77results about How to "High input power factor" patented technology

A buck converter LED driver circuit is provided. The driver circuit includes a buck power stage, a rectified AC voltage source, a voltage waveform sampler, and a control circuit. The buck power stage includes at least one LED and provides a first signal directly proportional to the current through the LED. The rectified AC voltage source is coupled to the buck power stage for driving the buck power stage. The voltage waveform sampler is coupled to the rectified AC voltage source for providing a second signal directly proportional to the voltage provided by the rectified AC voltage source. The control circuit is coupled to the voltage waveform sampler and the buck power stage for turning on and turning off the buck power stage according to a comparison between the first signal and the second signal.

The invention discloses a switching power supply controller for constant current driving of an LED by primary side control, a method for the constant current driving of the LED and a switching power supply formed by using the switching power supply controller. The switching power supply controller comprises an oscillator circuit, an input alternating current average value calculating circuit, a conduction time control circuit, a logic control circuit and a driving circuit. The controller controls the constant current driving of the LED by using a primary side control method to realize same output current and high power factor under the condition with controlled silicon dimming and high-low voltage input; and transformer isolation is directly used, so that the safety performance of the circuits is improved, a peripheral circuit is simple, the circuit cost is reduced, and the PCB (printed circuit board) distribution space is very small in favor of product miniaturization.

The invention relates to a high power factor DCM Boost PFC converter comprising a main power circuit and a control circuit. The main power circuit comprises an input voltage source vin, an EMI filter, a diode rectification circuit RB, a Boost inductor Lb, a switch tube Qb, a diode Db, an output capacitor Co and a load RLd. The high power factor DCM Boost PFC converter is characterized in that the control circuit adopts an output signal which adopts duty ratio as changing rule to drive the switch tube Qb. Adopting the varying duty ratio control, the high power factor DCM Boost PFC converter can improve the PF value to about 1 in the AC input voltage range of 90-265 V, increase the inductance capacity, obviously decrease the inductive current ripple, obviously reduce the effective value of the inductive current and correspondingly reduce the effective value of the current of the switch tube, has high input power factor and small output voltage ripple and contains less input current harmonic waves. The conduction loss of the high power factor DCM Boost PFC converter is reduced, and the efficiency is improved.

A buck converter LED driver circuit is provided. The driver circuit includes a buck power stage, a rectified AC voltage source, a voltage waveform sampler, and a control circuit. The buck power stage includes at least one LED and provides a first signal directly proportional to the current through the LED. The rectified AC voltage source is coupled to the buck power stage for driving the buck power stage. The voltage waveform sampler is coupled to the rectified AC voltage source for providing a second signal directly proportional to the voltage provided by the rectified AC voltage source. The control circuit is coupled to the voltage waveform sampler and the buck power stage for turning on and turning off the buck power stage according to a comparison between the first signal and the second signal.

An inductive coupled power transmission circuit has a rotating transformer, including an AC voltage supply for feeding an AC voltage via a series capacitor into the primary winding of said rotating transformer and a load being coupled to the secondary winding of said rotating transformer. The AC voltage supply includes a line rectifier for receiving AC voltage from a power line and generating a DC voltage. This is fed into a DC / DC converter for converting the DC voltage from the line rectifier into a controlled intermediate DC voltage. An AC generator generates an AC voltage from the intermediate DC voltage and feeds this via a matching transformer into the primary winding of the rotating transformer. A measuring circuit measures voltages and / or currents within the AC voltage supply and a function generator estimates voltage and / or current values at the load based on the measured values and controls the DC / DC converter and / or the AC generator based on the estimated values.

A permanent magnet synchronous motor sliding-mode speed observer driven by a two-stage matrix converter comprises a motor model based on the sliding-mode observer, an S-shaped switch function, an angle calculation module and an angular speed calculation module. Ualpha and Ubeta, obtained through the voltage reconstitution method, of stator voltages in a two-phase static coordinate system of a permanent magnet synchronous motor and the two S-shaped switch function output values (see the specification) serve as the motor model input based on the sliding-mode observer, the stator actual current values including ialpha and ibeta are subtracted from the four motor model output stator current observing values (see the specification) based on the sliding-mode speed observer, the two difference values serve as the S-shaped switch function input, the difference values are processed through the permanent magnet synchronous motor sliding-mode speed observer, then the two counter EMF estimated values in the two-phase static coordinate system are output, the rotor position is obtained through the angle calculation module, and the angular speed is obtained through the angular speed calculation module.

