89results about How to "Improve PF value" patented technology

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.

The invention relates to a three-state three-level PFC circuit, which comprises an inductor, a combined three-state switch, a first capacitor and a second capacitor. The inductor is connected between a first end of an AC power supply and a first end of the combined three-state switch; a second end of the combined three-state switch is connected at a first end of the first capacitor; a third end of the combined three-state switch is connected at a second end of the second capacitor; a fourth end of the combined three-state switch is grounded; and the first end of the first capacitor, a second end of the first capacitor, and the second end of the second capacitor output three-level voltage. The invention also provides a multi-state three-level PFC circuit correspondingly. Compared with the common circuit without a three-state switch or a multi-state switch, the PFC circuit provided by the invention can obviously reduce the dimensions of the inductor and the capacitors, improve the powerfactor of the circuit simultaneously and reduce the total harmonic content on the premise of maintaining the switch frequency and ripples on a passive device invariable, and can reduce the switch frequency and obviously improve the circuit efficiency on the premise of maintaining the input current ripple frequency and magnitude invariable.

The invention relates to a multi-purpose two-way power electric test power supply system and a control method thereof. The system comprises a PWM reversible rectifier and an active clamp two-way DC/DC converter. The method comprises the steps as follows: a single-polarity SPWM control is adopted at a first stage; a first stage circuit has a power factor correcting function when power flows forwardly, and a PF value is very high; when the power reversely flows, the total harmonic distortion is low; a phase shift control or a PWM control is adopted at a second stage; when the power flows forwardly, the adjustment range of output DC voltage is wide; and after an active clamp circuit is adopted, soft switching of a switch tube of a second stage circuit is achieved, so that the multi-purpose two-way power electric test power supply system has relatively high efficiency under different load conditions. An all-digital control is adopted by a power supply; compared with a traditional electric test power supply, the multi-purpose two-way power electric test power supply system has the characteristics of being small in size, light in weight, diverse in function and the like, and is suitable for the occasions of electric operation, an inspection experiment, storage battery charging and discharging and the like.

The invention discloses a primary edge control type switch power supply with high-precision constant-voltage/constant-current output and a high-pulse-frequency (PF) value. The primary edge control type switch power supply comprises an electromagnetic interference and filtering circuit, a rectifying filtering circuit, a transformer, a voltage stabilizing buffer circuit, a filtering shaping output circuit, a metal oxide semiconductor (MOS) tube, a sampling resistor and a constant-voltage and constant-current pulse frequency control (PFC) driving module, wherein the voltage stabilizing buffer circuit, the filtering shaping output circuit, the MOS tube, the sampling resistor and the constant-voltage and constant-current PFC driving module are connected in parallel with the transformer. The primary edge control type switch power supply has the advantages that the transformer primary edge is detected and is fed back to a PFC control chip, and a pulse frequency modulation (PFM) mode is adopted, so high-precision current and voltage can be output. Compared with the traditional driving circuit, the primary edge control type switch power supply has the advantages that peripheral devices such as optical couplers and the like are omitted, so a peripheral circuit is simpler, the PF value and the electric work efficiency of the whole power supply are obviously improved, and the primary edge control type switch power supply has the obvious characteristics that the periphery circuit is simple, the cost is low, and the performance is high. The large-scale popularization and application can be easily realized.

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.

The invention discloses a PFC dual-full-bridge-based intelligent sine wave voltage conversion circuit. The intelligent sine wave voltage conversion circuit comprises an input rectifying and filtering unit, a PFC voltage boosting unit, a full-bridge DC-to-DC isolation converter unit, an inversion phase reversal unit and a filtering inductor, wherein the full-bridge DC-to-DC isolation converter unit comprises a first switching tube, a second switching tube, a transformer, a first rectifying bridge, an eighth switching tube, a ninth switching tube and a first electrolytic capacitor; the inversion phase reversal unit is connected to the output end of the full-bridge DC-to-DC isolation converter unit for performing inversion conversion on the output voltage of the full-bridge DC-to-DC isolation converter unit and then outputting an alternating current; the front end of the filtering inductor is connected to the output end of the inversion phase reversal unit while the back end of the filtering inductor is connected with a load; and the filtering inductor is used for filtering high-frequency pulse and providing power frequency sine alternating current for the load. By adoption of the PFC dual-full-bridge-based intelligent sine wave voltage conversion circuit, the output voltage quality can be improved, and the high-frequency pulse in the output signal can be filtered.

