23results about How to "Reduce inrush current" patented technology

The invention discloses an MMC pre-charging method based on bridge arm module alternate bypass. The method comprises the following steps: detecting the voltage of a grid-connected point at the AC side of an MMC; detecting a medium-voltage energy storage unit and a low-voltage energy storage unit, and selecting an energy storage unit participating in MMC pre-charging and a corresponding control mode according to a detection result; controlling a DC bus voltage in the DC power distribution system to be raised to a rated value of a capacitor voltage of an MMC bridge arm sub-module, and executing an MMC pre-charging mode; on the premise that the voltage fluctuation amplitude of the direct-current bus does not exceed the allowable range, different sub-modules on the same bridge arm of the MMC are bypassed alternately in sequence until the difference value between the capacitor voltage of the bridge arm sub-module and the rated working voltage of the bridge arm sub-module is within the allowable range; and closing a circuit breaker at the AC side of the MMC, unlocking the MMC, switching the pre-charging mode of the MMC to a normal operation mode, executing constant DC voltage control by the MMC, and recovering the determined control mode of the energy storage unit to a constant power control mode.

The application discloses a control method and device of an inverter circuit and an inverter system, and belongs to the inverter field. The control method of the inverter circuit comprises the following steps: in the case that a grid performs a grid-connection and off-grid action, the minimum common-mode voltage between the neutral line and the protection ground line on the output side of the inverter is acquired; based on the number of point positions corresponding to the minimum common-mode voltage in the same power frequency cycle and the system delay time length, the target delay time length is determined; the system delay time length is determined based on at least one of the communication delay time length and the mechanical delay time length; after the target delay time length, the relay attraction instruction is issued; the relay attraction instruction is used for instructing the closing of the switching element. The control method of the inverter circuit can reduce the impact current generated in the moment of the closing of the contact, slow down the arc erosion of the relay, and prolong the service life of the relay.

The invention provides a pre-charging circuit of a converter, a control method and a direct-current wind generating set, the pre-charging circuit comprises a switching device and a current limiting device which are connected in series, and the pre-charging circuit is connected to a direct-current switch on a direct-current bus of the converter in parallel, when the switching device is switched on and the direct current switch is switched off, the pre-charging circuit pre-charges the two sides of the direct current switch, so that the difference between the voltages on the two sides of the direct current switch is within a preset difference range. According to the pre-charging circuit of the converter, the control method of the converter, the converter and the direct-current wind generating set disclosed by the invention, the problem that a switch and a device possibly lose efficacy due to impact caused by large voltage difference between voltages at two ends of a direct-current switch in a direct-current power transmission form is solved, and impact current generated when the direct-current switch is closed can be reduced; and the risk that the direct-current switch and related devices are damaged by impact current is reduced.

The utility model relates to the field of switching circuits, in particular to a PMOS (P-channel Metal Oxide Semiconductor) switching circuit, which is characterized in that a source electrode of a PMOS tube Q1 is connected with an input voltage end Vi n, and a drain electrode is connected with a load output end Vout; a base electrode of the triode Q2 receives the switching signal through a control signal end PWR, and an emitting electrode of the triode Q2 is grounded; the first divider resistor R1 is connected between the grid electrode of the PMOS tube Q1 and an input voltage end Vi n; the second divider resistor R2 is connected between the grid electrode of the PMOS tube Q1 and the collector electrode of the triode Q2; the first capacitor C1 is connected between the grid electrode and the source electrode of the PMOS tube Q1; the resistance value ratio of the first divider resistor R1 to the second divider resistor R2 is 1: 3 to 1: 5, the capacitance value of the first capacitor C1 is 10 nF to 100 nF, and the load capacitance C2 does not exceed 470 [mu] F. The voltage division ratio of R1 / R2 is matched with the capacitor C1, so that the conduction time of the PMOS is prolonged, the instantaneous charging current peak value of the load capacitor C2 is remarkably reduced, voltage drop is avoided, and the stability of the system is guaranteed.