The invention discloses a switching power supply controller for constant current driving of an LED by primary side control, a method for the constant current driving of the LED and a switching power supply control device formed by using the switching power supply controller. The switching power supply controller consists of an input dimming angle detection circuit, a multiplier, an on-signal control circuit, a zero-crossing detection circuit, a comparer, a trigger and a driving circuit. A circuit controls the constant current driving of the LED by using a primary side control method to realize same output current and high power factor under the condition with controlled silicon dimming and high-low voltage input; and transformer isolation is directly used, so that the safety performance of the circuit is improved, a peripheral circuit is simple, the circuit cost is reduced, and the PCB (printed circuit board) distribution space is very small in favor of product miniaturization.

A power supply samples a rectified AC-input waveform and a regulated output voltage and combines them to control an AC-to-DC converter. The operating frequency and / or pulse width modulation of a switched-mode power supply are in large part fixed by a highly filtered output feedback signal to maintain a desired output voltage. A sample taken from the AC-input rectifiers is used in another feedback control signal to drive the operating frequency and / or pulse width modulation slightly up and down as a function of the rise and fall of each rectified-waveform sinusoid. The power delivered to the output, and thus the power demand on the input rise and fall with the instantaneous voltage of the AC input sinusoid. So the power factor is controlled by drawing current in-step with the voltage waveform.

The invention relates to a three-phase-to-five-phase double-stage matrix converter based on a Z source, which belongs to the technical field of power electronic converters and aims to overcome the problems that the traditional five-phase voltage source inverter is large in size, low in input side power factor and limited in service life of a frequency converter and causes serious pollutions to power grid harmonic waves and the existing matrix type converter is low in voltage transmission ratio. The matrix converter provided by the invention comprises a double-stage matrix type converter and a Z source network, wherein the double-stage matrix type converter is composed of a rectifier stage circuit and an inverter stage circuit; the Z source network is connected in series between the rectifier stage circuit and the inverter stage circuit; one end of a first capacitor of the Z source network is connected with one end of a first inductor to serve as a first input end; the other end of the first inductor is connected with one end of a second capacitor to serve as a first output end; the other end of the second capacitor is connected with one end of a second inductor to serve as a second input end; and the other end of the second inductor is connected with the other end of the first capacitor to serve as a second output end. The matrix converter provided by the invention is suitable for driving a five-phase motor.

The invention discloses a digital monocyclic control method of a PFC converter. The method comprises the following steps: firstly, sampling an output voltage and an inductor current, adopting a digital signal processor so that an output voltage sampling value passes by a voltage PI adjusting ring while utilizing the synchronous sampling function of the digital signal processor to finish the peak value sampling of the inductor current so as to ensure the monocyclic control requirements; and then obtaining a PWM control signal of a power device by a digital monocyclic core control algorithm. The digital monocyclic control method can be adopted to effectively simplify the digital control structure of PFC, improves the real-time computational capability and the control effect of a system and overcomes the adverse influence of discrete parameters of devices, such as operational amplifiers, capacitors, and the like in a traditional monocyclic control resettable integrator. In addition, the system fully keeps the accordance between a sampling interface and traditional PFC while fully keeping the advantages such as precisely controlled precision, perfect communication capability, and the like of traditional digital control.

The invention relates to an off-line uninterrupted power supply device, particularly to an off-line uninterrupted power supply device which can output harmonic-shaped AC voltage and has power factor improvement function. The device mainly comprises an AC input coupled to an AC power supply, an AC output coupled to a load end, a DC power supply used for supplying DC voltage, a DC / DC conversion device with the input end coupled to the DC power supply and the output end coupled to a DC bus, a DC / AC conversion device with the input end coupled to the DC bus and the output end coupled to the AC output, and a control circuit; wherein the control circuit controls the uninterrupted power supply device to realize three working modes of supplying harmonic-shaped DC voltage when commercial power is cut off, charging the DC power when the commercial power is normal and charging the DC power supply when the DC bus has excess energy so as to recycle energy.

