111results about How to "Reduce drive loss" patented technology

The invention relates to a combined controller of an LLC series resonant converter. It includes a bridge circuit, the bridge circuit drives a resonant network, a transformer, a frequency modulation controller, a duty cycle controller, an output rectifier circuit, an output voltage detection circuit and an output current detection circuit, the resonant network is connected in series with the primary side of the transformer, and the resonant The network is connected in series between the midpoint of the bridge circuit and the transformer, the filter capacitor is connected in parallel at the output end, the output voltage sampling circuit samples the output voltage value and sends it to the frequency modulation controller and the duty ratio controller, and the output current detection circuit samples the output current value at the same time sent to the duty cycle controller. The driving waveform is comprehensively adjusted by the frequency modulation controller and the duty cycle controller and sent to the bridge circuit for voltage regulation. The invention realizes the low-frequency narrow starting pulse, reduces the impact current of the power switch when starting; realizes the low-frequency narrow starting pulse work under no-load, deep current limiting and short-circuit working conditions, reduces the impact current of the power switch, and reduces the driving loss.

In a switching power supply apparatus, a first switching element is controlled by a driving voltage output from a switching control IC. A second switching control circuit controls the on-time of a second switching element so that the time ratio of the on-time of the second switching element to the on-time of the first switching element becomes almost constant with respect to a change in a load current. In a normal load state, since a square wave output from a frequency setting unit within the switching control IC is output with no change, a converter operates in a current-continuous mode. In a light load state, a driving signal generation unit within the switching control IC is subjected to blanking with the period of a signal output from a maximum frequency setting unit and an oscillation frequency is reduced. Accordingly, the converter operates in a current-discontinuous mode.

Disclosed is an adaptive current source drive circuit, comprising a current source drive circuit and a voltage adjusting circuit, wherein the voltage adjusting circuit feeds back the parameter change by acquiring a main circuit, obtains a reference voltage, and dynamically adjusts the driving circuit of the current source drive circuit, thus realizing adaptive current source driving. According to the circuit structure, the high frequency driving loss and the switch loss is reduced, and the system efficiency is optimized within the wide load scope.

A power switch tube isolated gate drive circuit for a power converter comprises a pulse width modulation driver, an isolation driving transformer T, a blocking capacitor Cb, a capacitor C1, a diode D and a driven switch tube Q which constitute an isolated gate drive circuit in the prior art. According to the invention, on the basis of the above circuit, a resistor R1 in parallel with the capacitor C1 is additionally installed; a capacitor C2 is additionally installed to be in parallel connection with a resistor R2 and connected to a cathode of the diode D; after the capacitor C2 and the resistor R2 are in parallel connection, the other end of the capacitor C2 is connected between the capacitor C1 and a grid electrode of the driven switch tube Q. The capacitor C2, the resistor R2 and the diode D form a negative voltage source to provide a stable negative voltage in turn-off of the switch tube Q. Accidental switch-on of the switch tube in the switch-off process because of various crosstalks is prevented, and the reliability of the system is raised.

A control device is configured to sufficiently reduce the drive loss of a hydraulic pump. The control device is provided with a controller configured to control a regeneration valve to switch to a regeneration state, and to control the flow rate of a second hydraulic pump to reduce the ejection flow rate of the second hydraulic pump in accordance with regeneration of hydraulic oil through the regeneration valve when a combined operation of lowering a boom and pressing an arm is performed. The controller outputs a command for setting the number of rotations of an engine to be smaller than the rotation number designated by a rotation number designating unit when the ejection flow rate of the second hydraulic pump is not larger than a predetermined flow rate during the combined operation.

