113results about How to "Reduce power factor" patented technology

A programmable LED constant current driver circuit for driving LEDs at constant current and dimming the LEDs using standard, off-the-shelf dimmers is provided. The current driver circuit of the present disclosure includes a temperature compensation feature which controls the on time for the LEDs based on a measured temperature of the current driver and associated circuits. In another embodiment, the current driver circuit is designed to receive a 24 VAC input and drive one or more LEDs in a transformer-based system dimming system.

A power conversion apparatus includes two power conversion circuits, two direct-current inductors, and a pulse-width-modulation control circuit. One of the two power conversion circuits is connected in parallel to a direct-current load or a single-phase alternating-current load, and the other of the two power conversion circuits is connected in parallel to a three-phase alternating-current load. The two power conversion circuits are connected in reverse polarity to each other via the two direct-current inductors. The pulse-width-modulation control circuit pulse-width-modulates the two power conversion circuits, allows switching between the two power conversion circuits, and realizes a bidirectional step-up / down operation between the direct-current load or single-phase alternating-current load and the three-phase alternating-current load.

The invention discloses a correction device for power factor of variable-frequency air conditioner with a converter to change ac power from input port into dc power and a frequency converter to change dc power from said converter into three-phase ac power with need working frequency, which comprises: a zero-crossing detection circuit connected to input port of power, a control part connected with said circuit to determine electrical degree angle based on detection result and then output opposite control signal, a current regulation circuit connected with said control part and converter to regulate current waveform of ac power and improve current harmonic.

The disclosure discloses an electric energy conversion device and system, to solve the problems of severe harmonic pollution, low power factor during the electric energy feedback from a power generation device to a power grid in the conventional art. The electric energy conversion device comprises: a plurality of single-phase rectifier bridge circuits, a first input ends of the a plurality of single-phase rectifier bridge circuits, and a second input ends of the a plurality of single-phase rectifier bridge circuits, wherein two input ends of each three-phase fully-controlled bridge circuit are connected with two output ends of each the rectifier bridge circuit respectively. Through the technical solution of the disclosure, the waveform coefficient of the current of the power generation device is improved, the harmonic wave is reduced, and the power factor is improved.

The invention provides a centralized power supply system for LED illumination in a large area and a driving method of the centralized power supply system. Aiming at the design of an LED illumination system in the range of the large area, LED lamps are distributed according to actual demands and form a plurality of branches through appropriate series-parallel connection, and driving and control devices are concentrated in one place to be convenient for management and maintenance. Three-phase power-frequency alternating current is used as an input power supply, an AC-DC matrix converter is applied to a high-power LED illumination driving system, and an electrolytic capacitor is removed, so that the working life of the driver is prolonged, and meanwhile three-phase sinusoidal input current and unity power factors can be obtained. The output side of the AC-DC matrix converter provides an isolated constant current power supply for each LED branch through double-tube forward converters. The forward converters share a bridge arm, and the number of switching tubes is reduced. The modulation of the AC-DC matrix converter and the double-tube forward converters is realized through microprocessing chips, and the constant current control of the LED branches is realized.

The invention relates to a power unit with brake function for a unit cascaded high-voltage frequency converter, which belongs to the technical field of power electronic equipment. The invention aims at providing the power unit of the cascaded high-voltage frequency converter, which has small feedback energy and can be used under the occasions which require rapid brake and startup. The adopted technical scheme is as follows: the power unit with the brake function for the unit cascaded high-voltage frequency converter comprises the power unit and a brake unit, the power unit comprises a short-circuit protection circuit, a bridge rectifier circuit, a direct current filter circuit, an inverter circuit and a controller of the power unit which are connected in sequence, wherein the short-circuit protection circuit is connected with the rectifier circuit, the rectifier circuit, the direct current filter circuit and the inverter circuit are connected in parallel, the inverter circuit is further connected with a control circuit of the power unit, the brake unit is connected in the power unit in parallel, and the brake unit consists of an energy consumption brake circuit and a brake controller, thereby being widely applied in various types of high-voltage frequency converters.

The invention discloses a flyback switching power circuit. A valley filling circuit is adopted in a filter circuit of the flyback switching power circuit. The work voltage of a capacitor C1 and the work voltage of a capacitor C2 in the valley filling circuit are reduced by a half, -40 DEG C electrolytic capacitor can be adopted, and a third capacitor C3 is in parallel connection to a charging diode D3 in an existing valley filling circuit, so that the withstand voltage of the third capacitor C3 is half of a peak value of input pulse direct current, and high-frequency ripple current of a back switching power 300 can be fully and effectively absorbed. A varistor RV1 and a varistor RV2 are arranged before and behind a rectifier bridge 101, and a thermistor NTC, a safety capacitor X1 and an inductor L form a multi-level two-way filter and protection circuit. The flyback switching power circuit has the advantages that the power factor is high and not affected by a value of the C3, the topological structure of the circuit is simple, the absorption effect on surging voltages is good, cost is low, the size is small, and the difference mode conduction interference degree of the flyback switching power circuit reaches the CLASS B in GB9254.

