Abstract:
Provided is a flux regulation method for use in a power converter, wherein the method is carried out by a flux bias controller. The flux bias controller includes a current detector which is configured to detect the primary current of the transformer of the power converter in a predetermined switching cycle, a DC bias processor which is configured to obtain the duty ratio control signal according to the sampled primary current outputted from the current detector for a switching cycle later than the predetermined switching cycle, and a PWM controller which is configured to generate driving signals to control the on/off operations of the switching circuit of the power converter according to the duty ratio control signal, thereby suppressing the DC bias of the transformer by regulating the duty ratio of the switch circuit.
Abstract:
The configurations of a parallel-connected UPS circuit are provided in the present invention. The proposed circuit includes a neutral, a battery having a positive and a negative terminals, and a plurality of PFC boost converters, each of which includes a PFC circuit including an inductor having a first terminal coupled to the positive terminal and a second terminal, a rectifying bridge coupled to the second terminal of the inductor, and having a first terminal and a second terminal coupled to the negative terminal, a switch bridge having a first terminal coupled to the first terminal of the rectifying bridge and a second terminal coupled to the second terminal of the rectifying bridge, and a control switch having a first terminal and a second terminal coupled to the neutral.
Abstract:
Provided is an uninterruptible power supply for providing a sinusoidal-wave output AC voltage. The uninterruptible power supply is advantageous in terms of a DC/DC converter unit consisted of a plurality of DC/DC converter, in which the input terminals of the DC/DC converters are connected in parallel with each other and the output terminals of the DC/DC converters are connected in series with each other. The output DC voltages of the DC/DC converters are configured to sum up to form a full-wave rectified DC voltage, which can be converted into a sinusoidal-wave output AC voltage by an inverter. Furthermore, the uninterruptible power supply provides an energy recycle converter configured for recycling the redundant energy of the uninterruptible power supply to charge a battery pack.
Abstract:
The configurations of a switched-mode power supply and a controlling method thereof are provided. The proposed switched-mode power supply includes a first output converter receiving a DC input voltage and generating a first high power DC voltage output and at least one low power DC voltage output, and a second output converter receiving the DC input voltage and generating a second high power DC voltage output coupled to the first high power DC voltage output to generate a coupled output, wherein the first output converter works and the second output converter idles when a transient power of the coupled output is not larger than a rated output power of the first high power DC voltage output, and both the first and the second output converters work when the transient power is larger than the rated output power.
Abstract:
Provided is an uninterruptible power supply for providing a sinusoidal-wave output AC voltage. The uninterruptible power supply is advantageous in terms of a DC/DC converter unit consisted of a plurality of DC/DC converter, in which the input terminals of the DC/DC converters are connected in parallel with each other and the output terminals of the DC/DC converters are connected in series with each other. The output DC voltages of the DC/DC converters are configured to sum up to form a full-wave rectified DC voltage, which can be converted into a sinusoidal-wave output AC voltage by an inverter. Furthermore, the uninterruptible power supply provides an energy recycle converter configured for recycling the redundant energy of the uninterruptible power supply to charge a battery pack.
Abstract:
A method for starting-up a motor having multiple stator windings and a rotor contains first providing current to two of the windings to excite a predefined phase and allowing one of the windings floating, Then, the back electromotive force (BEMF) induced in the floating winding is monitored. If a zero crossing of BEMF occurs in the floating winding within the maximum startup time, then it commutates to the next phase, which is adjacent to the first initial phase in the predetermined sequence of excitation phases. If no zero crossing of BEMF occurs in the floating winding within the maximum startup time, then it commutates to the next phase, which is functionally shifted by two phase-intervals from the predefined phase.
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:
The present invention relates to a method adopting square voltage waveform for driving a flat lamp used as the light source of a flat panel display or a common light fixture, the method comprising steps of: using a power unit to convert direct current into voltage of square waveform; using a voltage booster to raise the crest of the square voltage waveform to a specific trigger voltage capable of turning on the flat lamp; and providing a pulse-type current while enabling the pulse-type current to be just larger enough to break the dielectric barrier of the flat lamp.
Abstract:
The methods for starting a Hall-less single-phase BLDCM having an asymmetrical air gap are proposed. The provided methods are employed to input a specific amount of current impulse and stop the current impulse at a specific time such that the rotor of the single-phase BLDCM having an asymmetrical air gap can be realized to rotate in the pre-determined direction through one of the cogging torque and the rotor inertia after that specific time so as to accomplish the normal starting of a motor without the Hall-effect sensor.
Abstract:
The provided method and control circuit are employed to alternately control the dual boost PFC circuits. The control circuit for alternately controlling parallel-connected first and second boost circuits of a dual boost PFC circuit to achieve a current-sharing of the first and the second boost circuits includes: a first control circuit having a first current control loop for employing an output voltage of the PFC circuit, a feed-forward voltage, and an input reference voltage to generate a current reference, and sending the current reference to an input terminal of the first current control loop to generate a first PWM signal to drive the first boost circuit, and a second control circuit having a second current control loop for receiving the current reference through an input terminal of the second current control loop to generate a second PWM signal to drive the second boost circuit.