The invention discloses a generator core loss test system and method for reducing test impact current, comprising a power supply unit, a switch control unit, a current measuring unit, a voltage measuring unit, a multifunctional power measuring unit, an excitation coil unit, a measuring coil unit and an iron core unit to be tested; the excitation coil unit and the measuring coil unit are wound on the iron core unit to be tested, the power supply unit is connected to the excitation coil unit via the switch control unit, the excitation coil unit is connected to the multifunctional power measuring unit via the current measuring unit, and the measuring coil unit is connected to the multifunctional power measuring unit via the voltage measuring unit. The system and method can effectively reduce the impact current when the switch is closed while saving test costs, reducing workload and shortening test preparation time, thereby greatly improving the economy and safety of the iron loss test.

The present invention provides a voltage regulating device and a mode switching detection circuit thereof. The mode switching detection circuit is used to reset the soft start circuit of the voltage regulating device. The mode switching detection circuit includes a mode switching signal detector, a reset signal generator and a reset state detector. The mode switching signal detector receives the mode switching signal and generates a setting signal according to the transition edge of the mode switching signal. The reset signal generator is coupled to the mode switching signal detector and generates a reset start signal according to the setting signal, wherein the reset start signal drives the soft start circuit to perform a reset action. The reset state detector compares the output voltage of the soft start circuit with a reference voltage to generate a clear signal. The reset signal generator clears the reset start signal according to the clear signal.

The invention provides a converter control method and device, control equipment and a converter, and belongs to the technical field of power supplies. The converter comprises at least two inversion modules; a communication module is arranged between the midpoints of the DC buses of every two adjacent inversion modules, and the communication module comprises a first switch and a first buffer unit which are connected in parallel; the method comprises the following steps: acquiring a midpoint potential of a direct-current bus of each inversion module; for every two adjacent inversion modules, if the midpoint potentials of the DC buses of the two inversion modules are not equal, a first buffer unit between the two inversion modules is controlled to be switched on, and after the first buffer unit is switched on, a first switch between the two inversion modules is controlled to be switched on. According to the method, zero-sequence circulating current between the inversion modules can be avoided, carrier synchronization control in advance in a software control method and strict synchronization of a control process are not needed, and the control process is relatively simple.

The invention discloses an energy storage inverter power grid pre-charging control method and an energy storage inverter system.The energy storage inverter power grid pre-charging control method comprises the steps that when it is detected that no direct-current power source is input into the energy storage inverter system, a pre-charging relay and a first live wire relay are closed, and a direct-current bus of an energy storage inverter is pre-charged through a power grid; the second live wire relay and the null line relay are kept disconnected; when the energy storage inverter meets the pre-charging completion condition, an adjusting loop is started, the adjusting loop is used for enabling the phase difference of the output voltage of the energy storage inverter to be transited to a second angle from a first angle, so that the phase difference of the output voltage of the energy storage inverter is close to the phase difference of the power grid side voltage, and the impact current at the moment of grid connection can be reduced; when the energy storage inverter meets the grid connection condition, the second live wire relay is closed, the pre-charging relay is disconnected, and the zero line relay is closed, so that the energy storage inverter is connected to the grid.

This application relates to the technical field of frequency converters, and in particular to a braking-boost integrated frequency converter and control method for multiplexing switching devices. It includes a rectifier, an inverter, and a DC link, and further includes: a reactor, one end of which is connected to the positive output terminal of the rectifier; a reconfiguration unit, comprising a switching switch, a freewheeling diode, a multiplexing switch, and a braking resistor, wherein the multiplexing switch is connected between the moving end of the switching switch and the negative bus, the switching switch having a first stationary end and a second stationary end, the first stationary end being connected to the other end of the reactor, the anode of the freewheeling diode being connected to the first stationary end, the cathode of the freewheeling diode being connected to the positive bus, and the second stationary end being connected to the positive bus via the braking resistor; and a controller, used to acquire the bus voltage, and when the bus voltage is higher than a preset braking threshold, control the moving end to close to the second stationary end and output a pulse width modulation signal to the multiplexing switch so that the braking resistor and the multiplexing switch form a chopper circuit. This application can solve the defect of easy shoot-through during load switching and achieve safe multiplexing of devices.