The invention discloses a control circuit for a three-phase high power factor rectifier, and belongs to the field of electrical control. The control circuit comprises an input high-frequency filter circuit, a three-phase input inductor, a three-phase rectifier circuit, a switch tube power circuit, an output rectifier filter circuit, a voltage-dividing detection circuit, an input current detection unit, a single cycle controller and a switch tube driving circuit. A three-phase high power factor can be rectified, high-precision stable output voltage can be obtained, and interference resistance is high.

AC-DC converter is provided which comprises an auxiliary winding 8c in a transformer 8, a voltage detector 21 for detecting a voltage VN appearing on auxiliary winding 8c of transformer 8 by on-off operation of a main switching element 9 in a DC-DC converter 10 to produce an output signal VCP1 when voltage VN on auxiliary winding 8c has a negative polarity, a waveform shaper 23 for generating chopping signals VRC from output signal VCP1 of voltage detector 21, and a PWM circuit 27 for comparing output voltage VRC from waveform shaper 23 and output voltage VCH from a boosting chopper 3 to supply drive signals VG1 to step-up switching element 5 in boosting chopper 3 when output voltage VRC from waveform shaper 23 exceeds output voltage VCH from boosting chopper 3. While controlling fluctuation in output voltage from boosting chopper with respect to fluctuation in AC input voltage, the converter can improve input power factor relative to AC voltage and also reduce consumption power during light load period.

A power converter includes an inverter circuit for superimposing a generated voltage on an AC input voltage, a diode bridge full-wave rectifying circuit connected to the inverter circuit, smoothing capacitors connected between DC output terminals of the rectifying circuit, short-circuit switches connected to the rectifying circuit, a rectification mode changing circuit connected to the rectifying circuit, a short-circuit switch control circuit for maintaining the short-circuit switches in an on state in a short-circuit phase range, a rectification mode control circuit for maintaining the rectification mode changing circuit in an off state in the short-circuit phase range and an inverter control circuit for PWM-controlling the inverter circuit so that an output voltage of the rectifying circuit follows a target output voltage when the rectification mode changing circuit is in the off state.

Apparatus and associated systems and methods may relate to a process for supplying unidirectional current to a load, controlling a reverse electromotive force (REMF), capturing inductive energy from the load, and supplying the captured inductive energy to the load. In an illustrative example, an operating cycle may include a sequence of operations. First, inductive energy captured from the load on a previous cycle may be supplied to the load. Second, energy may be supplied to the load from an external power source. Third, a REMF voltage may be substantially controlled upon disconnecting the power source from the load. Fourth, the load current may be brought to zero by capturing the inductive energy for use on a subsequent cycle. In some embodiments, a single power stage may supply a DC inductive load, or a pair of power stages may be operated to supply bidirectional current to an AC load.

The invention discloses a control device used for improving the PF value of a DCM Buck PFC converter. The control device comprises a main power circuit and a control circuit. The main power circuit comprises an input voltage source vin, an EMI filter, a diode rectifier circuit RB, a Buck inductor Lb, a switch tube Qb, a diode Db, an output capacitor Co and a load RLd. The control circuit comprises an output voltage feedback control circuit, an input voltage feedforward circuit, a second multiplier and a sawtooth wave comparing and switch tube drive circuit. Input voltage feedforward and output voltage feedback are introduced, so that the duty cycle of the converter changes according to a certain rule in a power frequency cycle, and the PF value is improved to close to 1 in the AC input voltage range between 90V and 264V. The control device provided by the invention has the advantages of small output voltage ripple, small switch tube conduction loss, reduced required diode stress and the like.

An inductive coupled power transmission circuit has a rotating transformer, including an AC voltage supply for feeding an AC voltage via a series capacitor into the primary winding of said rotating transformer and a load being coupled to the secondary winding of said rotating transformer. The AC voltage supply includes a line rectifier for receiving AC voltage from a power line and generating a DC voltage. This is fed into a DC / DC converter for converting the DC voltage from the line rectifier into a controlled intermediate DC voltage. An AC generator generates an AC voltage from the intermediate DC voltage and feeds this via a matching transformer into the primary winding of the rotating transformer. A measuring circuit measures voltages and / or currents within the AC voltage supply and a function generator estimates voltage and / or current values at the load based on the measured values and controls the DC / DC converter and / or the AC generator based on the estimated values.

