Abstract: An apparatus for reducing the heat losses caused by the DC Bus capacitor current is proposed. The apparatus includes: a double frequency boost converter circuit having two boost converter circuits coupled in parallel, in which two switches, respectively disposed on the two boost converter circuits, are turned on and off alternately to produce an output current having a frequency twice that of control signals of the two switches, and to offer a DC bus respectively, a full-bridge DC-DC converter coupled to an output terminal of the double frequency boost converter circuit for transforming an output of the DC bus to a DC voltage, and a DC bus capacitor coupled to the double frequency boost converter circuit and the full-bridge DC-DC converter in parallel for balancing two corresponding transient powers of the double frequency boost converter circuit and the full-bridge DC-DC converter respectively.

Abstract: An energy-feedback clamping circuit of a power converter is proposed. The converter includes a transformer coupled to a full-wave rectifier circuit. The clamping circuit includes: two clamping diodes having two anodes coupled to each other at a common-anode terminal and two cathodes coupled to two terminals of a secondary winding of the transformer, a first clamping capacitor having a first terminal coupled to a cathode of a first rectifying diode of the rectifier circuit and a second terminal coupled to the common-anode terminal, a second clamping capacitor having a first terminal coupled to a connecting node of the output filtering inductor and capacitor of the rectifier circuit and a second terminal coupled to the common-anode terminal, and a converter circuit having an input terminal coupled to the second clamping capacitor and an output terminal for offering a power source.

Abstract: A parallel inverter system includes a plurality of inverters of an instantaneous voltage control type, an output bus, an active power bus, a phase bus, and controlling devices. The output bus is used for connecting outputs of said plurality of inverters to a load. The active power bus is connected to the plurality of inverters so as to provide an active power sharing reference. The phase bus is connected to the plurality of inverters so as to provide a system phase reference. And, controlling devices control sinusoidal wave references of inverters to have the same phase, the reactive power, and the active power responsive to the active power sharing reference and the system phase reference. The related methods are also discussed.

Abstract: In a boost converter, an energy recycle circuit can be normally operated only when the output voltage is larger than the input voltage. In certain cases, such as when the output is in the abnormal operation, the output voltage could be equal to or less than the input voltage so that the current on the inductor of the energy recycle circuit would be increased to damage the switch element of the energy recycle circuit, and then the rectifying diodes of the boost converter would be damaged too. The present invention relates to a simple auxiliary circuit including a controllable voltage source for resetting the inductor of the energy recycle circuit under the abnormal operation so as to protect the boost converter and to improve the safety of the power supply.

Abstract: In those conventional arts, a DC/DC converter with secondary clamp circuit has a problem of voltage oscillation, and a DC/DC converter with primary clamp circuit has problems of heat and clamping losses due to larger forward and reverse currents passing the primary clamp circuit. The present invention applies a tapped inductor or a set of coupling inductors to a DC/DC converter with primary clamp circuit for reducing the voltage oscillation, and furthermore to decrease the forward and reverse current passing through the clamp circuit for reducing the clamping losses of the clamp circuit.

Abstract: In the UPS and communication power supply system, the output voltage of the PFC circuit is relativly high. The phenomenon of reverse recovery is also relativly serious for the use of a high voltage diode. A simple L-D snubber, which is suitable for PFC circuit of every kind of power system is provided for suppressing the phenomenon of reverse recovery of the diode so as to reduce all kinds of switch loss caused by the phenomenon and improve the efficiency of power system.

Abstract: A cross regulation controller and the methods for controlling a boost converter are proposed. The boost converter includes the first and second switch elements, and the first and second output capacitors. The cross regulation controller includes a first feedback control circuit for processing the second voltage, a sampling of the voltage across the second output capacitor, with a reference voltage to produce a third voltage and to transform the third voltage to generate a first pulse signal to drive the first switch element, and a second feedback control circuit for processing the first voltage, a sampling of the voltage across the first output capacitor, with a reference voltage to produce a fourth voltage and to transform the fourth voltage to generate a second pulse signal to drive the second switch element so as to achieve a balancing status between the first voltage and the second voltage.

Abstract: The invention relates to an apparatus and a method for detecting a current direction in a PWM converter or an inverter having one or more upper and lower arms, each of which consists of a switching device with an anti-parallel diode. The voltage across the switching device presents a different value and a polarity that depend on the direction of the current flowing through the switching device, wherein the current direction is acquired by sampling this voltage in the period of the trigger signal being on. In a case of small current, this sampled voltage value is relatively large to the flowing current magnitude and is easy to be distinguished. Furthermore, this invention presents a method for obtaining the phase angle between the load current and the output voltage, and judging whether the output current is zero or includes DC component. As a result, this method presents high precision.

Abstract: An integrated converter is provided. The integrated converter includes an AC/DC converter electrically connected to a three-phase power supply for converting an alternating current into a first direct current and achieving the object of the power factor correction; and a DC/DC converter electrically connected to the AC/DC converter for converting the first direct current into a second direct current, wherein while the AC power supply is electricity-drop, the controlling switch is turned on by the integrated converter and the integrated converter is switched from an AC/DC working mode to a DC/DC working mode, and while the AC power supply is restored to normal, the controlling switch is turned off by the integrated converter and the integrated converter is switched from said DC/DC working mode to the AC/DC working mode.

