1430 results about "Power factor correction circuits" patented technology

An electrosurgical generator which provides a constant power output particularly suited for cutting arc formation at an active electrode which exhibits a dynamic active surface area of varying geometry. Essentially constant power-based control is achieved through the utilization of a d.c. link voltage the level of which functions to establish the amplitude of the output of an RF resonant inverter. A dual loop feedback control is described wherein output power based control signals are slowly introduced at low gain, while link voltage based controls are comparatively rapidly applied. Enhanced development of a controlling d.c. link voltage is achieved through the utilization of an input network incorporating a power factor correction stage.

A single phase power supply module for electric arc welders and plasma arc cutters comprising: a single phase input stage; positive and negative output terminals; a full wave rectifier connected to the input stage for rectifying the single phase voltage at the input stage; a buck converter type power factor correcting circuit for controlling current flow from the input stage to the rectifier, which buck converter has an output capacitor regulated to an intermediate voltage in the range of 100-150 volts; and, a high speed DC to DC converter having an internal transformer coupling applying voltage across the output terminals and means for regulating the applied voltage to an output voltage in the range of 0-113 volts. The module is universal and several can be connected in parallel, in series or to switch networks to construct several welders or cutters.

A combined power supply and driver control module includes rectifier circuitry, switching circuitry, and driver circuitry for providing output power to a load. Rectified output from an input power source is used to produce a DC power. The switching circuitry receives the DC power and modulates the input current drawn from the power source. An intelligent control module includes control circuitry, such as a digital processor, for controlling the switching circuitry. Power factor is improved by modulating the input current to be closer in phase with the voltage of the power source. Also disclosed is a power factor correction circuit in which a digital processor reads waveform values from a lookup table and modulates the input current waveform based on the values. A zero crossing detector connected to the input power source may direct the digital processor when to commence reading values from the lookup table.

A controller for use with a current-controlled frequency-modulated power factor corrector having a power switch therein, and a method of regulating the same. In one embodiment, the controller includes a sensing circuit configured to detect a sense current that is representative of an input current to the power factor corrector. The controller also includes a frequency modulation circuit, coupled to the sensing circuit, configured to provide a signal that causes at least one of: (a) an increase of a switching frequency of the power switch when the input current increases, and (b) a decrease of the switching frequency of the power switch when the input current decreases.

The present invention relates to an electronic ballast that energizes fluorescent lamps connected in a parallel configuration. The ballast employs a power factor correcting boost converter that can be used over a wide range of AC line voltages to provide regulated power to a self-oscillating sine wave inverter that drives the fluorescent lighting load at high frequencies. The inverter employs special networks that limit a certain type of shoot-through current, and thus improve the efficiency of the unit. Also included is a restart circuit that limits power losses during the zero lamp condition, by periodically interrupting the inverter operation when the zero lamp state is detected. To improve operation of the power factor correcting circuitry over the wide range of AC line voltages, a DC offset is added to the sampled AC voltage at the higher AC line voltages by Zener diode based coupling circuit.

The present invention relates to a set protection circuit for when a diode short-circuit defect occurs in a power factor correction circuit of a critical conduction mode. In a conventional power factor correction circuit, an excessive amount of current flows to a switch if a diode is short-circuited so that the switch is damaged. In order to prevent damage to the switch, the present invention provides a method for stopping turn-on of the switch when a switch current is excessive.

A power factor correction circuit utilizes a digital controller string comprised of an analog-to-digital converter, which is input to a digital compensator followed by a pulse width modulation circuit for generating a switching pulse. The loop current in a regulator circuit such as a boost regulator is sensed and input to one side of a differential analog-to-digital converter, the other side thereof providing a digital reference current. This digital reference current is derived from comparing the input AC voltage to the regulator with the DC output voltage and processing these two voltages with a PFC algorithm to provide this reference voltage.

Light load efficiency of a power factor correction circuit is improved by adaptive on-time control and providing for selection between a continuous conduction mode and a discontinuous conduction mode wherein the discontinuous conduction mode increases time between switching pulses controlling connection of a cyclically varying voltage to a filter/inductor that delivers a desired DC voltage and thus can greatly reduce the switching frequency at light loads where switching frequency related losses dominate efficiency. The mode for controlling switching is preferably selected for each switching pulse within a half cycle of the cyclically varying input voltage. A multi-phase embodiment allows cancellation of EMI noise at harmonics of the switching frequency and adaptive change of phase angle allows for cancellation of dominant higher order harmonics as switching frequency is reduced.

A power inverter control adjusts input power to track with output power to reduce energy handling requirements for an inverter DC bus. Input power to the power inverter circuit is measured and compared with a measurement of inverter output power. The comparison result is applied to a power factor correction circuit to adjust input power to track with output power, while obtaining a good power factor for the power inverter circuit. The energy requirements and ripple voltages or ripple currents on the DC bus are reduced, leading to a reduction in rating specifications for passive energy storage elements on the DC bus.