The invention discloses a PFC forward full-bridge-based intelligent type correction filtering voltage conversion circuit. The PFC forward full-bridge-based intelligent type correction filtering voltage conversion circuit comprises an input unit, a PFC voltage boosting unit, an isolation type two-transistor forward converter and an inversion phase reversal unit, wherein the isolation type two-transistor forward converter comprises a first switching tube, a second switching tube, a first fly-wheel diode, a second fly-wheel diode, a second rectifying diode, a transformer, a filtering inductor, and a first electrolytic capacitor; the drain of the first switching tube is connected to the output end of the PFC voltage boosting unit; the source of the first switching tube is connected to the first end of a primary winding of the transformer; the second end of the primary winding of the transformer is connected to the drain of the second switching tube; the source of the second switching tube is connected with a front leading end; the gate of the first switching tube and the gate of the second switching tube are used for connecting the same PWM signals; and the inversion phase reversal unit is used for performing inversion conversion on the output voltage of the isolation type two-transistor forward converter and outputting an alternating current. By adoption of the intelligent type correction filtering voltage conversion circuit, the PF value and the output voltage quality can be improved.

The invention provides a contactor power saver, which comprises a main power circuit, a current sampling circuit, an error amplifying circuit and a PWM control circuit. The current sampling circuit samples a voltage signal of the main power circuit and outputs a current sampling signal. The error amplifying circuit compares the current sampling signal with a reference voltage and outputs an errorvoltage signal. The PWM control circuit detects the error voltage signal, outputs a drive signal with a constant frequency and a duty ratio proportional to that of the error voltage signal, and controls the on/off state of a switch tube in the main power circuit. By the invention, the power factor value can be increased to about 0.9V and the current of a contactor coil is constant under the wide-range input voltage. Modules of the control circuit can be integrated, the circuit is simple, and the cost is low.

The invention provides a multi-channel light-emitting diode (LED) linear driver which comprises a voltage regulation circuit, a linear regulation circuit, a plurality of LED lamp groups and a plurality of LED drivers. The voltage regulation circuit converting input voltage of alternating-current mains supply into direct-current voltage and outputs first direct-current voltage and second direct-current voltage, and the value of the first direct-current voltage is higher than that of the second direct-current voltage. The linear regulation circuit receives the second direct-current voltage from the voltage regulation circuit. The plurality of LED lamp groups are connected serially, each of the LED lamp groups is formed by at least one LED; one end of each of the LED drivers is connected to the cathode of each of the LED lamp groups to drive the LED lamp group to be turned on or turned off, the other end of each of the LED drivers is connected to the linear regulation circuit, the first direct-current voltage from the voltage regulation circuit is directly applied to the cathodes of the plurality of LED lamp groups, the linear regulation circuit drives each of the plurality of LED drivers to enter the linear regulation circuit sequentially according to changes of the input voltage.

The invention discloses a PFC flyback full-bridge-based intelligent sine-wave voltage conversion circuit, which comprises an input unit, a PFC booster unit, a flyback isolation converter unit and an inverse inverter unit, wherein the flyback isolation converter unit comprises a first switch tube, a transformer, a first rectifier diode, a filter inductor and a first filter capacitor; a first end of a primary winding of the transformer is connected to an output end of the PFC booster unit; a second end of the primary winding of the transformer is connected to a drain of the first switch tube; a source of the first switch tube is connected to front-end ground; a gate of the first switch tube is used for being connected to a PWM signal; the first end of a secondary winding of the transformer is connected to an anode of the first rectifier diode; a cathode of the first rectifier diode is connected to a front end of the filter inductor; a rear end of the filter inductor is taken as an output end of the flyback isolation converter unit; and the inverse inverter unit is used for outputting AC after inverse conversion. According to the PFC flyback full-bridge-based intelligent sine-wave voltage conversion circuit, the PF value can be improved and the quality of output voltage can be improved.

