378results about How to "Reduce current ripple" patented technology

The invention discloses a grid-connected photovoltaic inverter and relates to equipment which employs irreversible DC power input conversion as AC power output for a semiconductor device with a control electrode and is used for being used together with a power supply system of a power supply. The equipment consists of a photovoltaic array module, four identical switching tubes, two identical diodes, four identical capacitors, an inductor and a power grid; and the topology ensures not to generate DC component or common mode current for the power grid. Meanwhile, the inverter has low output current ripple and higher efficiency, and overcomes the defects that the conventional full-bridge inverters and other types of transformerless photovoltaic inverters generate DC component in the power grid and generate common mode current or/and higher current ripple. Compared with a half-bridge inverter, the grid-connected photovoltaic inverter reduces the differential mode voltage and current ripple by half.

A full wave DC/DC converter magnetically integrates into the transformer assembly the functions of the resonant inductor, magnetizing inductor and the output filter inductor. The primary and the secondary windings are assembled on a gapped center leg of an E-core, while two output filter windings with an equal number of turns are assembled on gapped left and gapped opposed side legs of the E-core. The length of the gaps in the side legs is selected so that the DC current does not saturate the side legs. The two filter windings are connected in series and are oppositely polarized so that the voltages induced in these windings by the primary winding flux cancel each other.

The utility model relates to a voltage type source rectifier stable control system and method based on LCL filter wave, belonging to the source rectifying technical range of electronic technology. The system comprises a DC voltage control cell, a current control cell, an active damp control cell and a voltage space vector generating cell. the utility model produces six PWM signals to gain the current signal of the filter wave capacitor branch directly or indirectly, outputs the reference value of the damp voltage and achieves the stable control on the system. The method provides an adjustable sine control on the DC voltage output and input current through the active damp vector control of the voltage type source rectifier stable control system, the damp voltage reference value outputted by the active damp vector control cell, and the network voltage to execute summation operation. The utility model has the advantages of controllable DC voltage, low aberrance rate of the network input current, high power factor, satisfying the requirement of energy double-redirection flowing, and achieving the stability of the system without increasing the quantity of hardware damp resistance.

The invention provides a dimmable LED (Light-Emitting Diode) driving circuit and a driving method. An input current in a first power-level circuit is controlled as a square wave signal within a rectifier conducting time interval by an input current control circuit, the peak value of the input current is a constant value and meets the requirement of the minimum load current of an electronic transformer, and the valley value of the input current is zero; and the input current is kept at zero within a rectifier nonconducting time interval. The load current of the electronic transformer can be kept larger than the minimum load current, and thus, a normal working state can be kept in the working process, and the problem of LED load flicker caused by the switching off of the electronic transformer is avoided; in addition, information on the input current is detected through a dimmable signal generating circuit so that a dimmable signal for representing information on a conduction angle of a rectifier is obtained, an LED load is precisely dimmed, the dimming range is wide, and the dimming effect is good; and finally, constant-current control for the current of the LED load is realized by an output current control circuit, and therefore, the brightness stability of the LED load is ensured.

A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

An embodiment of the invention discloses a PFC circuit compatible with single-phase and three-phase AC inputs and a control method thereof. The PFC circuit detects input states of a mains supply and athree-phase voltage by means of a voltage detection module, and feeds back detection results to a control module; the control module outputs a driving signal and a control signal according to the detection results; an input switch changeover module controls an on-off state of an internal switch according to the driving signal, accesses a live wire of an arbitrary phase among three phases of livewires to a three-phase PFC power module so as to enter a single-phase operating mode, or accesses all the three phases of live wires to the three-phase PFC power module so as to enter the single-phaseoperating mode; the three-phase PFC power module rectifies or inverts the mains supply according to the control signal; two bridge arms of the three-phase PFC power module are subjected to parallel output in the single-phase operating mode, so as to obtain twofold single bridge arm output power; and the two bridge arms are staggered and connected in parallel to perform rectification or inversion,so that current ripples of the two bridge arms counteract each other. The PFC circuit solves the problems that the existing single phase outputs 1/3 power, positive and negative bus voltages are imbalance and the ripples are large.

The invention discloses a backlight controller, a method for driving light sources, and a display system. The backlight controller includes a feedback circuitry, a phase array circuitry, and an encoder circuitry. The feedback circuitry is coupled to the plurality of light source strings and generates a plurality of feedback signals indicative of a plurality of currents flowing through the plurality of light source strings respectively. The phase array circuitry receives a dimming control signal and receives a code signal indicative of a total number of operative light source strings among the plurality of light source strings, and generates a plurality of phase shift signals according to the code signal and the dimming control signal. The encoder circuitry is coupled to the phase array circuitry and receives the plurality of phase shift signals and the plurality of feedback signals, and generates a plurality of pulse width modulation signals to respectively control the operative light source strings. The backlight controller can detect the light source strings in service among a plurality of light source strings, provide automatic phaseshift regulation based on the total number of the light source strings in service, so as to optimize the burst mode light regulation and reduce the ripple current in power line.