Abstract: A DC-to-DC converter. The converter has three inductors, two capacitors, a first switch and a second switch, a first rectifier and a second rectifier, and a transformer with a primary winding and a secondary winding. The first switch and the second switch are turned on alternately according to a controlling signal, and a current may flow through the primary winding of the transformer, thereby transferring energy to the second winding. The first rectifier and the second rectifier operate according to the energy transferred from the primary winding to obtain a solid current through the third inductor, and a solid DC output voltage is output to the load.

Abstract: A parallel inverter system includes a plurality of inverters of an instantaneous voltage control type, an output bus, an active power bus, a phase bus, and controlling devices. The output bus is used for connecting outputs of said plurality of inverters to a load. The active power bus is connected to the plurality of inverters so as to provide an active power sharing reference. The phase bus is connected to the plurality of inverters so as to provide a system phase reference. And, controlling devices control sinusoidal wave references of inverters to have the same phase, the reactive power, and the active power responsive to the active power sharing reference and the system phase reference. The related methods are also discussed.

Abstract: This invention provides a magnetron high frequency device which includes: a filtering inductor coupled to a positive end of a direct current power supply and having a first end and a second end; a central tap transformer having a central tap end, a first end and a second end, said central tap end being connected to said second end of said filtering inductor; a filtering capacitor a first end of which is connected to said first end of said central tap transformer and a second end of which is connected to a negative end of said direct current power supply; a first switch which is connected in series to said second end of said central tap transformer and connected to said negative end of said direct current power supply; an in-series circuit having a second switch and a second capacitor and coupled to said central tap transformer; a rectifying device coupled to a secondary winding of said central tap transformer; and a magnetron coupled to said rectifying device, wherein, said first capacitor, said second capaci

Abstract: The invention relates to an apparatus and a method for detecting a current direction in a PWM converter or an inverter having one or more upper and lower arms, each of which consists of a switching device with an anti-parallel diode. The voltage across the switching device presents a different value and a polarity that depend on the direction of the current flowing through the switching device, wherein the current direction is acquired by sampling this voltage in the period of the trigger signal being on. In a case of small current, this sampled voltage value is relatively large to the flowing current magnitude and is easy to be distinguished. Furthermore, this invention presents a method for obtaining the phase angle between the load current and the output voltage, and judging whether the output current is zero or includes DC component. As a result, this method presents high precision.

Abstract: A DC-to-DC converter. The converter has three inductors, two capacitors, a first switch and a second switch, a first rectifier and a second rectifier, and a transformer with a primary winding and a secondary winding. The first switch and the second switch are turned on alternately according to a controlling signal, and a current may flow through the primary winding of the transformer, thereby transferring energy to the second winding. The first rectifier and the second rectifier operate according to the energy transferred from the primary winding to obtain a solid current through the third inductor, and a solid DC output voltage is output to the load.

Abstract: A control system operates with a PWM speed regulation of a sensorless BLDC motor with a plurality of windings. A hybrid method is present in the invention utilizing BEMF induced in stator windings to indicate the commutation instant and a falling edge detection method to override PWM chopping and commutation noises. The present invention achieves reliable sensorless rotor position detection with relative concise and low cost circuit as well as little software expense. The control device of the present invention includes a comparator for generating the BEMF zero crossing points (ZCP), and means for deriving rotor position information by detecting the falling edge (or rising edge for low-side chopping case) of the generated ZCPs.

Abstract: The invention relates to the compensation of dead time effect in electronic appliances such as inverters or converters having one or more legs with two complementary switches. The invented method mainly includes following steps providing an initial pulse width modulated (PWM) reference, providing a bias current and detecting the bias current crossing points, providing a dead time compensation signal which is adjusted responsive to the crossing points, and adding the dead time compensation signal to the PWM reference. Hence an adaptive compensation is accomplished independent of types of switching elements and load conditions. A high reliable circuit with low cost is further included as a preferred embodiment of bias current crossing points detection.

Abstract: A control system operates with a PWM speed regulation of a sensorless BLDC motor with a plurality of windings. A hybrid method is present in the invention utilizing BEMF induced in stator windings to indicate the commutation instant and a falling edge detection method to override PWM chopping and commutation noises. The present invention achieves reliable sensorless rotor position detection with relative concise and low cost circuit as well as little software expense. The control device of the present invention includes a comparator for generating the BEMF zero crossing points (ZCP), and means for deriving rotor position information by detecting the falling edge (or rising edge for low-side chopping case) of the generated ZCPs.

Abstract: A DC-to-DC converter and a method thereof is provided. The DC-to-DC converter includes a power supply for providing a first direct current, a first capacitor, a first switch assembly for converting the first direct current into a first alternating current, a transformer for converting the first alternating current to a second alternating current, a rectifying circuit for converting and rectifying the second alternating current to a second direct current, a filtering circuit, and a range winding assembly for adjusting the output voltage of the second direct current in response to the voltage drop of the first direct current.

Abstract: A DC-to-DC converter and a method thereof is provided. The DC-to-DC converter includes a power supply for providing a first direct current, a first capacitor, a first switch assembly for converting the first direct current into a first alternating current, a transformer for converting the first alternating current to a second alternating current, a rectifying circuit for converting and rectifying the second alternating current to a second direct current, a filtering circuit, and a range winding assembly for adjusting the output voltage of the second direct current in response to the voltage drop of the first direct current.