The invention relates to a voltage modulation circuit capable of increasing light load efficiency, comprising a voltage reduction power switching circuit and a limitation voltage modulation circuit, wherein the limitation voltage modulation circuit senses the level of electric current of the output end of the voltage reduction power switching circuit, judges the light load state or the medium-high load state of the load according to the level of the electric current, and regulates the level of the output voltage used for pushing the driving end of an automatic switch in a switch driver, namely when the output electric current of the voltage reduction power switching circuit is lower and tends to be zero, the current load is indicated to be in the light load state, and the limitation voltage modulation circuit can lower the driving voltage of the automatic switch by regulation so as to realize the function of reducing the driver loss; and on the other hand, when the output electric current of the voltage reduction power switching circuit is increased, the load is indicated to be in the medium-high load state, and the limitation voltage modulation circuit can increase the driving voltage of the automatic switch by regulation so as to reduce the conduction loss.

The invention discloses a hybrid control method and device of a four-switch Buck-Boost converter. The hybrid control method comprises a digital control mode and an analog control mode and comprises the following steps of: respectively obtaining a digital control signal and an analog control signal according to an output voltage error signal in the working process; then generating a hybrid control signal according to the analog control signal and the digital control signal; when the load at the output end of the converter does not jump, adopting the hybrid control signal to control the switch motions of switch tubes in the converter so as to keep the output voltage at a constant value; and when the load at the output end of the converter jumps, adopting the hybrid control signal to control the switch motions of the switch tubes in the converter so as to rapidly restore the output voltage to the constant value. The hybrid control method and device have the characteristics of simple control scheme, high dynamic response speed and high steady state accuracy.

The invention discloses a resonant gate driving circuit suitable for a high-frequency application. The resonant gate driving circuit comprises a resonant capacitor Cr, a resonant inductor Lr, an auxiliary switching tube 1, an auxiliary switching tube 2, a main switching tube 1, a main switching tube 2 and a main power device Q1. The resonant capacitor Cr is connected in series with the resonant inductor Lr, the resonant inductor Lr is connected to a source electrode of the auxiliary switching tube 1, a drain electrode of the auxiliary switching tube 1 is connected to a drain electrode of the auxiliary switching tube 2, a source electrode of the auxiliary switching tube 2 is connected to a source electrode of the main switching tube 1, a drain electrode of the main switching tube 2 and a gate of the main power device Q1, a drain electrode of the main switching tube 1 is connected to a positive power supply voltage VCC, and a source electrode of the main switching tube 2 is connected tonegative power supply voltage VEE. According to the driving circuit of the invention, the resonant capacitor Cr, the resonant inductor Lr and the four switching tubes S1, S2, S3 and S4 are used to achieve gate resonant driving, the driving circuit can recover gate driving power, the driving circuit loss is reduced, and the switch-on and switch-off times of the main power device are shortened.

A seal ring has both low leakage characteristics and low friction characteristics to reduce the drive loss of the transmission of an automobile, thereby contributing to the improvement of fuel consumption of the automobile. A seal ring which is mounted in a shaft groove formed in the outer peripheral surface of a shaft has recesses formed in the seal ring. The recesses are disposed on the inner peripheral side of at least a contact side surface of the seal ring so as to be separated from each other in the circumferential direction. The recesses each have, formed on the inner peripheral side thereof, inners walls and an oil introduction hole which opens toward the inner peripheral surface of the recess. Such inner walls may be provided at both ends of each of the recesses in the circumferential direction, or one such inner wall may be provided only on the trailing side of the recess in the rotational direction.

A bipolar junction transistor (BJT) auto-excitation type Zeta convertor with a low main switch tube drive loss comprises a main loop of the Zeta convertor and a drive unit of a main switch tube Q1, wherein the main loop is assembled by an input capacitor Ci, a PNP type BJT Q1, an inductor L1, a capacitor C, a diode D, a diode D1, an inductor L2 and a capacitor Co, and the drive unit of the main switch tube Q1 is formed by a resistor R1, a resistor R2, a resistor R3, a resistor R4, a NPN type BJT Q2 and a PNP type BJT Q3. The converter has the advantages of being simple in circuit structure, few in component, low in main switch tube drive loss and high in circuit efficiency during light load.