A constant-current-drive LED module device includes a rectifier configured to receive and rectify an alternating current power source; a unidirectional LED module unit configured to connect to one end of the rectifier; and a constant current unit configured to connect between the unidirectional LED module unit and the other end of the rectifier to control constant current.

A non-contact power supply device comprises: a primary winding (101); and a secondary winding (201) to which an electric power is supplied from an alternating current power supply via the primary winding, wherein an impedance characteristic of Z1 with respect to a frequency is such that a minimal value is provided in the proximity of a frequency of a fundamental wave component of the alternating current power supply and another impedance characteristic of Z2 with respect to the frequency is such that the frequency of the fundamental wave component is provided between the frequency which is nearest to the frequency of the fundamental wave component and at which a maximal value is provided and the frequency which is nearest to the frequency of the fundamental wave component and at which the minimal value is provided.

The invention discloses a three-grade low-voltage power distribution network voltage control device and a control method thereof. The device comprises an integrated control system, a three-phase unbalance control device, a dynamic reactive compensating device and a line voltage adjusting device. The three-phase unbalance control device, the dynamic reactive compensating device and the line voltage adjusting device are successively connected in the line of the low-voltage power distribution network. The integrated control system performs coordinated unified control on each device, thereby performing voltage control on the low-voltage power distribution cabinet according to a three-step sequence of line voltage adjusting, three-phase unbalance control and dynamic reactive compensation. According to the control method of the three-grade low-voltage power distribution network voltage control device, first-step voltage adjustment, second-step three-phase unbalance control and third-step dynamic reactive compensation are successively performed according to data which are acquired by each device. The three-grade low-voltage power distribution network voltage control device can realize electric energy quality unified and comprehensive control on three-phase unbalance, low power factor, low end voltage, etc. Furthermore the three-grade low-voltage power distribution network voltage control device and the control method have advantages of simple control realization, high control effect, capability of suppressing resonance and preventing overregulation, etc.

When multiple motors (40) share a common DC power supply (10) via a bus (20), a system and method is provided for managing the effect of regenerative energy caused by a motor. The regenerative energy may be sensed, e.g., by a power electronics controller (50, 50′). In response, one or more of the other motors currently in operation may be controlled to operate according to a reduced power factor. Thus, the excess energy is consumed without adding any new components or increasing the amount of work performed in the system.

The invention discloses an adaptive direct torque control method for flux linkage of a non-salient pole type permanent magnet synchronous motor. The method comprises the following steps of: determining a quadrature axis component of a stator flux linkage required at a certain load torque according to motor torque observed by a torque observer; and synthesizing a rectangular axis component of the stator flux linkage to finally obtain a stator flux linkage reference in the direct torque control method by taking the flux linkage of the rotor permanent magnet as a direct axis component of the stator flux linkage by reducing direct axis current of the motor and improving a power factor angle, wherein the stator flux linkage reference adaptively changes along with the variation of the motor load torque; and high-power-factor running of the permanent magnet synchronous motor is realized while torque response rapidity is ensured.

A novel on-load-tap-changing combined rectifier auto-transformer with independent ends comprises a regulating transformer and two rectifier transformers. Phases of the regulating transformer are the same in structure. The regulating transformer comprises a high-tension coil, a front-end auto-regulating winding, a tail-end auto-regulating winding, a front-end on-load tap changer and a tail-end on-load tap changer. The front-end auto-regulating winding and the rear-end auto-regulating winding are combined ad connected to the front end of the high-tension coil of the regulating transformer and are connected with the same in parallel. The front-end and rear-end auto-regulating windings supply variable voltage to high-tension coils of the rectifier transformers through tap changing so as to achieve rough voltage regulating. The tail-end auto-regulating winding and the tail-end on-load tap changer are combined and connected to the tail ends of the high-tension coils of the rectifier transformers so as to achieve fine voltage regulating. The rough tap changer and the fine tap changer are fully isolated, regulating range is wide, regulating is multilevel, output of low voltage is smooth, operating performance is stable, harmonic wave generated by rectification can be reduced, power factor and production efficiency of rectifier systems are increased, and manufacturing cost is lowered.

