84results about How to "Small voltage ripple" patented technology

The invention belongs to the technical field of air-conditioner compressor control, and provides an air-conditioner compressor control circuit and a variable frequency air-conditioner. AC-DC conversion is performed on AC outputted by an AC power supply by a three-level PFC converter so that DC is generated. After power factor correction processing is performed on DC according to a correction control signal outputted by a control module, positive level and negative level are outputted to a three-level inverter via a DC bus. Positive level, negative level and zero level are modulated by the three-level inverter according to an inversion control signal outputted by the control module, and U-phase AC, V-phase AC and W-phase AC are outputted to a motor of an air-conditioner compressor from the U-phase output end, the V-phase output end and the W-phase output end of the three-level inverter respectively so that voltage ripple of the DC bus is reduced, jump range of output voltage is reduced, harmonic wave in current of the motor of the air-conditioner compressor is reduced, torque pulsation of the motor is reduced, and thus objectives of reducing noise level of the air-conditioner and enhancing integral efficiency of the air-conditioner are achieved.

An energy-based oriented switching mode power supply includes a bi-directional converter having an energy input and a load output, and an energy based pulsed generator connected between the energy input and the load output for outputting a gate voltage signal controlling how much energy is supplied from the energy input. The energy based pulsed generator receives a clock signal and outputs the gate voltage signal according to the load output of the bi-directional converter when the clock signal is at a high level. Accordingly, the switching mode power supply achieves a hybrid of PWM and PFM, depending on the energy demand of the load output, for a fast transient response and a small voltage ripple whilst improving power efficiency over a wide load range.

The invention discloses a two-path parallel connection-based two-phase type wireless electric energy transmission device. The device comprises a power source, a load, a first wireless electric energytransmission circuit, a second wireless electric energy transmission circuit, and a control signal generation circuit; the first wireless electric energy transmission circuit and the second wireless electric energy transmission circuit are connected in parallel; and the control signal generation circuit is used for generating two pairs of pulse control signals with a phase difference of 90 degrees, wherein the two pairs of pulse control signals are respectively applied to the control ends of the first wireless electric energy transmission circuit and the second wireless electric energy transmission circuit. According to the two-path parallel connection-based two-phase type wireless electric energy transmission device of the invention, a novel circuit structure design is adopted, a two-pathparallel connection transmission topological structure is adopted to decrease the current burden of a single path; the ripples of the output direct-current voltages of two paths can be weakened by each other by means of phase shift control, so that the ripple coefficients of the direct-current output voltages can be reduced; and the current transmission capability of the device can be greatly improved under the premise of identical single-path transmission capability, and power obtained by the load can be improved. The two-path parallel connection-based two-phase type wireless electric energytransmission device has high popularization value and practical value.

The invention provides a composite multi-level power conversion circuit and method. The composite multi-level power conversion circuit comprises a single DC bus power supply, a bus voltage-dividing capacitor unit, an H bridge unit and at least one switch capacitor unit. The bus voltage-dividing capacitor unit comprises a capacitor bank string, a first positive string bridge arm and a second positive string bridge arm; each switch capacitor unit comprises a third positive string bridge arm, a switch capacitor and a middle bridge arm; the H bridge unit comprises a left bridge arm and a right bridge arm; the midpoint of the left bridge arm and the midpoint of the right bridge arm are used as the AC voltage output ends of the composite multi-level power conversion circuit; the composite multi-level power conversion circuit is provided with nine working modes which are a first working mode, a second working mode, a third working mode, a fourth working mode, a fifth working mode, a sixth working mode, a seventh working mode, an eighth working mode and a ninth working mode. The composite multi-level power conversion circuit and the method have the advantages of few power devices, multipleoutput levels and simple modulation strategy.

The invention provides a rail vehicle electric energy absorbing device, comprising at least two parallel electric energy absorbing modules. Each electric energy absorbing module comprises a buck/ boost unit, an energy storage unit, a master control unit and a current sharing control unit, wherein the inlet side of the buck/ boost unit is in connection with the inlet side of a traction system, and the opposite side is in connection with the energy storage unit; one side of the current sharing control unit is in connection with a vehicle network system, and the opposite side is in connection with the master control unit; and the master control is respectively in connection with the buck/ boost unit, current sharing control unit and vehicle network system. Each master control unit adjusts the charging current and discharging voltage of each energy storage unit and keeps the charging current and discharging voltage consistent. According to the utility model, the rail vehicle electric energy absorbing device can be used for solving the problem that the charging current and discharging voltage of each energy storage unit in a rail vehicle can not be kept consistent, thereby allowing the rail vehicle to drive in a reserved speed.

The invention discloses an inter-phase current balance control system suitable for hysteresis control of a high-frequency double-phase Buck converter, which is characterized in that each phase is provided with an average inductive current detection module to obtain an average inductive current value, and then the average inductive current value of the two phases is input into a current balance module to obtain inductive current difference value information; according to the inductive current difference information, the duty ratio of the two phases is adjusted in real time through the main comparator 1 and the main comparator 2, and finally the inductive current of the two phases is balanced. According to the control system, the problem of current equalization under the high-frequency condition is solved, the inductive current detection precision is high, the current equalization effect is good, and compared with a traditional digital control method, the energy loss is low, and the occupied area is small.