The invention discloses a PFC control method and device. Electric supply alternating voltages and an undistorted standard same-phase sine fundamental wave are compared, finally distorted signals with the proper number of fundamental waves are obtained, the distorted signals reflect the distortion situation of electric supply, the signals are used for controlling working currents of a PFC device, so that the working currents of the PFC device are in the half-wave form of electric supply, when heavy load happens instantly, the device consumes low working currents or does not consume working currents, when relatively-light load happens instantly, high working currents are consumed, so that electric supply voltage wave form distortion is reduced, therefore, the whole PF value of an electric unit is improved, other distortion load exists in the electric unit, the PFC device can still work well, and the whole PF value of the electric unit is improved.

The invention discloses a charger control circuit based on PFC and LLC topology wide range voltage output. The charger control circuit comprises a PFC main power circuit, an LLC converter, a feedback circuit, and a PFC control circuit. The power supply end of the PFC main power circuit is connected with AC input, and the output end of the PFC main power circuit is connected with the input end of the LLC converter and the sampling end a1 of the PFC control circuit. The input end of the PFC main power circuit is connected with the control end c1 of the PFC control circuit. The output end of the LLC converter is connected with the sampling end a2 of the feedback circuit. The output end b2 of the feedback circuit is connected with the input end b1 of the PFC control circuit. The charger is guaranteed to work in an optimal state in a wide output voltage range, and the efficiency of the charger is improved. The charger control circuit adopts hardware control, and has advantages of simple structure, high reliability, and low costs.

The invention discloses a high-performance current-type multi-switching LED controller, which comprises an input rectifier unit, a voltage sampling unit, a logic control unit, a current sampling unit, a constant current control unit, a switch array, capacitors, a resistor and an LED lamp string, wherein the logic control unit sends control signals to the switch array according to voltage and current signals acquired by the voltage sampling unit and the current sampling unit and controls the LED lamp string to realize three-switching or four-switching series-to-parallel conversion, and control signals are sent to adjust the current value of the constant current control unit. The high-performance current-type multi-switching LED controller has the advantages that no ripple wave does exist; EMI is low; the efficiency is high; the single-voltage input range is realized; the PF value is high; miniature, integration and low cost are realized; due to the method of voltage sharing by serial capacitors, self-adaption on input voltage changes is greatly expanded, the system efficiency is improved, and strong filter and power supply are provided for the LED; and due to the creative current monitoring self-lock switch, the system efficiency is greatly improved, the system size is reduced and the system cost is reduced.

The invention provides an LED (Light Emitting Diode) drive circuit. The LED drive circuit comprises a rectifier circuit, a drive current generation circuit, a bus voltage detection circuit, an LED structure control circuit and an LED array. According to the LED drive circuit provided by the invention, the LED array in the prior art is changed on the basis of reducing energy consumption or realizing a high PF (Performance Factor) value, and a utilization rate of each LED is adjusted through switching each switch, so that the utilization rate of the LED in the LED array is more uniform, thus the service life of the LED drive circuit is prolonged.

The invention discloses a PFC and LLC resonance-based intelligent half-bridge modified wave voltage conversion circuit, which comprises an input unit, a filter unit, a PFC booster unit, an LLC isolation converter unit and an inverse inverter unit, wherein the LLC isolation converter unit comprises a first switch tube, a second switch tube, a transformer, a first diode, a second diode and a filter inductor; a source of the first switch tubeis connected to a first end of a primary winding of the transformer; a second end of the primary winding of the transformer is connected to front-end ground through a first resonant capacitor; a drain of the second switch tube is connected to the first end of the primary winding of the transformer; the first end of a secondary winding of the transformer is connected to a cathode of the first diode; the second end of the secondary winding of the transformer is connected to an anode of the second diode; and the cathode of the second diode is connected to the front end of the filter inductor. According to the PFC and LLC resonance-based intelligent half-bridge modified wave voltage conversion circuit, the PF value and the quality of output voltage can be improved.

