Abstract: The disclosure relates to technology for providing power, voltage, and/or current from a combination of photovoltaic modules. In one aspect, a system has central power optimizer, which is located between a group of distributed power optimizers and a solar inverter. Each distributed power optimizer may be connected to the DC output of one photovoltaic modules, and may be used to regulate the power output of the photovoltaic module. The combined DC voltages of the distributed power optimizers may be provided to the input of the central power optimizer.

Abstract: A direct current (DC) bus voltage from a combined output of a plurality of DC power modules is controlled based on an alternating current (AC) voltage of a power grid. The DC bus voltage tracks the AC grid voltage to provide efficient conversion between the DC power sources and the AC grid, even when the amplitude of the AC grid voltage varies. In one example, a variable reference voltage is generated based on a detected AC grid voltage. The reference voltage increases and decreases in proportion to increases and decreases in the AC grid voltage. In this manner, large differences between the bus voltage and the grid voltage are avoided. By closely tracking the two voltages, efficiency in the modulation index for power conversion can be achieved.

Abstract: An apparatus includes an isolated power converter having an input connected to an input dc power source, a first output and a second output, and a non-isolated power converter having an input connected to the second output of the isolated power converter, wherein the first output of the isolated power converter and an output of the non-isolated power converter are connected in series.

Abstract: A switch circuit of a converter includes three switch units. A first switch unit includes a first switch device, a second switch device, a third switch device, and a fourth switch device that are connected in series. A second switch unit includes a fifth switch device and a sixth switch device that are connected in series. A third switch unit includes a seventh switch device and an eighth switch device that are connected in series. When the first switch device and the fifth switch device are switched on, the seventh switch is controlled to be switched on. When the fourth switch device and the sixth switch device are switched on, the eighth switch device is controlled to be switched on, thereby effectively reducing a conduction loss of the converter.

Abstract: A hybid resonant DC to DC converter uses an LLC or other resonant structure on the primary side, applying a two state waveform to one end of the resonant structure and a multi-state waveform to the other end of the resonant structure. The waveforms are at or near the resonant resonant frequency and the output voltage level is regulated by varying the shape of the multi-state waveform by varying the duty cycle of the switches used to generate it. The allows the converter to operate near or at its optimal resonant point, resulting in higher efficiency, over a wide range of regulated output voltage levels.

Abstract: According to one aspect of the present disclosure, there is provided an apparatus that includes a first power converter stage connected to a first side of a first transformer, and a second power converter stage connected to a first side of a second transformer. The apparatus further includes an interleaved multi-bridge circuit connected to the second side of the first transformer and to the second side of the second transformer. The apparatus further includes a controller that is configured to operate the interleaved multi-bridge circuit in a parallel mode in which the second sides of the first and second transformers are in parallel at a DC terminal of the interleaved multi-bridge circuit and in a series mode in which the second sides of the first and second transformers are in series at the DC terminal.

Abstract: A method includes generating a first ramp signal for controlling a first portion of a converter, generating a second ramp signal for controlling a second portion of the converter, controlling a state of a first switch of the first portion through comparing the first ramp signal to a control signal and a state of a first switch of the second portion through comparing the second ramp signal to the control signal and determining a switching cycle of the converter through comparing a current flowing through an inductor of the converter to a threshold.

Abstract: A DC to DC converter uses a multi-level boost converter topology. In addition to the input voltage being connected to an output node through a boost inductor in series with a pair of diodes, a bridge circuit generates a multi-level waveform on one side of flying capacitor, which is on the other side connected between the series connected diodes. The boost converter topology maintains low voltage stress on its components under abnormal conditions on the output node and allows for simple pre-charging of the flying capacitor.

Abstract: A method comprises operating a plurality of power optimizers connected in series between two input terminals of an inverter, wherein the plurality of power optimizers are connected to a plurality of solar panels to form a plurality of power modules connected in series, measuring operation parameters of the plurality of the solar panels, calculating a maximum power flow of each solar panel based upon the measuring, determining a mode transition range based upon the maximum power flows of the plurality of solar panels and configuring a first power optimizer to operate in a pass-through mode if a maximum power point tracking (MPPT) current of a first solar panel connected to the first power optimizer is within the mode transition range.

Abstract: An apparatus comprises an isolated power converter coupled to an input dc power source, wherein the isolated power converter comprises a first switch network coupled to a first transformer winding and a second switch network coupled to a second transformer winding and a non-isolated power converter coupled to the second switch network of the isolated power converter, wherein a current flowing through the non-isolated power converter is a fraction of a current flowing through the isolated power converter.