The invention discloses a wide-range bidirectional conversion circuit and a control method. The wide-range bidirectional conversion circuit comprises a three-stage bidirectional converter and a control unit, and the three-stage bidirectional converter is formed by sequentially connecting a non-isolated DC/DC converter, an isolated DC/DC converter and a DC/AC inverter. When the system works in theforward direction, a direct-current power supply or energy storage equipment realizes grid-connected energy feedback through the non-isolated DC/DC converter, the isolated DC/DC converter and the DC/AC inverter; and during reverse working, an alternating voltage supplies power to a direct-current load or charges an energy storage device through a rectifying circuit, the isolated DC/DC converter and the non-isolated DC/DC converter. In order to adapt to different power levels and realize higher input current ripple control, the non-isolated converter adopts a multi-phase interleaved parallel structure; and in order to further broaden the requirements of input and output ranges in practical application, the isolated converter can be controlled by adopting a full-bridge/half-bridge variable structure. The whole system has the advantages of wide input direct-current voltage range, wide output alternating-current voltage range, wide load range, small current ripple, high-frequency isolation, high efficiency, energy conservation, environmental protection and the like.

The system comprises a first motor for applying rotational energy to a respective first wheel of the vehicle. A second motor is arranged for applying rotational energy to a respective second wheel of the vehicle. A first inverter is coupled to the first motor, where the first inverter is capable of receiving direct current electrical energy from the direct current bus. The first inverter is configured to provide a first group of alternating currents with a corresponding reference phase. A second inverter is coupled to the second motor. The second inverter is capable of receiving direct current electrical energy from the direct current bus. The second inverter is configured to provide a second group of alternating currents with a phase shift with respect to the reference phase, such that the phase shift is effective to reduce the direct current ripple on the direct current bus.

The invention discloses an electromagnetic dual-salient pole motor driving and charging integrated system of a complex excitation winding. The system comprises a storage battery, a charge-discharge converter, an electromagnetic dual-salient pole motor, an inverter, an EMIS filter and a charge-discharge changeover switch, wherein the charge-discharge converter comprises seven IGBTs, two diodes anda segmented excitation winding of the electromagnetic dual-salient pole motor. By segmented excitation winding connection mode and control mode, the electromagnetic dual-salient pole motor can be applied to an electric vehicle driving and charging integrated system, an excitation control loop of the electromagnetic dual-salient pole motor and an inductance phase in the storage battery charge-discharge converter are integrated, and the total loss of the system is reduced; the excitation winding is connected in parallel and conducted during running driving, the current stress of each device is small, the running of the motor within a wide rotational-speed range can be achieved by adjusting the excitation current, electromagnetic braking is achieved during braking, and energy is fed back to the battery; and the function of large-power and rapid charging can be achieved during charging running, and the current ripple is small.

A method and system for controlling a power converter system with first, second, and third phase legs with respective first, second, and third associated phase currents determine direction of current flow in at least two phase legs and switch states of the power converter system in response to the current flow directions to reduce ripple current in a connected direct current (DC)-bus capacitor.

The present invention provides a system, apparatus and method for driving a permanent magnet (PM) machine supplied by a Current Source Inverter (CSI). A DC-DC voltage to current converter (chopper) with an inductor value inversely related to the operating frequency of the DC chopper for a given DC Link current ripple, acts as a current source for the CSI. The DC source for the DC-DC voltage to current converter can be from a DC power source or supply, or an AC power source or supply electrically connected to a rectifier/Pulse Width Modulated (PWM) rectifier.

The invention discloses a non-isolation bidirectional high-gain DC/DC converter and a frequency conversion control method, and belongs to non-isolation high-frequency power conversion in power electronic field. The non-isolation bidirectional high-gain DC/DC converter disclosed by the invention comprises a main circuit and a control circuit, wherein the main circuit mainly consists of a low-voltage end V<L>, a high-voltage end V<H>, two inductors (L<1>, L<2>), n+2 MOS transistors (S<1>, S<2>, Q<1>-Q<n>) and n capacitors (C<1>-C<n>), wherein n is cascading quantity. The invention also discloses the frequency conversion control method for the non-isolation bidirectional high-gain DC/DC converter. The switching frequency of the MOS transistors is regulated by the frequency conversion control method, so that current pulsation and ring current loss are reduced of each MOS transistor in the main circuit of the converter under the premise that realization of soft switching is ensured. The non-isolation bidirectional high-gain DC/DC converter and the frequency conversion control method can be widely applicable to storage battery energy storage or a new energy automobile motor driving system.

The invention relates to a DC/DC converter suitable for high-voltage input high-power output, which comprises an input voltage-division circuit formed by serially connecting two input voltage division capacitors, a first resonant converter, a second resonant converter and an output filter capacitor shared by the two resonant converters, wherein the first resonant converter and the second resonant converter adopt an LLC serial resonant circuit; two ends of the first voltage division capacitor are connected with the input end of the first resonant converter, the output end of the first resonant converter is connected with the output filter capacitor; and two ends of the second input voltage division capacitor are connected with the input end of the second resonant converter, and the output end of the second resonant converter is connected with the output filter capacitor. The invention can effectively lower the voltage class of a switching tube and the cost, reduce the switching loss, and can effectively realize static and dynamic flow equalizing property between the two resonant converters, thereby improving the reliability.