The invention discloses a PFC flyback full-bridge-based intelligent modified-wave voltage conversion circuit, which comprises an input unit, a PFC booster unit, a flyback isolation converter unit and an inverse inverter unit, wherein the flyback isolation converter unit comprises a first switch tube, a transformer, a first rectifier diode and a first electrolytic capacitor; a first end of a primary winding of the transformer is connected to an output end of the PFC booster unit; a second end of the primary winding of the transformer is connected to a drain of the first switch tube; a source of the first switch tube is connected to front-end ground; the first end of a secondary winding of the transformer is connected to an anode of the first rectifier diode; the second end of the secondary winding of the transformer is connected to rear-end ground; a cathode of the first rectifier diode is taken as an output end of the flyback isolation converter unit; and the inverse inverter unit is used for carrying out inverse conversion on output voltage of the flyback isolation converter unit and then outputting AC. According to the PFC flyback full-bridge-based intelligent modified-wave voltage conversion circuit, the PF value can be improved and the quality of the output voltage can be improved.

The invention discloses an intelligent boost conversion device having long lifetime. The intelligent boost conversion device comprises a high-frequency modulation unit, an induction filter unit and an inversion reverse phase unit, wherein the high-frequency modulation unit comprises an energy storage inductor and a first switching tube, a rear end of the energy storage inductor is connected with a drain of the first switching tube and a positive electrode of a freewheeling diode, a source of the first switching tube is connected with the ground, a grid of the first switching tube is used for accessing a PWM pulse signal, the induction filter unit comprises a filter inductor, a front end of the filter inductor is connected with a negative electrode of the freewheeling diode, a rear end of the filter inductor is connected with the inversion reverse phase unit, and the inversion reverse phase unit is used for converting a DC pulse voltage output from the rear end of the filter inductor to a sine AC voltage. By the intelligent boost conversion device, an electrolytic capacitor is not needed, the service lifetime can be prolonged, a PF value of a product is improved, the intelligent boost conversion device is convenient to carry, and moreover, the interference on a power grid can be prevented.

The invention discloses a CRM buck-boost converter controlled by segmented constant conduction time. The converter comprises a main power circuit and a control circuit, wherein the control circuit comprises an input voltage feed-forward circuit, a first multiplier, an RS trigger, a comparator, a first gating switch, a switching signal generation circuit, an output voltage feedback circuit, an ANDgate and NOT gate, a switching tube driving circuit and an output voltage sampling circuit; and the control circuit generates a control signal according to input voltage feedforward and output voltagefeedback of the main power circuit; two switching tubes in the main power circuit are driven to work, so that the conduction time of the converter working in the Buck stage and the conduction time ofthe converter working in the Buck/Boost stage in one power frequency period are different, the input current is closer to sine waves with the same phase as the input voltage, and the PF value is increased in the input voltage range. According to the invention, the power factor of the converter is improved, and the converter has the advantages of being small in inductive current peak value, smallin switching tube conduction loss and small in required diode stress.

The invention relates to a spotlight driving circuit. The spotlight driving circuit comprises a rectifier filter module, a power factor correction module, a primary side energy storage filter unit, a secondary energy storage filter unit and a winding energy storage filter unit. The primary side energy storage filter unit comprises a primary side coil. The secondary energy storage filter unit comprises a secondary coil. The winding energy storage filter unit comprises a winding coil. A transformer is formed by the three coils. The rectifier filter module is used to perform rectification and filtration on inputted electric energy and then output direct current to the power factor correction module. The power factor correction module is used to output the current which is subjected to power factor correction to the primary side coil. The secondary coil is used to generate an induced voltage and output the induced voltage to an LED light source. The winding coil is also used to generate an induced voltage to maintain the input voltage of the power factor correction module. The invention further relates to a spotlight. According to the invention, the current of the primary side coil of the transformer is controlled through the power factor correction module, so a high PF(power factor) value can be obtained, so that the effect of energy saving can be achieved.

