System and method for controlling synchronous rectification. For example, a system for controlling synchronous rectification includes: a first control-signal generator configured to generate a first control signal; a second control-signal generator configured to receive the first control signal for a first switching cycle and generate a second control signal for a second switching cycle based at least in part on the first control signal for the first switching cycle, the first switching cycle preceding the second switching cycle; and a driver configured to receive the first control signal and generate a drive voltage based at least in part on the first control signal; wherein the second control-signal generator is further configured to: process information associated with the first control signal; determine a first time duration when the first control signal remains at a first logic level during the first switching cycle.

An example power system for supplying AC output power to an AC load includes: a variable-speed generator configured to be driven by a prime mover, the generator comprising a first winding and a reference tap in the first winding; a rectifier configured to rectify an input voltage from the first winding to output a positive DC signal with respect to the reference tap and a negative DC signal with respect to the reference tap; a first boost converter configured to convert the positive DC signal to generate a positive DC bus voltage with respect to the reference tap; a second boost converter configured to convert the negative DC signal to generate a negative DC bus voltage with respect to the reference tap; and an inverter circuit configured to convert the positive DC bus voltage and the negative DC bus voltage to an AC output signal with respect to the reference tap.

A thermostat system for control of an HVAC (Heating, Ventilation and Air-Conditioning) system, the thermostat system comprising a power conversion module, the power conversion module further comprising a power input of either a direct-current voltage or an alternating-current voltage, a battery management system including a battery and a battery management circuit, the battery management circuit configured to select either the battery output voltage or the primary output voltage based on an operating condition, a communication module, a temperature monitor, one or more environmental sensors, a graphical user interface display, and a processor.

A thermostat system for control of an HVAC (Heating, Ventilation and Air-Conditioning) system, the thermostat system comprising a power conversion module, the power conversion module further comprising a power input of either a direct-current voltage or an alternating-current voltage, a battery management system including a battery and a battery management circuit, the battery management circuit configured to select either the battery output voltage or the primary output voltage based on an operating condition, a communication module, a temperature monitor, one or more environmental sensors, a graphical user interface display, and a processor.

An the LED driving circuit, for driving an the LED load, includes: a bridge rectifier for rectifying an AC input voltage into a DC voltage; a serial capacitor voltage divider coupled to the bridge rectifier, including a plurality of serial capacitors; a half-bridge switch, coupled to the serial capacitor voltage divider; and a controller coupled to the half-bridge switch, for determining whether the DC voltage is higher than a threshold value and for controlling the half-bridge switch in a full-voltage mode or a half-voltage mode. In the full-voltage mode, the plurality of serial capacitors of the serial capacitor voltage divider synchronously supply power to the LED load. In the half-voltage mode, the plurality of serial capacitors of the serial capacitor voltage divider alternatively supply power to the LED load.

A system for manufacturing a part, the system comprising a power source, a rectifier, an electrical conduit, and a framework. The power source is configured to generate a high frequency, high current electrical signal. The rectifier is configured to convert the electrical signal to a direct current electrical signal. The electrical conduit is configured to carry the electrical signal. The framework is formed of electrically resistive metal having a relatively high melting point and is connected to the electrical conduit and at least partially encased in a powdered metal having a melting point lower than the melting point of the framework so that transmission of the electrical signal through the framework transitions at least some of the powdered metal into its molten state so that at least some of the molten metal cooled into its solidified state forms at least a portion of the part.

A system for manufacturing a part, the system comprising a power source, a rectifier, an electrical conduit, and a framework. The power source is configured to generate a high frequency, high current electrical signal. The rectifier is configured to convert the electrical signal to a direct current electrical signal. The electrical conduit is configured to carry the electrical signal. The framework is formed of electrically resistive metal having a relatively high melting point and is connected to the electrical conduit and at least partially encased in a powdered metal having a melting point lower than the melting point of the framework so that transmission of the electrical signal through the framework transitions at least some of the powdered metal into its molten state so that at least some of the molten metal cooled into its solidified state forms at least a portion of the part.

According to the present embodiment, a DC transformation system includes a rectifier, a first power conversion device, a second power conversion device, and a control device. The rectifier rectifies AC power supplied from an AC power source and outputs a first DC voltage. The first power conversion device is connected in series to the rectifier and outputs a second DC voltage. The second power conversion device is connected in parallel to the rectifier and converts power supplied from the rectifier to supply the converted power to the first power conversion device. The control device controls the first power conversion device to cause an addition/subtraction voltage of the first DC voltage and the second DC voltage to be a predetermined voltage.

According to the present embodiment, a DC transformation system includes a rectifier, a first power conversion device, a second power conversion device, and a control device. The rectifier rectifies AC power supplied from an AC power source and outputs a first DC voltage. The first power conversion device is connected in series to the rectifier and outputs a second DC voltage. The second power conversion device is connected in parallel to the rectifier and converts power supplied from the rectifier to supply the converted power to the first power conversion device. The control device controls the first power conversion device to cause an addition/subtraction voltage of the first DC voltage and the second DC voltage to be a predetermined voltage.

A power supply circuit that outputs an electric power input from a vibration-driven energy harvesting element to an external load includes a rectifying circuit that rectifies an alternating current power input from the vibration-driven energy harvesting element; a first capacitor that accumulates a power output from the rectifying circuit; a chopper circuit that has a switching element controlling a chopper timing and has an input terminal connected to the first capacitor; and a control signal generation unit that supplies a control signal to the switching element, wherein: the control signal generation unit generates the control signal without referring to a voltage of the first capacitor.