A ballast for operating a compact fluorescent lamp includes a power factor correction circuit and an energy storage capacitor coupled to the output thereof. The power factor correction circuit is configured to draw current from an AC power source during substantially more than half of the cycle of the input AC voltage waveform; i.e., when operated such that full power is supplied to the lamp. Energy transfer elements in the power factor correction circuit extract energy from the AC power source via an input rectifier, even when the peak voltage of the AC voltage waveform is substantially lower than the voltage of the energy storage capacitor, and transfer the energy to the energy storage capacitor a sufficient number of times during for each cycle of the input AC voltage waveform (e.g., at least 500 times for each full cycle of a 60 Hz input AC voltage waveform for a lamp operated at a frequency of 30 kHz), such that the energy storage capacitor remains substantially fully charged during steady-state ballast operation. The power factor circuit additionally provides for improved dimming capability, specifically, dimming the discharge to low levels, while maintaining steady, non-flickering operation.

The invention discloses a permanent magnet motor controller used for an electrolytic capacitor-free motor drive system and a method. Harmonic currents are injected to the electrolytic capacitor-free motor drive system for three times, the input side power pulsating quantity of the electrolytic capacitor-free motor drive system is reduced, decoupling of an electrolytic capacitor-free motor drive system input side control objective and a motor side control objective is realized, the problem that original power of a system is unbalanced is solved, the electrolytic capacitor-free motor drive system can obtain a high input power factor approximate to 1, thereby effectively suppressing fluctuation of a bus capacitor voltage, reducing a fluctuation coefficient of a DC bus voltage, and providing conditions for high-performance operation of a motor; and repetitive control is introduced into a speed loop of vector control, a rotation speed loop of the motor is improved, and on this basis, an SVPWM modulation module is utilized to generate six paths of instructions to control motor operation, thereby effectively solving the problem of poor output accuracy under a bus voltage fluctuation working condition, and realizing rapid and stable output of the controller.

The invention discloses a high-power-factor direct-current current output light-emitting diode (LED) driving circuit with a low-energy-storage capacitor. The LED driving circuit is composed of a diode rectifying bridge (1), an active non-linear capacitor network (3) and a follow-up switch power converter (2). The output end of the diode rectifying bridge (1) supplies power to the active non-linear capacitor network (3). Output voltage of the active non-linear capacitor network (3) is formed by overlapping direct current voltage with alternating current voltage with twice of electric supply frequency. The output voltage of the active non-linear capacitor network (3) supplies power to the follow-up switch power converter (2). The active non-linear capacitor network (3) is composed of a lower-energy-storage capacitor and an active switch network. By means of the LED driving circuit, the low-capacitance capacitor (such as a thin film capacitor and a ceramic medium capacitor) can be utilized to finish the energy storage function.

The invention discloses a high-efficiency solar lighting system. A multicrystal silicon solar photovoltaic module array with a no-load output voltage of 60V provides electric energy. A solar charging controller is connected with the multicrystal silicon solar photovoltaic module array and is also connected with an intelligent power supply controller, the intelligent power supply controller is formed by a UPS (Uninterruptible Power Supply) switching controller based on the control of a single chip, a battery bank is connected between the solar charging controller and the intelligent power supply controller and consists of total 18 deeply circular sealed maintenance-free lead-acid accumulators with monomers of 36V, the other input end of the intelligent power supply controller is connected with a rectification voltage stabilizer connected into the mains supply, and the output end of the intelligent power supply controller is sequentially connected with an automatic dimmer and an LED lamp set. In the high-efficiency solar lighting system, 36V low-voltage direct current drives the LED lamp set without needing an immediate alternating-current and direct-current transformation process, thereby effectively avoiding the electric power consumption in the immediate alternating current and direct-current transformation process and reducing more than 60% of electric power consumption; an IC (Integrated Circuit) is controlled and driven by an optical sensing PWM (Pulse Width Modulator), and the brightness of the LED lamp can be automatically and suitably regulated according to environment illumination. The invention is mainly applied to places needing more lighting lamps and higher uniformly-distributed illuminating brightness, such as markets, hotels, schools, office buildings and the like, and also applied to household lighting systems.

