Abstract:
A resonant converter and voltage stabilizing method thereof are provided. The resonant converter includes a converting stage circuit, a diode-rectifying stage circuit, a filter and load stage circuit, a logic circuit, a driving circuit, and an energy-recycling circuit. The method includes steps of recycling an energy from the filter and load stage circuit to the converting stage circuit when the resonant converter is light- or zero-loaded.
Abstract:
A resonance converter and a synchronous rectification driving method thereof are provided. The resonance converter includes a switch circuit having at least two first switches, a resonance circuit having a resonance frequency, a transformer, and a full-wave rectification circuit having two second switches each of which has a drain and a source and generates a channel resistance voltage when a current flows through the drain and the source. The synchronous rectification driving method includes steps as follow. When an operating frequency of the resonance converter is less than the resonance frequency and the resonance converter is coupled to a heavy load, the channel resistance voltage is compared with a reference voltage for driving the second switches of the full-wave rectification circuit; and when the operating frequency of the resonance converter is not smaller than the resonance frequency, duplicated signals of signals used to drive the first switches are respectively used to drive the second switches of the full-wave rectification circuit.
Abstract:
An uninterruptible power supply module is provided. The uninterruptible power supply module comprises an input terminal, a direct-current voltage source, a control module, a control arm-bridge module, an inductive element, a power source selection switch, and a switch element. The switch element is turned on before the power source selection switch is connected to the inductive element so that the direct-current voltage supplied by the direct-current voltage source is modulated by the control arm-bridge module to generate an output alternating current voltage to the load. And the switch element is turned off, i.e. not conducting electricity, after the power source selection switch is connected to the inductive element and the direct-current voltage source. Thereby, the use life of the power source selection switch element and the reliability of the uninterruptible power supply module are both increased.
Abstract:
A control apparatus for an induction motor is provided and includes a rotating-speed locked loop and a feed-forward magnetizing-axis angular position emulator. The rotating-speed locked loop emulates a speed control loop of the induction motor for producing an emulated torque current and an emulated rotor angular speed. The feed-forward magnetizing-axis angular position emulator receives the emulated torque current and the emulated rotor angular speed for producing a feed-forward estimated magnetizing-axis angular position, wherein according to the feed-forward estimated magnetizing-axis angular position, a first voltage controlling the induction motor is transformed from a synchronous reference coordinate system of the induction motor to a static reference coordinate system of the induction motor, and a two-phase current detected from the induction motor is transformed from the static reference coordinate system to the synchronous reference coordinate system. The state the stator angular frequency is at zero can be skipped through the apparatus.
Abstract:
An integrated converter having three-phase power factor correction is provided. The integrated converter includes two PFC circuits. Two DC/DC converters are controlled and switched by the integrated converter in accordance with a three-phase AC power source so as to convert the AC power source into a DC power source. The use of the elements in the integrated converter is efficient.
Abstract:
The present invention provides a three-level ac generating circuit and the control method thereof. The three-level ac generating circuit includes a three-level boosting circuit connected to an input source and including a positive boosting portion and a negative boosting portion; and a three-level inverting circuit connected to the three-level boosting circuit and including a positive inverting portion and a negative inverting portion, wherein while the input source is a relative low voltage, the relatively low voltage is boosted via the three-level boosting circuit, inverted and output via the three-level inverting circuit; while the input source is a relatively high voltage, the relatively high voltage is inverted and output via the three-level inverting circuit and wherein the output of the three-level ac generating circuit is power grid.
Abstract:
A resonance converter and a synchronous rectification driving method thereof are provided. The resonance converter includes a switch circuit having at least two first switches, a resonance circuit having a resonance frequency, a transformer, and a full-wave rectification circuit having two second switches each of which has a drain and a source and generates a channel resistance voltage when a current flows through the drain and the source. The synchronous rectification driving method includes steps as follow. When an operating frequency of the resonance converter is less than the resonance frequency and the resonance converter is coupled to a heavy load, the channel resistance voltage is compared with a reference voltage for driving the second switches of the full-wave rectification circuit; and when the operating frequency of the resonance converter is not smaller than the resonance frequency, duplicated signals of signals used to drive the first switches are respectively used to drive the second switches of the full-wave rectification circuit.
Abstract:
Parallel inverters without any communication buses and the controlling method thereof are provided. The parallel inverters are controlled by an instant voltage. Each inverter includes an output voltage waveform controller and a load-sharing controller. The output voltage waveform controller is connected to an output terminal of the inverter to control the waveform of an output voltage of the inverter. The load-sharing controller is connected to the output voltage waveform controller to control the load-sharing of the inverter and to make each inverter have the same phase, active power and reactive power without communications.
Abstract:
A method for testing a motor having a rotor and a winding is provided. The method includes steps of (a) providing a power to rotate the rotor to a predetermined speed, (b) removing the power, (c) measuring a terminal voltage of the winding while a current within the winding is zero, (d) obtaining a back electromotive force in the winding by compensating the terminal voltage with a performance of the rotor, (e) selecting a characteristic of the back electromotive force and (f) determining a magnetization of the motor by comparing the characteristic with a predetermined parameter.
Abstract:
An improved electronic ballast for providing an electrical energy to a fluorescent lamp circuit is provided. It includes a pre-heating inductor; a first resonant circuit connected to the pre-heating inductor in parallel and coupled to the fluorescent lamp circuit for pre-heating the fluorescent lamp circuit according to a first resonant frequency; a second resonant circuit coupled to the fluorescent lamp circuit for igniting the fluorescent lamp circuit according to a second resonant frequency; and a driving circuit coupled to the second resonant circuit for continuously providing the electrical energy to the first resonant circuit and the second resonant circuit respectively according to the first resonant frequency and the second resonant frequency.