The invention discloses an inductive power transfer system and a control method and control system therefor. An inductive power transfer circuit comprises a direct current power supply module, a modular multi-level inverter and an inductive power transfer module; the direct current power supply module is connected with the modular multi-level inverter; the modular multi-level inverter converts a direct current provided by the direct current power supply module into a high-frequency alternating current; the inductive power transfer module is connected with the modular multi-level inverter; andthe inductive power transfer module is used for outputting the high-frequency alternating current voltage to a load in an electromagnetic induction form. The modular multi-level inverter-based inductive power transfer system provided by the invention belongs to the high-frequency power transfer system, so that high-power power transfer can be realized; and in addition, the modular multi-level inverter has a common direct current bus, so that installation of an independent direct current power supply in each sub module is not needed, thereby greatly reducing the size of the apparatus and lowering the cost of the inductive power transfer system.

The invention discloses a wind power converter control method, and provides a wind power converter. The wind power converter comprises a grid-side converter, a machine-side converter, a grid-side controller and a machine-side controller, wherein the grid-side controller controls the grid-side converter to adopt three-level unipolar wave generation, and the machine-side controller controls the machine-side converter to adopt three-level unipolar wave generation. According to the wind power converter control method, three-level topology direct current bus voltage ripples can be reduced, the advantages that three-level topology network side current harmonics are small, the machine side voltage du/dt and the voltage peak are small are kept, and the cost and the size of the converter are not increased. Meanwhile, the invention further discloses a power equipment control device and the converter.

The invention discloses a low-ripple switched-capacitor common-mode feedback structure. Two sets of MOS transistors which are connected into a diode are inserted between common-mode feedback output and a fully differential operational amplifier to achieve filtering of common-mode output signals, and therefore ripples of original output common-mode feedback signals are reduced. The low-ripple switched-capacitor common-mode feedback structure aims at reducing the voltage ripples of the feedback signals of a common-mode feedback circuit in the fully differential operational amplifier, the influences of small signals caused by clock feedthrough and capacitor charging and discharging on the fully differential operational amplifier are greatly reduced, and the output precision of the fully differential operational amplifier is improved. In addition, a traditional switched-capacitor common-mode feedback circuit needs a larger sampling capacitor, but in the low-ripple switched-capacitor common-mode feedback structure, the fewer ripples are achieved by using a smaller sampling capacitor, the load capacitor size is reduced, and the unity-gain bandwidth of the fully differential operational amplifier is increased.

The invention provides a direct-current generator. The direct-current generator comprises a first end cover component, a second end cover component, a machine shell component, a main stator, a main rotor, an exciter and a terminal component, wherein the first end cover component and the second end cover component are fixedly connected to the two ends of the machine shell component respectively, the main stator is fixedly arranged inside the machine shell component and is coaxial with the machine shell component, the main rotor is fixedly arranged on a rotary shaft coaxial with the machine shell component, located inside the main stator and coaxial with the main stator, the exciter is fixedly arranged inside the first end cover component and is coaxial with the machine shell component, and the terminal component is located outside the machine shell component. According to the direct-current generator, wiring is easy, installation and maintenance are easy, voltage rippers are small, and electrical performance is high.

The invention belongs to the technical field of analog circuits, and particularly relates to a BUCK-BOOST with a high-precision low-ripple light-load working mode. According to the scheme, an intermittent working mode is replaced by a monopulse mode, and in a light load mode, the power level only works for one cycle each time, so that voltage ripples can be reduced; the Vc signal is used for modulating the interval time of the monopulse mode, and the lighter the load is, the longer the interval time is. The purpose is that the working frequency of the power level is linearly reduced along with the load, and the audio frequency can be entered only when the load is very light. And meanwhile, as only one cycle is operated each time, the transmitted energy is small, and the audio noise is far lower than the noise of the scheme shown in the figure 3. The system modulates the interval time by using the average value of the Vc, and can ensure that the voltage precision of the VOUT does not change along with the VIN, the VOUT and the load.

The embodiment of the invention provides a high-voltage DC conversion circuit and a vehicle-mounted charger. The high-voltage DC conversion circuit comprises a DC input end, a DC output end, a controlunit and a plurality of resonant converters. The input ends of the resonant converters are connected to the DC input end in parallel, and the output ends of the resonant converters are connected between a positive output terminal and a negative output terminal of the DC output end in series. Each resonant converter comprises a DC-to-AC conversion subunit, a resonant network and an AC-to-DC conversion subunit. Under the control of the control unit, the phases of the output voltages of the DC-to-AC conversion subunits of the resonant converters are spaced by a preset angle. According to the embodiment of the invention, the primary windings of the resonant converters are connected in parallel and the secondary windings are connected in series, and the phases of the output voltages of the DC-to-AC conversion subunits of the resonant converters are spaced by the preset angle, so that the voltage ripple of the DC output end of the high-voltage conversion circuit can be significantly reduced.

The invention discloses a three-port clamping type back-to-back bridgeless three-level rectifier, and belongs to the technical field of power electronic converters. The three-port clamping type back-to-back bridgeless three-level rectifier comprises a three-port clamping structure and a traditional rectifier bridge arm structure. Compared with a traditional rectifier bridge arm, the three-level rectifier has the advantages that the three-port structure is used for clamping the capacitor voltage so that the voltage stress borne by each semiconductor device in the three-port structure is reduced. Meanwhile, an additional power branch is provided to be directly connected to the midpoint of the series capacitor. According to the three-level rectifier, an extra power channel is provided, and meanwhile, due to the fact that a new diode structure is added, the stability and reliability of a circuit are improved. Compared with a traditional two-level rectifier, the rectifier has the advantages that the number of levels of phase voltage on the alternating current side can be three, and the capacitance value can be remarkably reduced; the voltage stress of the device is reduced; the cost of capacitors and semiconductor devices is reduced; and the size of the circuit is correspondingly increased due to the complexity of the three-port structure.