An AC-DC converter that converts a rectified voltage of an AC power supply AC to a DC output voltage by switching ON and OFF a switching device and controls the switching device by using a command value for and a detected value of the DC output voltage as well as a detected value of a reactor current includes: a current sense resistor and a low-pass filter for detecting a rectified current; a proportional controller that multiplies the detected value of the rectified current by a prescribed gain; an output voltage command calculator such as a divider that calculates an output voltage command for the switching device on the basis of an output of the proportional controller; and a circuit that compares the output voltage command to a carrier signal in order to generate a gate signal for the switching device, wherein the prescribed gain is effectively adjusted on the basis of a difference signal between a command value for and a detected value of the DC output voltage.

The invention discloses a diesel locomotive rectification chopping phase power module. The module comprises a main circuit of a diesel shunting locomotive traction electric transmission system and a main circuit of the rectification chopping phase power module. The main circuit of the traction electric transmission system comprises a main power generator, the rectification chopping phase power module and a three-phase inverter module, and the three-phase inverter module and the rectification chopping phase power module share one direct-current bus. The rectification chopping phase power modulefurther comprises a traction motor. The rectification chopping phase power module comprises a set of single-phase rectification bridge arms and a chopping branch. The AC-DC conversion function of thediesel shunting locomotive traction electric transmission system is achieved through three rectification chopping phase power modules identical in structure. The rectification chopping phase power modules are in lap joint with the direct-current bus of the main circuit, the single-phase rectification bridge arms are combined to achieve the three-phase rectification function, and three chopping branches are connected in parallel to achieve the direct-current chopping function. The assembly space of a converter space is effectively used, the wiring structure is simplified, temperature increaseof the module is reduced, the power module works more stably and more safely, and the adaptability is better.

The invention relates to a high-power-factor soft-switching three-phase power-regulating power supply which comprises an AB-phase high-frequency filter circuit. The AB-phase high-frequency filter circuit is connected with an AB-phase high-frequency rectifier circuit via an AB-phase rectifier circuit, an AB-phase inverter circuit and an AB-phase resonance circuit; a BC-phase high-frequency filter circuit is connected with a BC-phase high-frequency rectifier circuit via a BC-phase rectifier circuit, a BC-phase inverter circuit and a BC-phase resonance circuit; a CA-phase high-frequency filter circuit is connected with a CA-phase high-frequency rectifier circuit via a CA-phase rectifier circuit, a CA-phase inverter circuit and a CA-phase resonance circuit; a control circuit is connected with the output end of an output voltage and current detection circuit, an inverter current detection circuit and a power setting signal; and the control circuit is connected with the control ends of the AB-phase inverter circuit, the BC-phase inverter circuit and the CA-phase inverter circuit via the output end of a drive circuit. The high-power-factor soft-switching three-phase power-regulating power supply has high power factor, an inverter bridge adopts the load resonant moving power control soft-switching technology, so that the switching loss is reduced, the overall efficiency is increased, and the power supply is safe and reliable.

The invention discloses a circuit structure allowing energy to flow bidirectionally. According to the circuit structure allowing the energy to flow bidirectionally, a switch tube part is formed by parallel connection of a switch tube and a diode. The circuit structure allowing the energy to flow bidirectionally comprises a DC / DC conversion part, a DC / AC conversion part and a filtering part, wherein the DC / DC conversion part is connected with a power supply and a first capacitor, the first capacitor is connected with the ground, the DC / AC conversion part is connected with the first capacitor and the filtering part, and the filtering part is connected with an output end. According to the circuit structure allowing the energy to flow bidirectionally, AC inversion can be conducted when the energy flows in the forward direction, DC chopping can be conducted when the energy flows in the reverse direction, quite high conversion efficiency is achieved, and quite high flexibility of circuit design is achieved.