The invention discloses a control method for a permanent magnet synchronous motor based on current prediction and belongs to the field of control over permanent magnet synchronous motors. The method mainly comprises the steps of predicting the improved current and identifying the sensorless rotating speed and a corner based on a phase-locked ring idea combined with the predicting step. According to the control method, the current of a motor stator is predicted ahead of a switch period according to the detected current of the motor stator and a current instruction; corresponding control voltage is predicted; and motor rotating speed and corner position information is identified according to the estimated counter electromotive force of the motor. The invention further provides a control system for realizing the control method. The control system comprises a rotating speed regulator, a current predicting unit, a counter electromotive force estimation unit, a controller and a space vector modulating unit. According to the control method and the control system disclosed by the invention, the permanent magnet synchronous motor can be enabled to still safely operate at high efficiency when the parameters change; and the control method and the control system have a favorable application prospect in the field of control over the permanent magnet synchronous motor.

A circuit used to convert a DC input to an AC output comprises a pair of series circuits, one or two capacitors, and one transformer. Each of the series circuits is in parallel with the DC input and comprises a pair of series-connected switches and at least one transformer primary. Each capacitor couples the two series circuits, and is attached to each series circuit at a node between the respective transformer primary and switch. The center nodes between two series-connected switches are connected together. At least one secondary on the transformer provides the AC output. Optionally, multiple transformers may be utilized. Similar topologies may be used for rectification instead of inversion.

The invention provides an AC-DC rectifying device which comprises a PFC power factor correction module, a DC busbar capacitor and a DC-DC convertor module. The DC busbar capacitor is connected in parallel between at least two PFC power factor correction modules in parallel connection and at least two DC-DC convertor modules in parallel connection. In the invention, the PFC power factor correction module and the DC-DC convertor module are connected in parallel, the ripple current of on-off frequency level output by the power factor correction to the DC busbar capacitor is reduced, meanwhile, the ripple current output by the DC busbar capacitor to the DC-DC convertor module is reduced, the heat productivity of the DC busbar capacitor is reduced, the service life of the DC busbar capacitor is prolonged, and the service life of the whole DC-AC rectifying device is further prolonged.

The invention discloses a predictive control method of a fixed-frequency module of a three-phase PWM (pulse-width modulation) rectifier. The predictive control method is characterized by comprising the following steps of: selecting two voltage vectors and a zero vector adjacent to a power grid voltage position angle to serve as action vectors; taking the acquired power grid voltage and input current values under a two-phase rotary coordinate system and voltage values under the two-phase rotary coordinate system corresponding to the selected two voltage vectors and zero vector to serve as input of a current predictive model to as to acquire a change rate of current on d and q axes; and calculating input of the module by adopting the input current value, the reference value of current on the d and q axes and the change rate of current on the d and q axes as vector duration; inputting the action time of each vector into a modulator; and taking the switch position signal as a switch signal for controlling a power device. According to the predictive control method, the system current ripple and current distortion can be effectively reduced, and the operation performance of the model predictive control system can be reinforced.

A power circuit, in certain embodiments, includes an inductor to limit current through a capacitor, wherein the capacitor is configured to smooth ripple for a constant voltage welding system. More specifically, the power circuit may include a rectifier configured to convert AC power to DC power. The rectifier may be coupled to a DC bus configured to transmit the DC power. A capacitive circuit having the capacitor may be coupled across the DC bus to smooth ripple in the DC power. The inductor, e.g., coupled between the DC bus and the capacitive circuit, limits the rate of current flow between the capacitive circuit and the DC bus during a welding operation, thereby reducing heating in the output capacitive circuit. A further inductor may be coupled to one side of the DC bus to stabilize the rate of current flow from the power circuit to a load.

A PFC LED driver capable of reducing current ripple, comprising: a current source unit, having a control terminal coupled to a control voltage, which is a ratio of a full-wave rectified line input voltage, a first channel terminal coupled to a power line, and a second channel terminal used to generate an output current according to the control voltage; and at least one LED load unit, being in series with the current source unit, wherein each of the at least one LED load unit comprises: a first load, including a first parallel combination of an LED module and a capacitor, wherein the LED module has at least one light emitting diode; a diode, being in a first series combination with the first load; and a switch, being in a second parallel combination with the second series combination.

The invention discloses an improved finite set model prediction control method suitable for an inverter. According to the method, the AC bias of current is eliminated by predicting the ripple of the output current and introducing the feedforward link of the current ripple on the basis of finite set model prediction control so that the total harmonic content of the grid-connected inverter output current can be reduced and the quality of electric energy conversion can be effectively enhanced. The improved finite set model prediction control algorithm having universality is researched based on the full-bridge L-type grid-connected inverter so that the total harmonic content of the output current can be effectively reduced on the basis of finite set model prediction control of the single-phase grid-connected inverter. The method can be greatly suitable for application of various finite set model prediction control algorithms on the inverter.