The invention relates to a three-mode hybrid single-phase five-level rectifier. The three-mode hybrid single-phase five-level rectifier comprises an alternating current power supply Vs, an inductor L,switching tubes S1, S2 and S3, diodes D1-D10, capacitors C1 and C2 and a load RL. According to the three-mode hybrid single-phase five-level rectifier, the circuit topology of the rectifier needs a small number of switching tubes, so that the control difficulty of the topological structure of the rectifier and the design cost of the circuit of the rectifier are reduced to a certain extent, switching loss is reduced, and the working efficiency of the five-level rectifier is improved; and meanwhile, the passive rectification mode of a diode passive rectifier bridge can improve the reliability of the single-phase five-level rectifier, can guarantee the reliable external output of the five-level rectifier, and can guarantee the output even if a switching tube is in a damaged or fault state.

The invention relates to a power factor control analysis method for power transmission and distribution lines. The power factor control analysis method comprises the steps of collecting telemeasuring data through a power monitoring system, and calculating electric quantity through an electric energy calculation unit; determining a calculation model of power transmission and distribution line loss; performing data processing on the calculation model through an electric energy measuring apparatus to obtain a power factor of an assessment point, wherein the electric energy measuring apparatus performs data processing for one time at certain interval times; and checking the power factor of the assessment point. According to the power factor control analysis method, the power factor of the power transmission and distribution lines can be reasonably calculated and modified according to the structural characteristics of the power transmission and distribution lines; and the power factor of the assessment point can be improved and the system operation can be optimized by adopting hierarchical control and partitioning in-place balanced reactive balance adjustment means.

When multiple motors (40) share a common DC power supply (10) via a bus (20), a system and method is provided for managing the effect of regenerative energy caused by a motor. The regenerative energy may be sensed, e.g., by a power electronics controller (50, 50′). In response, one or more of the other motors currently in operation may be controlled to operate according to a reduced power factor. Thus, the excess energy is consumed without adding any new components or increasing the amount of work performed in the system.

The invention provides a high-power compensation type cascade diode H-bridge unit power factor rectifier which comprises various main power circuits which are formed by cascading a plurality of module units in a three-phase star connection, angle connection or double-star connection mode. Meanwhile, the invention further provides a small-capacity compensation device formed through serial connection or parallel connection or series-parallel connection, and unit power factor rectification can be easily achieved. The rectifier has the advantages that a low-voltage power switch tube can be used for large-power rectification conversion under high voltage, a power-frequency phase-shifting transformer which is large, heavy and complex in wiring does not need to be used, the topological structures of the main power circuits are simplified, the number of switching devices which are used is greatly reduced, loss of the circuits in work is reduced, work efficiency of a system is improved, the size is small, the weight is low and cost is low. Meanwhile, the power factor of the rectifier always keeps to be 1 on the situation that a load is changed. The rectifier has important application value in the application field such as high-voltage direct current transmission, high-power electric and electronic transformers, high-power medium-and-high-voltage AC-DC-AC converters.

The invention provides a current tracking control method. For a hybrid rectifier including a three-level PWM boost rectifier, the current tracking control method comprises the steps of obtaining three-phase given current, acquiring three-phase input real-time current of the hybrid rectifier, sorting three-phase input phase sequences of the hybrid rectifier according to three-phase set duty ratio from small to big, obtaining the breakover time Tx, Ty and Tz of a three-phase switch in a working period according to a circuit structure of the hybrid rectifier, judging whether 0<Tx<Ts / 2, 0<Ty<Ts / 2 or 0<Tz<Ts / 2 is established or not; correcting the Tx, Ty or Tz; obtaining the three-phase duty ratio of the three-phase switch; respectively performing breakover or turnoff of the corresponding three-phase control switch according to the three-phase duty ratio after pulse width modulation so as to achieve current tracking. The current tracking control method has the advantages of being high power factor, low in harmonic distortion rate and the like and can be widely applied to the field of current tracking control.

In some aspects of the invention, a zero current detecting circuit of a switching power supply device detects a gradient of the current flowing in an inductor in the OFF state of the switching element and detects the timing at which the current through the inductor becomes zero corresponding to the detected gradient of the inductor current. Specifically, the zero current detecting circuit receives a signal for controlling ON / OFF driving of the switching element and a voltage signal proportional to the current flowing through the inductor in an OFF state of the switching element. The voltage signal can be compared sequentially with first and second comparison reference voltages to control charging and discharging of a capacitor. Further, the zero current detecting circuit can detect a timing at which the charging and discharging voltage of the capacitor as the timing of zero current flowing through the inductor.

The present disclosure is directed to a gas turbine engine assembly having a compressor configured to increase pressure of incoming air, a combustion chamber, at least one turbine coupled to a generator, a torsional damper, and a controller. The combustion chamber is configured to receive a pressurized air stream from the compressor. Further, fuel is injected into the pressurized air in the combustion chamber and ignited so as to raise a temperature and energy level of the pressurized air. The turbine is operatively coupled to the combustion chamber so as to receive combustion products that flow from the combustion chamber. The generator is coupled to the turbine via a shaft. Thus, the torsional damper is configured to dampen torsional oscillations of the generator. Moreover, the controller is configured to provide additional damping control to the generator.