The invention relates to the PFC circuit technology field and especially relates to a current compensation method of an input capacitor of a PFC circuit, the PFC circuit and a power conversion circuit. The invention discloses the current compensation method of the input capacitor of the PFC circuit, the PFC circuit and the power conversion circuit. The current compensation method of the input capacitor of the PFC circuit comprises the steps that a compensation current icbs is adopted to compensate a current icbb of an input capacitor cbb flowing through an alternating current input end of thepower conversion circuit, wherein the compensation current icbs is sinusoidal current, and a frequency is twice of the frequency of an input alternating current power supply. An influence of a currentphase shift of the input capacitor of the power conversion circuit on the input current can be effectively reduced, a PF value is improved, and a current working state of the circuit is not influenced.

The present invention provides an LED drive circuit. The LED drive circuit comprises a rectifying circuit, a driving current generation circuit, a bus voltage detection circuit, an LED structure control circuit and an LED array. The LED drive circuit provided by the present invention enables the LED array in the prior art to be changed on the basis of reducing the energy consumption or realizing a high power factor (PF) value, can adjust the utilization rate of each LED by switching the switches, and enables the utilization rates of the LEDs in the LED array to be more uniform, thereby increasing the service life of the LED drive circuit.

The invention discloses a digital universal light modulator which integrates an electromagnetic radiation suppression circuit, a rectifying circuit, a switch circuit, a low-power-consumption current amplification circuit and acceleration loop, a power supply circuit, a single-core or multiple-core microcontroller, a zero potential detecting circuit, a front/rear shifting switch, an upper/lower regulation ON/OFF digital coding incrementer. The digital universal light modulator can change dimming/speed-regulation into front shifting or rear shifting waveforms according to different loads so as to achieve the purpose that any load is accessible, and the loads include loads of a halogen lamp, an electronic transformer, a CFL lamp tube stabilizer, a front shifting LED lamp, a rear shifting LED lamp, a fan speed regulator and the like different in capacitive character, inductive character and resistive character.

The invention discloses an intelligent correction wave voltage conversion circuit based on a PFC dual full bridge. The circuit comprises an input rectification filtering unit, a PFC boosting unit, and a full-bridge DC-DC isolation transformer unit, a drain electrode of a first switch tube is connected to an output terminal of the PFC boosting unit, a source electrode of the first switch tube is connected to a first terminal of a primary winding of a transformer, a drain electrode of a second switch tube is connected to the source electrode of the first switch tube, a source electrode of the second switch tube is connected to the front-end ground, a drain electrode of an eighth switch tube is connected to the output terminal of the PFC boosting unit, a source electrode of the eighth switch tube is connected to a second terminal of the primary winding of the transformer, a drain electrode of a ninth switch tube is connected to the source electrode of the eighth switch tube, a source electrode of the ninth switch tube is connected to the front-end ground, a secondary winding of the transformer is connected with an input side of a first rectification bridge in parallel, and a positive electrode of an output side of the first rectification bridge is regarded as an output terminal and connected to an inversion phase-inversion unit. According to the circuit, the quality of the output voltage can be improved.

The invention discloses an intelligent sine-wave voltage conversion circuit based on a PFC (power factor correction) forward half-bridge. The circuit comprises an input rectifier filter unit, a PFC voltage boosting unit, an isolated two-transistor forward converter and an inversion reverse-phase unit, wherein the isolated two-transistor forward converter comprises a first switch tube, a second switch tube, a first diode, a second diode, a third diode, a fourth diode, a transformer and a filter inductor; the inversion reverse-phase unit comprises a fourth switch tube, a fifth switch tube, a third electrolytic capacitor, a fourth electrolytic capacitor and a first filter inductor, a grid of the fourth switch tube and a grid of the fifth switch tube are used for accessing two ways of PWM (pulse width modulation) pulse signals with opposite phases respectively, a source of the fourth switch tube is further connected to the front end of the first filter inductor, a negative pole of the third electrolytic capacitor is connected to a positive pole of the fourth electrolytic capacitor, and the rear end of the first filter inductor and the negative pole of the third electrolytic capacitor are taken as output ends of the inversion reverse-phase unit. With the adoption of the circuit, PF (power factor) value and output voltage quality can be improved.