The present invention discloses a surge current suppression device, comprising: an AC input port, a load access port, a power supply circuit, a bidirectional thyristor DA, a current limiting resistor RA, a first relay, a thyristor drive circuit and a timing control circuit. After power-on startup, the technical solution uses the thyristor drive circuit to control the conduction moment of the bidirectional thyristor DA, and uses the thyristor drive circuit to set the conduction moment of the bidirectional thyristor DA according to the connected load type, thereby reducing the surge current generated when power is on; the technical solution performs a delay operation after power-on startup, and short-circuits the live input port and the first access port after a first delay period, so that the bidirectional thyristor DA and the current limiting resistor RA are short-circuited, thereby reducing power loss.

The present invention discloses a servo press with a variable moment of inertia flywheel, which relates to the technical field of mechanical transmission press equipment, and includes a fuselage, wherein the fuselage includes an energy storage flywheel mechanism, a main power and crankshaft connecting rod mechanism, a working mechanism, a braking mechanism and a position detection mechanism. The present invention uses the energy storage and release effect of the eccentric variable moment of inertia flywheel. During the operation of the servo press, the eccentric variable moment of inertia flywheel can store energy in the non-working stage. At the critical moment when the crankshaft is about to move to the nominal pressure point, the eccentric variable moment of inertia flywheel uses its stored kinetic energy to automatically decelerate and release the stored energy without the need for additional energy input or consumption, thereby achieving the effect of reducing the installed power of the servo press and improving energy utilization.

The utility model belongs to the technical field of transformers, and provides a transformer switch resistor assembling structure which comprises an anchoring part fixedly connected to the side wall of a transformer body, and the anchoring part is electrically connected with a transformer switch. The switch resistor fixing part is fixedly connected to the side wall of the transformer body through the anchoring part, the switch resistor fixing part is electrically connected with the transformer switch through the anchoring part, the switch resistor fixing part is used for fixedly connecting a plurality of switch resistors, and the switch resistors are electrically connected with the switch resistor fixing part. According to the utility model, the requirement on the installation space can be reduced, and the problems of mutual interference and electrical strength caused by no space when the switch potential resistor is installed at the lower part of the switch can be effectively avoided.

The invention discloses a battery charger and a control circuit thereof, the battery charger comprises a power supply conversion module, a control circuit module and a switching circuit module, the output end of the power supply conversion module is connected with the input end of the switching circuit module, and the output end of the switching circuit module is a battery anode connecting end; the switch circuit module comprises a main switch circuit, an auxiliary switch circuit and a current-limiting resistor, the input end of the main switch circuit is connected with the output end of the power conversion module, the output end of the main switch circuit is connected with the battery anode connecting end, and the driving end of the main switch circuit is connected with the first output end of the control circuit module; the input end of the auxiliary switch circuit is connected with the output end of the power conversion module, the output end of the auxiliary switch circuit is connected with one end of the current-limiting resistor, the other end of the current-limiting resistor is connected with the output end of the main switch circuit, and the driving end of the auxiliary switch circuit is connected with the second output end of the control circuit module; the control circuit module is used for controlling the auxiliary switch circuit to be conducted and controlling the main switch circuit to be conducted so as to reduce charging surge current.

The utility model relates to the technical field of battery charging, and discloses a control circuit for reducing charging surge current, which comprises a power supply unit, a detection unit, a processing unit and a control unit. The detection unit detects the voltage of the battery and feeds back a detection signal to the processing unit, the processing unit outputs a corresponding control signal to the control unit according to the detection signal, and the control unit adjusts the output voltage according to the control signal to enable the output voltage to be the same as the voltage of the battery. And the processing unit controls the switch loop in the power supply unit to be switched on so as to charge the battery. According to the control circuit for reducing the charging surge current disclosed by the utility model, the output voltage and the battery voltage are controlled within a relatively small voltage range, so that the surge current can be reduced to the minimum, and the battery is prevented from being damaged due to the influence of the surge current before being charged.

