Abstract: A bidirectional buck-boost converter includes at least one soft-switching cell to reduce switching losses by providing soft-switching of all semiconductor devices. A soft-switching cell comprises an active switch coupled in series with an inductor, a two-winding transformer, and a reset-voltage circuit. The soft-switching cells enable the buck and boost rectifiers to turn off with a controlled turn-off rate of their current to minimize their reverse-recovery losses, the power-controlling buck and boost switch to turn on with zero-voltage switching (ZVS), and the switch of the soft-switching cell to turn off with zero-current switching (ZCS).

Abstract: Control methods for resonant converters offer improved performance in resonant converters that operate with a wide input-voltage range or a wide output-voltage range (or both) by substantially reducing the switching-frequency range. Reduction in the switching frequency range is achieved by controlling the output voltage with a combination of variable-frequency control and time-delay control. Variable-frequency control may be used to control the primary switches of an isolated resonant converter, while delay-time control may be used to control secondary-side rectifier switches provided in place of diode rectifiers. The secondary-side control may be implemented by sensing the secondary current or the primary current (or both) and by delaying the turning-off of the corresponding secondary switch with respect to the zero crossings in the secondary current or the primary current.

Abstract: A power converter topology is adapted for efficiency according to input voltage, output voltage or output current conditions. Topology adaptation is achieved by control responsive to the input and output operating conditions, or to one or more external control signals. Transition between any two topologies is implemented by pulse width modulation in the two switches in one of two bridge legs of a full bridge converter. When transitioning from full-bridge to half-bridge topology, the duty ratio of one switch in one leg of the full bridge is increased, while simultaneously the duty ratio of the other switch in the same leg is reduced until one switch is continuously on, while the other switch is continuously off. The transition from the half-bridge to the full-bridge topology is accomplished by modulating the same switches such that, at the end of the transition, both switches operate with substantially the same duty cycle.

Abstract: A low input-current-harmonic three-phase three-level boost rectifier includes an input stage for receiving a three-phase input voltage in relation to a neutral node and an output stage adapted to couple to at least one load. The rectifier further includes one or more switching converter stages, each having a plurality of serially-connected switches coupled to the neutral node, one of the serially-connected switches operating with a fixed duty cycle while the other of the serially-connected switches operating with a variable duty cycle, the fixed duty cycle being a substantially 50% duty cycle and the variable duty cycle being less than or equal to a substantially 50% duty cycle. The serially-connected switches are coupled to clamping diodes and clamping capacitors.

Abstract: The present invention relates to a power management system comprising at least one power management subsystem. Each power management subsystem comprises a first power module coupled to a first load and comprising at least one first power supply for supplying power to the first load; a second power module coupled to a second load and comprising at least one second power supply, wherein at least one second power supply is retractably installed in the second power module and selectively coupled to the second load; and a pass-through module comprising at least one pass-through unit retractably installed in the second power module to replace with the at least one second power supply and selectively connecting the first power module to the second load for allowing the first power module to supply power to the second load.

Abstract: A power supply having an input and an output, includes a power converter coupled between the input and output of the power supply including at least one switch that is controlled by comparing a sensed voltage, the sensed voltage corresponding to a current flowing through the switch, to a reference voltage. A controller, in response to a change detected in a switching frequency of the switch, reduces audible noise generated by the power supply by at least one of: adjusting the reference voltage; adjusting the current sense voltage; or adjusting a resistance used to generate the sensed voltage.

Abstract: The current invention provides a power supply that includes an igniter that generates an ignition voltage for igniting a DC lamp; an auxiliary power stage that outputs an auxiliary voltage for sustaining sufficient current in the DC lamp after the DC lamp is ignited; a voltage conversion stage coupled to the auxiliary power stage and generating a voltage at a level that is higher than the auxiliary voltage; and a switch that couples the auxiliary voltage to the DC lamp and the voltage conversion stage for a predefined period of time.

Abstract: The present invention relates to a power management system comprising at least one power management subsystem. Each power management subsystem comprises a first power module coupled to a first load and comprising at least one first power supply for supplying power to the first load; a second power module coupled to a second load and comprising at least one second power supply, wherein at least one second power supply is retractably installed in the second power module and selectively coupled to the second load; and a pass-through module comprising at least one pass-through unit retractably installed in the second power module to replace with the at least one second power supply and selectively connecting the first power module to the second load for allowing the first power module to supply power to the second load.

Abstract: A PFC rectifier comprises a first converter having a first output capacitor and a second converter having a second output capacitor. The first and second capacitors are coupled to each other to increase the output voltage of the PFC rectifier. For example the first or second output capacitors can be serially coupled to each other. At least one or both of the first or second converters comprise buck or buck-boost converters, including inverting or non-inverter buck converters. The first and second converters can also form a bi-directional ac-ac inverter.

Abstract: A power converter system supplies power to one or more loads. The power converter system comprises at least one power converter operating at a desired efficiency; and a power storage system coupled to the at least one power converter for receiving power supplied from the at least one power converter and storing power therein when the at least one power converter operates at an efficiency that is below the desired efficiency.

Abstract: A power supply having an specified hold-up time to take a input voltage and convert it to an output voltage, comprising: a first power stage to receive the input voltage; a second power stage to generate the output voltage and an output current; an intermediate charge storage device coupled between the first and second power conversion stages providing an intermediate output voltage in response to the input voltage; and a controller that controls the intermediate output voltage according to a voltage function that is associated with the hold-up time.

Abstract: A ballast according to the present invention operates in an ignition state, a warm-up state, and a steady state for igniting and powering a lamp. The ballast comprises an igniter that ignites the lamp during the ignition state and a switching power inverter, for example, a full bridge DC-AC inverter implemented with MOSFET switching transistors, that powers the lamp during the warm-up and steady states. The switching power inverter, which drives the igniter, operates at a first switching frequency during the ignition state and operates at a second switching frequency during the steady state. Preferably, the first switching frequency, which in one exemplary embodiment is in the kHz range, is higher than the second switching frequency.

Abstract: A soft-switched, full-bridge pulse-width-modulated converter and its variations provide zero-voltage-switching conditions for the turn-on of the bridge switches over a wide range of input voltage and output load. The FB PWM converters of this invention achieve ZVS with a substantially reduced duty cycle loss and circulating current. The ZVS of the primary switches is achieved by employing an auxiliary circuit having an inductor and transformer to store energy for ZVS turn-on of the bridge switches.

Abstract: A high-performance contactless electrical energy transmission (CEET) technique which employs the inductive energy transmission principle is described. The proposed technique enables the implementation of high-efficiency, high-power-density, fully-regulated CEET systems suitable for applications with a wide input range and a wide load range. The CEET system in this invention consists of an input-side variable-frequency inverter and an output-side regulated rectifier. A high efficiency of the system is achieved by recovering the energy stored in the leakage inductances of the transformer by incorporating them in the operation of the circuit, and by employing high-frequency-inverter and controlled-rectifier topologies that allow a controlled bi-directional power flow through the transformer. A feed forward, variable-switching-frequency control of the inverter is used to maintain a substantially constant power transfer through the transformer when the input voltage changes.