The present invention relates to a power factor correction circuit that can reduce distortion of input current in a switching mode power supply. The power factor correction circuit provided in the present invention basically comprises a first inductor which is electrically connected at a first end thereof to an input terminal, a second coil that is coupled to the first inductor to form an induced voltage, a switch electrically connected to the a second terminal of the first inductor, and a switching control unit for controlling turn-on and turn-off of the switch. In such a power factor correction circuit of the present invention, the switching control unit is configured to differently set a turn-on period of the switch depending on the input voltage by generating a signal for controlling the turn-off of the switch using a second coil voltage induced at the secondary coil of the inductor by input voltage or a directly sensed input voltage. Accordingly, distortion of input current can be effectively corrected.

The invention discloses an integrated circuit of a vehicle-mounted charger and a DCDC. The integrated circuit comprises a power factor correction side circuit connected with a power factor correction circuit, a high-voltage battery side circuit connected with a high-voltage battery circuit, a low-voltage battery side circuit connected with a low-voltage battery circuit, and a transformer T1 coupled with the three circuits. The integrated circuit integrates the vehicle-mounted charger and a high-power DCDC module which are independent, shares a power switching tube and a control circuit, shares a magnetic core for energy delivery, can flexibly realize control and switching of a charger mode, a DCDC mode and an inversion mode, and is concise and ingenious in design, small in size, light in weight and low in cost.

The configurations of a three-phase buck-boost power factor correction (PFC) circuit and a controlling method thereof are provided in the present invention. The proposed circuit includes a first single-phase buck-boost PFC circuit receiving a first phase voltage and having a first and a second output terminals and a neutral-point for outputting a first and a second output voltages, a second single-phase buck-boost PFC circuit receiving a second phase voltage and coupled to the first and the second output terminals and the neutral-point, a third single-phase buck-boost PFC circuit receiving a third phase voltage and coupled to the first and the second output terminals and the neutral-point, a first and a second output capacitors coupled to the first and the second output terminals respectively, and to the neutral-point also and a neutral line coupled to the neutral-point.

A power factor correction circuit includes a first rectifier to rectify an AC voltage, a series circuit connected to an output of the first rectifier and including a step-up reactor and a switching element, a rectifying-smoothing circuit connected to both ends of the switching element and including a second rectifier and a smoothing capacitor, an input voltage detector to detect an output voltage of the first rectifier, an output voltage detector to detect a voltage across the smoothing capacitor, an error amplifier to amplify an error between the output voltage signal and a reference voltage, and a controller to determine an ON/OFF duty ratio of the switching element according to the amplified error signal and a result of a calculation carried out on the input voltage signal and output voltage signal.

The invention discloses an adaptive control method of a power factor. The adaptive control method comprises the following steps of: generating three voltage reference values by calculating, multiplying the three voltage reference values, taking a product of the three voltage reference values as a current reference value, comparing the current reference value with a direct current bus current, and outputting a calculation result after carrying out current error compensation processing; determining a duty ratio by virtue of the calculation result to form a pulse signal, controlling the make-break operation of a chopper to carry out chopping processing on a direct current voltage rectified and output by a rectifier bridge, generating a smooth direct current bus current and an alternating current input current in a same phase with an alternating current input voltage, improving the power factor, and reducing the current harmonic distortion ratio. A power factor correction method, provided by the invention, can be used for realizing the adaptive control on alternating current power supplies in different frequencies. The adaptive control method of the power factor is applied into variable frequency air conditioner products, and can be suitable for air conditioners based on inputs of 50-Hz and 60-Hz alternating current power supplies; and according to the adaptive control method of the power factor, a design purpose that a development is suitable for multiple types of machines is really achieved, the development period is shortened, and the research and development costs are lowered.

The invention discloses a bridgeless power factor circuit correcting circuit system used for critical conduction mode and a control method thereof. The bridgeless power factor circuit correcting circuit system comprises a bridgeless power factor correcting circuit, a first auxiliary winding and a second auxiliary winding, wherein the bridgeless power factor correcting circuit comprises a first switch, a first inductance and a second inductance; the first auxiliary winding is coupled to the first inductance and produces a first sensing signal; the second auxiliary winding is coupled to the second inductance and produces a second sensing signal, the first sensing signal and the second sensing signal are used for producing an inductance current detection signal; meanwhile, when the value of the inductance current detection signal is zero, the first switch is connected.

A high efficiency power drive device enabling serial connection of LED lamps thereto, which includes a power source filter circuit, an AC to DC rectifier, a power factor correction circuit and an LED constant current drive circuit. The power factor correction circuit is utilized using the so-called transition mode technique to obtain voltage required by the LED lamps when serially connected, and current control is used to achieve a state whereby the current and voltage are in the same phase. A current control IC and an externally set resistor are further used to eliminate the need to adopt any CPU (central processing unit) while accurately directly controlling the output pulse width of PWM (Pulse Width Modulation).

The configurations of a single-phase dual buck-boost/buck power factor correction (PFC) circuit and a controlling method thereof are provided in the present invention. The proposed circuit includes a single-phase three-level buck-boost PFC circuit receiving an input voltage and having a first output terminal, a neutral-point and a second output terminal for outputting a first and a second output voltages, a single-phase three-level buck PFC circuit receiving the input voltage and coupled to the first output terminal, the neutral-point and the second output terminal, a first output capacitor coupled to the first output terminal and the neutral-point, a second output capacitor coupled to the neutral-point and the second output terminal, and a neutral line coupled to the neutral-point.