The invention relates to a photovoltaic micro-inverter power generation system based on a multi-winding high-frequency magnetic coupling system. The photovoltaic micro-inverter power generation system comprises a grid-connected system, a plurality of photovoltaic cell panels and a control unit, wherein each photovoltaic cell panel is connected to a bus capacitor through a boost topology; each bus capacitor is connected with a primary side winding of a multi-winding transformer through an H bridge inverter circuit; a secondary side winding of the multi-winding transformer is connected with a back-to-back H bridge inverter circuit; the control unit is set to be in information interaction with the grid-connected system, so that the voltages of the multiple bus capacitors are balanced, the voltages of the direct-current bus capacitors are balanced and the power grid side input power factor is 1, and the back-to-back H bridge inverter circuit is controlled to output alternating current of power frequency. The photovoltaic micro-inverter power generation system is small in size, light in weight, low in cost and capable of independently controlling each photovoltaic cell panel to track largest power points, has remarkable economic benefits and thus is suitable for popularized application.

A non-electrolytic capacitor power converter and control method for driving system of permanent magnet synchronous motor are disclosed, An output positive electrode of the single-phase rectifier circuit is connected with an anode of the first diode, an output negative electrode is connected with a negative electrode of the first thin film capacitor, a second switch tube emitter, a second thin filmcapacitor negative electrode, an input negative electrode of the three-phase inverter circuit, and an emitter of the first switch tube is connected with an inductance terminal and a cathode of the first diode. A collector of the first switch tube and a positive electrode of the first thin film capacitor, second diode cathode connection, A collector of the second switch tube is connected to the other end of the inductor L, simultaneously connected to the anode of the second diode and the anode of the third diode, The cathode of the third diode is connected with the collector of the third switch tube, and the emitter of the third switch tube is connected with the cathode of the second film capacitor, and is connected with the input cathode of the three-phase inverter circuit, which can effectively solve the problems of serious DC bus voltage fluctuation and poor static and dynamic performance of the existing electrolytic capacitance motor drive system.

An illumination device includes one or more LED's and a power supply configured to convert energy from a commercial AC power source and drive said LED's. The power supply includes a rectifier circuit, a phase detection circuit receiving an output voltage from the rectifier circuit and a switching element. A circuit includes the one or more LED's, an inductive element and a diode, and is coupled on a first end to the rectifier circuit and coupled on a second end to ground through the switching element. A current sensor is positioned to detect a current flowing to the light-emitting diode. A control circuit is coupled to receive the detected current and the detected phase of the rectified output voltage, and further coupled to the switching element and configured to generate a PWM signal for driving the switching element at a frequency higher than a commercial AC frequency. The PWM signal has a pulse width determined in accordance with one or more of a feedback control based on a current detected by the current sensor and a feed-forward control based on a phase of the pulsating voltage detected by the phase detection circuit.

The invention discloses a single-stage step-up inverter, which comprises an input rectification circuit, a pi-type circuit and an inverter circuit, wherein the input rectification circuit is connected with external AC; the pi-type circuit is connected with the input rectification circuit and the inverter circuit, and the inverter circuit is connected with an external load; the pi-type circuit comprises a first capacitor, a second capacitor and an inductor; the first capacitor and the second capacitor are in parallel connection; the inductor is connected onto a parallel loop of the first capacitor and the second capacitor; the first capacitor is in parallel connection with the input rectification circuit; the second capacitor is in parallel connection with the inverter circuit; the input rectification circuit is used for rectifying the external AC into DC pulsating voltage; when the DC pulsating voltage is higher than a voltage limit value, the pi-type circuit is used for DC filter; and when the DC pulsating voltage is lower than the voltage limit value, part of or all of bridge arms in the inverter circuit are adjusted to be in a shoot-through state, and the inductor in the pi-type circuit is charged, and after the shoot-through state is over, inductive voltage generated by the inductor is overlapped with the DC pulsating voltage and then outputted to the inverter circuit.

A harmonic-suppressing AC / DC power converter employs a control method for permitting the AC / DC power converter only to detect an input AC current and an output DC voltage. The control method can control the AC side of the AC / DC power converter to generate a voltage which is proportional to the input AC current. Thereby, the AC / DC power converter acts as a virtual resistor having a linear resistance characteristic. Accordingly, the input AC current of the AC / DC power converter can be controlled to approximate nearly as a sinusoidal wave with the performance of high input power factor and low input harmonic current.