The invention relates to the field of power factor correction, in particular to management method and equipment for running passage numbers in a multi-phase staggered printed flexible circuit (PFC). By the management method and equipment, the technical problem how to improve a power factor under the condition that hardware cost is not increased is solved. The passage number management method proposed by the invention comprises the steps of firstly, acquiring a current output power of the multi-phase staggered PFC; secondly, acquiring a corresponding relation between the pre-determined output power and the running passage number; and finally, acquiring target numbers of running passages according to the current output power and the corresponding relation, and controlling PFC passages in target numbers to run. By the method, no extra power device is needed, and thus, the hardware cost cannot be increased; the output power of the PFC can be obtained by calculating the power of a load, thepassage numbers are controlled according to the current output power, and the power factor of the system can be effectively improved.

An intelligent mains power supply dimmer unit and LED lamp combination with improved power factor. The dimmer applies phase-cutting at a first angle for a first period to a mains voltage supplied to the lamp, whereafter the dimmer removes the phase-cutting. The lamp interprets the first angle as a first power level, which is then stored. The lamp retrieves the level after the first period and regulates its consumption accordingly.

Provided is an electronic ballast including: a rectifier which rectifies alternating current (AC) power into direct current (DC) power; a power factor compensator which improves a power face of the DC power; an inverter which inverts the DC current into high frequency square wave power; and a resonant circuit which receives the high frequency square wave power from the inverter, adjusts impedance, transforms the high frequency square wave power into high frequency sine wave power, and outputs the high frequency sine wave power.

A composite permanent magnet synchronous machine includes a permanent magnet synchronous machine module having a rotor unit and a stator unit; a bottom base having an accommodation space; a top cover having a front surface; and a shaft penetrating through the front surface. The rotor unit has P rotor magnets and the stator unit has S slots, wherein a tooth part is defined between every two adjacent slots, and a coil is wound on the tooth part, where P is 38N, S is 36N, and N is a positive integer; or P is 34M, S is 36M, and M is a positive integer. The machine is suitable for wind power generators or any other machine structure.

An AC light emitting device, a driving device thereof and a driving method are disclosed. The driving device includes a sub-driving part turned on corresponding to each of positive and negative voltage regions of an AC voltage source to provide current paths for operating at least two LEDs, and a free-charge part charging with a voltage to be supplied to one of the at least two LEDs which is not operated while the other LED is operated by the sub-driving part. The AC light emitting device, the driving device thereof and the driving method thereby can solve problems, such as a decrease in power factor, severe total harmonic distortion, excessive flickering, and the like, due to operating characteristics of the AC light emitting device by application of an AC voltage source thereto.

A single stage DAB control circuit for converting an unbalanced grid voltage into a DC voltage is provided. The control circuit includes a controller having a voltage detection module, a first transformation module, a level shift module, and a second transformation module. The voltage detection module provides voltage component values that are indicative of the voltage in each phase of a three-phase AC power supply. The first transformation module converts the voltage component values from a stationary reference frame into reference voltage signals in a rotating reference frame using a Clarke-Park transform. The level shift module compensates the reference voltage signals to simulate an ideal or balanced three-phase AC voltage. The second transformation module converts the compensated reference voltage signals from the rotating reference frame to the stationary reference frame using an inverse Clarke-Park transform. The controller is then operable to control operation of a single stage DAB converter for providing a DC charging voltage to a battery that is substantially free of fluctuations or ripple.

The invention discloses a charger system, and belongs to power electronic and power automatic equipment. The charger system is suitable for electric automobile charging occasions, and the problem of relatively low efficiency of the conventional two-stage charger equipment is solved. The charger system comprises a high-frequency rectifier, a high-frequency direct current transformer and a controller, wherein the high-frequency rectifier is connected with the high-frequency direct current transformer through a direct current bus; and the controller generates driving signals from one to six and sends the driving signals to the high-frequency rectifier, generates seventh and eighth driving signals and sends the seventh and eighth driving signals to the high-frequency direct current transformer, and comprises a sampling and conditioning module, a double-closed-loop control module, a first signal generation module and a second signal generation module. The charger system has the characteristics of high power factor and low current harmonic of the high-frequency rectifier and the characteristics of high efficiency and electrical isolation of the high-frequency direct current transformer, so that two working modes of constant current charging and constant voltage charging for an energy storage battery and a power battery are realized; and the charger system is suitable for charging systems of electric chargers.