The invention discloses a switching converter and a control method thereof. The switching converter comprises an input power positive electrode, an output voltage positive electrode, a power common ground, a switching tube Q1, a switching tube Q2, a switching tube Q3, a diode D1, an inductor L1 and a capacitor C1; a drain electrode of the switching tube Q1 is connected to the input power positive;a source electrode of the switching tube Q1 and a drain electrode of the switching tube Q2 are connected to one end of the inductor L1; a source electrode of the switching tube Q3 and a negative electrode of the diode D1 are connected to the other end of the inductor L1; a drain electrode of the switching tube Q3 is connected to one end of the capacitor C1; and a source electrode of the switchingtube Q2, a positive electrode of the diode D1 and the other end of the capacitor C1 are connected to the power common ground. According to the switching converter provided by the invention, the problem of low comprehensive efficiency of a step-down circuit working in a wide input voltage and a load range is solved, and meanwhile, oscillation is eliminated and EMI is improved.

The invention relates to a synchronous rectification control method and device for a phase-shifted full-bridge/push-pull bidirectional converter, belongs to the technical field of converter rectification control, and solves the problem of low light load efficiency in a buck mode caused by an OR logic driving mode of a full-bridge phase-shifted driving signal in the prior art. A primary side circuit of the bidirectional converter comprises a leading arm upper bridge arm switch S1, a leading arm lower bridge arm switch S3, a lagging arm upper bridge arm switch S2 and a lagging arm lower bridge arm switch S4. The secondary side circuit comprises a first synchronous rectification switch SR1 connected with the synonym end of the secondary side winding and a second synchronous rectification switch SR2 connected with the dotted end of the secondary side winding; the method comprises the steps that when the bidirectional converter works in a buck mode, driving levels of switches S1-S4 are received, AND logic operation is carried out on the driving levels of the switches S1 and S4, and a driving level of a switch SR1 is generated; and performing AND logic operation on the driving levels ofthe switch S2 and the switch S3 to generate a driving level of the switch SR2. And the efficiency problem of the converter under light load is improved.

The invention provides a GaN charger control circuit, which comprises: a charging circuit and a GaN driving circuit, and the charging circuit is electrically connected with the GaN driving circuit; wherein the GaN driving circuit comprises a PWM (Pulse Width Modulation) controller and a GaN MOS (Metal Oxide Semiconductor) tube; wherein the PWM controller is used for controlling the operation frequency of the charging circuit; and the GaN MOS tube is used for driving the charging circuit to start according to the operation frequency. The invention has the beneficial effects that: GaN (third-generation device) gallium nitride is matched with a high-frequency and high-efficiency PWM driving chip control circuit, lower driving loss is realized, lower Miller effect/lower switching loss are achieved, oscillation is small, and the corresponding switching loss and EMI are better. The gallium nitride technology is applied to a high-power charger, so that the conversion efficiency is higher and is up to 93% or above, the switching speed is higher, the working frequency is 100-500KHZ or above, and the purposes of high efficiency and energy conservation are achieved. By adopting the gallium nitride technology, the specification design of the element can be simplified, and a smaller size appearance can be achieved.

Provided is a self-excited BJT type bridgeless Cuk PFC rectification circuit. The rectification circuit comprises an input capacitor Ci, an NPN type BJT transistor Q1, an NPN type BJT transistor Q2, an NPN type BJT transistor Q3, an NPN type BJT transistor Q4, an NPN type BJT transistor Q5, an NPN type BJT transistor Q6, an NPN type BJT transistor Q7, a diode D1, a diode D2, a diode D3, a diode D4, a diode D5, a diode D6, a diode D7, a diode D8, an inductor L1, an inductor L2, an inductor L3, a capacitor Cs, an output capacitor Co, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, and a controlled current source group M1. According to the rectification circuit, the structure of a driving circuit is simplified, the driving efficiency is high, and easy self-running performance is obtained.