A DC-DC converter includes a current limiting device and a capacitor. The first interface is coupled to the capacitor and is configured to be coupled to a second interface that supplies an input voltage. The first interface is further configured to couple the input voltage to the capacitor through the current limiting device and then couple the input voltage to the capacitor bypassing the current limiting device. The first interface may include pins of unequal lengths, where a longer pin is connected to the capacitor through a current limiting device and a shorter pin is connected to the capacitor bypassing the current limiting device.

The application relates to an improvement of a MOS tube protection circuit design, in particular to a circuit for reducing the starting impact current of a PMOS tube, after the circuit of the application is added, the impact current flowing through the PMOS tube can be reduced by more than 50%, and the impact current of the PMOS tube is greatly reduced. The circuit comprises a PMOS tube Q1, a base B of a triode Q2, a ground of an emitter E, a connection of a collector C and a resistor R2, a connection of the resistor R2 with a gate G of the PMOS tube Q1 and one end of a resistor R1, a connection of the other end of the resistor R2 with a source S of the PMOS tube Q1, a connection of the source S of the PMOS tube Q1 with an input voltage, a drain D of the PMOS tube for outputting a voltage, and a connection of the output voltage with a filter capacitor C1; and further comprises a PNP triode Q3, an NPN triode Q4, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a capacitor C2 and a diode D1.

The invention relates to the technical field of automobile heat management, in particular to a motor starting method, a controller and a storage medium, the method is applied to the controller, the controller is connected with an electronic control unit of a vehicle, and the vehicle comprises a plurality of liquid control assemblies and a plurality of driving motors connected with the liquid control assemblies. Each liquid control assembly is connected with one driving motor, and the controller is further connected with the multiple driving motors. The method comprises the steps that in response to a received motor starting instruction sent by an electronic control unit, control signals are output to a plurality of driving motors, so that the driving motors are started to work at different moments to drive corresponding liquid control assemblies. According to the method, the multiple driving motors are controlled to start to work at different moments, the surge current is effectively reduced, the situation that the starting current is too large is reduced, and therefore the service life of the controller is prolonged, and the vehicle performance is improved.

The present invention provides a segmented soft start method for a half-bridge series LLC circuit. The method comprises: turning on the first switch tube (Q1) and the third switch tube (Q3), and maintaining operation with a minimum pulse width, so as to load half of the input voltage on the resonant capacitor (Cr) / output capacitor (Co) for continuous charging until the resonant capacitor (Cr) or the output capacitor (Co) is fully charged; switching on the first switch tube (Q1) and the fourth switch tube Q4 and maintaining operation with a minimum pulse width, so as to load the full input voltage on the resonant capacitor (Cr) / output capacitor (Co); adjusting the pulse widths of the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) to a fully open state. The method provided by the present invention can greatly reduce the impact current during the startup process, and there is no phase shift process, so as to avoid voltage imbalance on the first commutation capacitor (C1) and the second commutation capacitor (C2).

The present invention relates to a switching power supply circuit with a long power-off holding time, the circuit comprises a power supply input terminal, a filter capacitor C3, a transformer T1 and a power supply output terminal Vout connected in sequence; the switching power supply circuit also comprises a charging current control module, a charging voltage control module, a power drive module and a delay module, the charging current control module is respectively connected to the power supply input terminal, the charging voltage control module and the power drive module, the power drive module is respectively connected to the charging voltage control module and the delay module, and the delay module is connected in parallel with the filter capacitor C3. Compared with the prior art, the present invention has the advantages of reduced volume and reduced cost.