Abstract: A direct current (DC) bus voltage from a combined output of a plurality of DC power modules is controlled based on an alternating current (AC) voltage of a power grid. The DC bus voltage tracks the AC grid voltage to provide efficient conversion between the DC power sources and the AC grid, even when the amplitude of the AC grid voltage varies. In one example, a variable reference voltage is generated based on a detected AC grid voltage. The reference voltage increases and decreases in proportion to increases and decreases in the AC grid voltage. In this manner, large differences between the bus voltage and the grid voltage are avoided. By closely tracking the two voltages, efficiency in the modulation index for power conversion can be achieved.

Abstract: A method comprises during a first half cycle, configuring a first switch to operate as an always-on switch, turning on a second switch prior to turning on a third switch and turning off the third switch prior to turning off the second switch, wherein the first switch and the second switch are connected in series and further in parallel with the third switch between a first terminal of a power source and a filter and during a second half cycle, configuring a fourth switch to operate as an always-on switch, turning on a fifth switch prior to turning on a sixth switch and turning off the sixth switch prior to turning off the fifth switch, wherein the fourth switch and the fifth switch are connected in series and further in parallel with the sixth switch between a second terminal of the power source and the filter.

Abstract: A converter comprises a first switching element and a second switching element coupled between an input power source and an output capacitor and an inductor coupled to a common node of the first switching element and the second switching element, wherein the second switching element comprises a first diode and a first switch connected in series between a first terminal and a second terminal of the second switching element and a second diode connected between the first terminal and the second terminal of the second switching element.

Abstract: A system includes a first inverter connected between a de power source and an input terminal of a first leg of a coupled inductor, a second inverter connected between the de power source and an input terminal of a second leg of the coupled inductor, a third inverter connected between the de power source and an input terminal of a third leg of the coupled inductor, and an output filter connected between the coupled inductor and an ac power source, wherein output terminals of the first leg, the second leg and the third leg of the coupled inductor are connected together and further connected to the output filter.

Abstract: A system comprises a first five-level inverter connected between a dc power source and an ac grid, a second five-level inverter connected between the dc power source and the ac grid and a third five-level inverter connected between the dc power source and the ac grid, wherein each five-level inverter comprises a first boost apparatus and a second boost apparatus.

Abstract: A method comprises detecting an input voltage and an output voltage of a buck-boost converter, wherein the buck-boost converter comprises a first high-side switch and a first low-side switch connected in series across an input capacitor, a second high-side switch and a second low-side switch connected in series across an output capacitor and an inductor coupled between a common node of the first high-side switch and the first low-side switch, and a common node of the second high-side switch and the second low-side switch and configuring the buck-boost converter such that at least one of the first high-side switch and second low-side switch operates at a fixed duty cycle mode.

Abstract: An embodiment holdup time circuit of a bridgeless power factor correction circuit comprises a charge device connected between an output terminal of a bridgeless power factor correction circuit and an energy storage apparatus, a discharge device connected between the energy storage apparatus and an input of the bridgeless power factor correction circuit, the energy storage apparatus and the bridgeless power factor correction circuit comprising a first boost converter, a second boost converter, a first switch and a second switch, wherein the first switch is connected between the first boost converter and ground and the second switch is connected between the second boost converter and ground.

Abstract: A system comprises a plurality of inverter units having inputs connected to a power source and a coupled inductor comprising a plurality of windings and coupled between the plurality of inverter units and an output filter, wherein each winding of the plurality of windings has a first terminal connected to an output of a corresponding inverter unit and second terminals of the plurality of windings are connected together.

Abstract: A system comprises a five-level rectifier configured to be connected with an ac power source, wherein the five-level rectifier comprises a first boost apparatus and a first buck apparatus configured to operate in a first half cycle of the ac power source, and a second boost apparatus and a second buck apparatus configured to operate in a second half cycle of the ac power source and a five-level inverter connected to the five-level rectifier.

Abstract: According to one aspect of the present disclosure, there is provided an apparatus that includes a first power converter stage connected to a first side of a first transformer, and a second power converter stage connected to a first side of a second transformer. The apparatus further includes an interleaved multi-bridge circuit connected to the second side of the first transformer and to the second side of the second transformer. The apparatus further includes a controller that is configured to operate the interleaved multi-bridge circuit in a parallel mode in which the second sides of the first and second transformers are in parallel at a DC terminal of the interleaved multi-bridge circuit and in a series mode in which the second sides of the first and second transformers are in series at the DC terminal.