The drive set includes a base, a collar extension setup on the base, and a magnet located inside the collar extension. Characters are that the drive set also includes a first and a second lens drive modules setup inside same collar extension and the magnet jointly. The first lens drive module consists of first coil inside the magnet, first lens supporter and lens setup inside the first coil. The second lens drive module consists of second coil inside the first coil, second lens supporter and lens setup inside the second coil. Two drive modules share the collar extension and the magnet so as to make drives set miniaturization. Friction tabling between lens supporters and the collar extension makes supporters possible to move smoothly. Installed spring guarantees stabilizing force for the lens supporters. Thus, it is difficult to shake lens supporters even if camera is suffered from bump or impulsion. Features are: excellent impact resistance, simplified structure and few parts.

The embodiment provides a perpetual magnet synchronous motor control method and control device and air conditioner, can at the running of a motor selecting the most suitable control means of a vertical shaft current, reducing the loss of the starting of a compression engine; the method includes, capturing a tonal modification rate; according to the tonal modification rate ascertaining the control means of the vertical shaft current, when the tonal modification rate satisfying the condition of the control means of a weak magnet, using the control means of the weak magnet to generate an order value of the vertical shaft current; when the tonal modification rate satisfying the condition of the control means of the lowest copper loss, using the control means of the lowest copper loss to generate an order value of the vertical shaft current; according to the order value of a preset motor rotating speed and the rotating speed of the motor calculating the order value of a reciprocal shaft current; according to the vertical shaft current and the order value of the vertical shaft current calculating the run time value of the vertical shaft current; according to the reciprocal shaft current and the order value of the reciprocal shaft current calculating the run time value of the reciprocal shaft current; according to the run time value of the vertical shaft current and the run time value of the reciprocal shaft current and the angle of the perpetual magnet synchronous motor rotary generating a six route drive signal for controlling the perpetual magnet synchronous motor. The perpetual magnet synchronous motor is applied in tonal modification air conditioners.

The invention discloses a gallium nitride device and a driving circuit thereof. The gallium nitride device comprises: a substrate (100); a gallium nitride (GaN) buffer layer (200) formed on the substrate (100); an AlGaN (AlGaN) barrier layer (300) formed on the GaN buffer layer (200); the source electrode (S), the drain electrode (D) and the grid electrode are formed on the AlGaN barrier layer (300); wherein the grid electrode comprises a P-type doped gallium nitride P-GaN cover layer (400) formed on the AlGaN barrier layer (300), and first grid electrode metal (M1) and second grid electrode metal (M2) formed on the P-GaN cover layer (400), Schottky contact is formed between the first grid electrode metal (M1) and the P-GaN cover layer (400), and ohmic contact is formed between the second grid electrode metal (M2) and the P-GaN cover layer (400). The gallium nitride device is a normally-closed device, so that the design of a driving circuit is facilitated; moreover, the gallium nitride device is provided with a mixed gate structure composed of a Schottky gate and an ohmic gate, so that the gate electric leakage in the conduction process can be reduced, the driving power consumption is reduced, a large number of holes can be injected into the AlGaN barrier layer during conduction, the dynamic resistance is optimized, and the reliability of the device is improved.

The invention discloses an interleaved resonant converter and a control method. The interleaved resonant converter comprises a DC power supply, an inverter circuit, a resonant circuit, a transformer circuit, a rectifier circuit and a filter circuit. The resonant converter further comprises a sampling control circuit which is respectively connected with the primary side orand the secondary side ofthe inverter circuit, the rectifier circuit, the filter circuit and the transformer circuit. The output voltage is regulated by sampling control circuit, frequency conversion control inverter circuitand delay control rectifier circuit, the delay control is realized based on the zero-crossing point delay in the secondary current or the primary current to turn off the corresponding secondary switching transistor. The delay control increases the energy in the resonant circuit, which makes the interleaved resonant converter have the boost characteristic. The interleaved resonant converter reducesthe control frequency range greatly to realize the wide input voltage range andor the wide output voltage range, thus solving the problem the the output voltage range of the resonant converter is narrow and the control frequency range is large.