid current frequency. The nonlinear adaptive filter estimates the DC value of the grid current and, in conjunction with an integrator, removes this DC current component. This is done by adjusting the duty cycle of the grid-connected inverter.

Abstract: Systems, methods, and devices for use in a DC/DC converter. A circuit uses a full-bridge power semiconductor subcircuit along with a high power transformer subcircuit, a diode bridge subcircuit, and a parallel capacitor to provide galvanic isolation and boost the voltage from a power source such as a photovoltaic panel. To ensure zero voltage switching for the power semiconductors, either a passive auxiliary subcircuit or an inductor coupled in parallel to a transformer in the transformer subcircuit may be used. A controller which derives its timing signals from the transformer primary current is used to control the timing of the power semiconductors in the circuit. The circuit and its controller allows for self-adjusting regardless of load and uses the entire switching cycle to be used for power transfer.

Abstract: Systems, methods, and devices relating to power converters. A power conditioning system uses multiple DC/DC power converter blocks. The output of each of the converter blocks is received by an energy storage and combiner block. The output of the combiner block is then received by a DC/AC inverter. The various components of the power conditioning system are controlled by a central controller. The power semiconductors within each DC/DC converter are controlled by a subsystem of the central controller and MPPT is also provided by the central controller. Also provided for are a novel three-phase DC/AC inverter topology with reduced output ripple and a control scheme for controlling the power semiconductors in the DC/AC inverter.

Abstract: Systems, methods, and devices relating to the use of multiple DC power generation sources with DC/DC converters to thereby provide AC power suitable for provision to a power grid. Multiple DC power generation sources are each coupled to an input stage with a DC/DC converter. All the DC/DC converters in the multiple input stages are controlled by a single digital controller. Within the single digital controller are controller sub-blocks, each of which generates control signals for a specific DC/DC converter. Each controller sub-block provides multiple functions for improving the performance of the system as a whole.

Abstract: Provided herein is a single phase power system controller and a method for controlling a single phase power system. The single phase power system controller comprises an error signal generator that generates an error signal from an instantaneous power reference signal and a measured instantaneous output power signal corresponding to the power delivered to a power distribution grid; and a modulator that modulates the error signal according to a trigonometric function of the grid voltage phase angle and produces a control signal for an inverter controller. In accordance with the circuits and methods provided herein, real and reactive power delivered to the grid are controlled simultaneously based on instantaneous output power feedback.

Abstract: Provided are methods and circuits for a controller for a control system, comprising first and second control loops that operate substantially independently, wherein the first control loop is an amplitude control loop and the second loop is a phase or frequency control loop. In some embodiments the amplitude control loop operates at an amplitude that is proportional to an amplitude of an input signal at a fundamental system frequency and at a selected harmonic of a fundamental system frequency; and the frequency control loop operates at a fundamental system frequency and at a selected harmonic of the fundamental system frequency. The frequency control loop may adaptable to a fundamental control system frequency or to a selected harmonic of the fundamental control system frequency. The controller may be implemented as a resonant controller and used in various ac systems, and offers high structural robustness in digital implementations.

Abstract: Systems, methods, and devices relating to control systems for grid-connected inverters. Because grid conditions may vary and because control system stability is dependent on the parameters of the components within the inverter, the present invention adaptably monitors the varying values of these components. Based on the sensed values and on predicted values, controller gains are adaptably adjusted to maintain system stability.

Abstract: Described herein are methods, systems, and apparatus for a controller for a power circuit that interfaces distributed power generation with a power distribution grid, comprising: a first portion, including a maximum power point tracker, that receives signals corresponding to the distributed power generation voltage and current, and outputs to the power circuit a signal for controlling the voltage of the distributed power generation; a second portion, including a current reference generator, a current controller, and a dc voltage controller, that receives signals corresponding to a dc voltage of the power circuit, the power distribution grid voltage and current, and the inverter current, and outputs signals for controlling the power circuit output voltage; wherein the current reference generator includes nonlinear circuit elements and generates a current reference signal from the dc voltage of the power circuit and the grid voltage and current; such that substantially harmonic-free power is injected into the p

Abstract: Provided are single phase and multiple phase DC-AC inverters with soft switching, and related methods and uses. The DC-AC inverters comprise at least one voltage source inverter circuit or at least one current source inverter circuit having a DC input and an AC output including a first component at a fundamental frequency and a ripple component at a frequency higher than the fundamental frequency; wherein the ripple component is of a sufficient magnitude that the voltage source inverter circuit output current reverses polarity and allows the at least one inverter circuit to operate with zero voltage switching; or wherein the ripple component is of a sufficient magnitude that the current source inverter circuit output voltage reverses polarity and allows the at least one inverter circuit to operate with zero current switching. The circuits and methods may be used with grid-connected renewable energy sources.

Abstract: Provided is a maximum power point (MPP) tracker for a PV cell inverter, and a PV cell inverter. The MPP tracker decouples output power oscillations from the input power generation and extracts maximum available power from the PV cell. The PV cell inverter uses the MPP tracker and generates a sinusoidal output current from the MPP tracker output. The sinusoidal output current may be fed to a power distribution grid. The PV cell inverter may use a pulse width modulation technique to cancel harmonics in the sinusoidal output current. The circuits use a minimum number of components and avoid use of large electrolytic capacitors.

Abstract: The invention provides a digital active EMI filter that removes, minimizes, or reduces unwanted interference (i.e., EMI noise) generated by a power circuit such as, for example, a power converter. Digital active filtering includes digital sampling of the incident noise signal amplitude and frequency, discrete time conversion of the EMI noise source, processing (e.g., inverting) the digital signal, and then constructing an analog output signal (i.e., an EMI compensation signal) which is injected to the input of the power circuit. A digital EMI filter as described herein may be used in both differential-mode and common-mode configurations, and overcomes limitations of passive and active analog EMI filters.

Abstract: Provided herein is a single phase power system controller and a method for controlling a single phase power system. The single phase power system controller comprises an error signal generator that generates an error signal from an instantaneous power reference signal and a measured instantaneous output power signal corresponding to the power delivered to a power distribution grid; and a modulator that modulates the error signal according to a trigonometric function of the grid voltage phase angle and produces a control signal for an inverter controller. In accordance with the circuits and methods provided herein, real and reactive power delivered to the grid are controlled simultaneously based on instantaneous output power feedback.