The utility model provides a soft start circuit and an input circuit of a charging power supply module. The soft start circuit comprises a switch unit, a first resistor, a second resistor and a rectification unit. As the input end of the EMI filter in the charging power supply module is connected to the alternating current power grid through the first switching device, one port of the soft start circuit is connected to the two ends of the first switching device, and the other port is connected with the bus, the charging power supply module can be switched on and off by controlling the switching unit. When the first switching device is disconnected and the EMI filter is disconnected from the power grid, the soft start circuit supplies power to the auxiliary power supply connected with the bus, meanwhile, reactive loss generated by the X capacitor is not introduced, and the stability of the circuit and the signal can be ensured through processing of the first resistor, the second resistor and the rectifying unit; during startup, the switch unit can charge the capacitor in the EMI circuit firstly, so that the impact current of the power grid side is reduced, and the safety of the first switch device is ensured.

The invention provides a control method of a power conversion unit and a power converter. Under the condition that the direct-current capacitor in the power conversion unit is charged, the two ends of the direct-current capacitor are approximately equal to the maximum value of the line voltage between the first phase alternating current and the second phase alternating current, and the amplitudes of the line voltages between any two phases of alternating current are equal, so that under the condition that the direct-current capacitor is charged, the maximum value of the line voltages between the first phase alternating current and the second phase alternating current is equal. The first-phase alternating current is cut out of the power conversion unit, the third-phase alternating current is connected into the power conversion unit, and only small impact current can be caused. Besides, the first phase alternating current is connected to the power conversion unit through the slow start circuit, so that only small impact current is caused, and after the second phase alternating current and the third phase alternating current are directly connected to the power conversion unit, the first phase alternating current is connected to the power conversion unit through the slow start module, and only small impact current is caused. In conclusion, in the power-on process of the power conversion unit, the impact current of the direct-current capacitor is reduced.

The utility model discloses a surge suppression circuit, the circuit is used for suppressing surge current, the circuit comprises an AC power supply and a connection circuit, the connection circuit comprises a bridge rectifier diode, an IC circuit board, a first capacitor, a load device, a relay, a fuse, and a fifth diode. And the output end of the alternating current power supply is used as a starting point of the circuit. The connecting circuit comprises an IC circuit board, the IC circuit board is provided with four connecting ports, a phase line of an alternating current power supply is simultaneously connected with one end of the fuse and an HV port of the IC circuit board, the other end of the fuse is connected with the bridge rectifier diode, a third connecting end of the relay is simultaneously connected with a null line of the alternating current power supply, and a fourth connecting end of the relay is connected with a null line of the alternating current power supply. The relay is controlled by the IC to be closed at the voltage zero crossing point of the alternating current power supply, the voltage difference between the alternating current power supply and the connecting circuit is reduced, the surge current is further reduced, the fuse is prevented from being broken down and the rectifier bridge is prevented from being damaged due to overlarge surge current, and the overall operation reliability of the circuit is further improved.

The invention relates to an inverter grid-connected starting method and related equipment. Wherein the bus input end of the inverter is connected with the direct current power supply, the bus input midpoint of the inverter is connected with the zero line input of the commercial power input through the zero line switch, and the three-phase output end of the inverter is connected with the three-phase input of the commercial power input through the three-phase switch; the method comprises the following steps: when a three-phase switch and a zero line switch are switched off, respectively obtaining first three-phase input parameters corresponding to commercial power input; when the first three-phase input parameter is in a normal range, a zero line switch is closed, so that the bus input midpoint of the inverter is connected with the zero line input of the commercial power input; acquiring a second three-phase input parameter corresponding to the commercial power input and adjusting the working state of the inverter; and when the output parameter corresponding to the three-phase output end of the inverter meets a preset condition, closing the three-phase switch to enable the inverter to complete grid connection. According to the invention, the impact current at the moment of starting grid connection of the inverter can be effectively reduced, and the reliability of a working circuit corresponding to the inverter is improved.