30results about How to "Limit inrush current" patented technology

The embodiment of the invention discloses a slow start circuit and an LED power supply device. The LED power supply device is connected to an LED light string, and the LED power supply device includes a power input circuit, a power control circuit and a slow start circuit; the power input circuit rectifies and filters the mains power Then output the first power supply voltage and the second power supply voltage; the slow start circuit performs internal power supply after stabilizing the first power supply voltage, and outputs a pulse width modulation signal to the power supply control circuit after delaying the preset time when detecting that there is power inside; The power control circuit converts the second power supply voltage into a power supply voltage to supply power to the LED light string according to the pulse width modulation signal, and controls the LED light string to become brighter gradually. The power supply to the LED light string is delayed through the slow start circuit to limit the inrush current when the power is just turned on; the LED light string gradually becomes brighter, so that the eyes can gradually adapt, and the lighting effect is more gentle. Therefore, the problem that the existing LED power supply module cannot be started slowly and lighted at regular intervals is solved.

The invention relates to a switching circuit for an unmanned aerial vehicle. The switching circuit comprises a first switching unit, a current limiting unit, a second switching unit and a delay unit,wherein the input end, control end and output end of the first switching unit are correspondingly connected with an external power supply, a conduction unit and one end of the current limiting unit, the other end of the current limiting unit is connected with a load, the input end, control end and output end of the second switching unit are correspondingly connected with the external power supply,the conduction unit and the input end of the delay unit, and the output end of the delay unit is connected with the load. When the external power supply is required to supply power to the load, the conduction unit is switched on to provide a conduction voltage for the first switching unit and the second switching unit to connect the first switching unit and the second switching unit, the currentlimiting unit exists in a branch circuit where the first switching unit is located to limit a surge current generated immediately when the external power supply is turned on and, meanwhile, the delayunit exists in a branch circuit where the second switching unit is located, connected in parallel with the branch circuit to switch on the branch circuit where the second switching unit is located after a delay. Therefore, an input current is provided for the load after current and voltage stabilization.

A power supply method for seamless switching of motors based on residual voltage estimation: the system adopted in the method includes working and standby power supplies respectively connected to the motor, and a rectifier is connected between the output of the working and standby power supplies, and the rectifier is also connected through an inverter Motor; method: S1, modeling the residual voltage of the induction motor after de-energization; S2, predicting the residual voltage of the motor bus; S3, predicting the initial value of the residual voltage of the bus after the induction motor is de-energized, when the initial value of the residual voltage of the bus is less than the rated voltage of the bus , make sure to start the UPS inverter, so that the UPS inverter is stable in the working state of supplying power to the induction motor; S4, compare the phase of the bus residual voltage with the phase of the backup power supply voltage, and when the phase difference between the two is less than 20°, the backup Power on. The invention can not only provide short-term power supply for important loads when the mains power fails, but also actively adjust the output voltage, quickly switch the standby power supply to avoid impact on the load, and can effectively limit the instantaneous impact current of the standby power supply.

The invention discloses a soft start device and a soft start method of converter equipment, wherein the device comprises a soft start circuit, a current detection device and / or a voltage detection device, the soft start circuit comprises a transformer and a low-voltage switch element, the input end of the transformer is connected with a soft start low-voltage power supply through the low-voltage switch element, and the output end of the transformer is connected with the converter equipment to be used for charging a capacitor of a direct current bus of the converter; the current detection device is connected with the input end or the output end of the transformer for detecting the current of the soft start circuit; and the voltage detection device is arranged on the direct current bus of the converter equipment. The method is based on the device to realize the soft starting of the converter equipment, and comprises the steps of detecting the alternating current network voltage and soft start low-voltage power voltage before the soft starting, prejudging soft start conditions, soft starting, monitoring the charge current and direct current bus voltage states, judging the soft start completing conditions, and finishing the soft starting. The soft start device has small impact to a bus capacitor, safer soft starting, and has small loss and low heat.

The invention discloses a control circuit for a paper shredder. The control circuit for the paper shredder comprises a paper feed detection circuit, a paper shredding delay control circuit, a starting delay control circuit, a feedback control circuit, a triggering control circuit, a switching circuit, a power circuit and a motor, wherein the paper feed detection circuit is used for detecting whether paper is placed into a paper shredding opening of the paper shredder or not; the paper shredding delay control circuit and the starting delay control circuit are used for controlling the stopping work delay time and the starting work delay time by changing the resistance value and the capacitance; the feedback control circuit is used for providing positive feedback for the starting delay control circuit; the triggering control circuit is used for controlling on-off of the switching circuit; the switching circuit is used for controlling the motor to operate or stop; the power circuit is used for supplying power to the other circuits of the paper shredder; and the motor is used for driving the paper shredder. According to the control circuit for the paper shredder, the paper shredding delay control circuit and the starting delay control circuit are arranged, the paper shredder can still work for a period of time after the tail of paper leaves the paper shredding opening, or the paper shredder can be stopped and then operate again under the condition that the tail of the paper is not completely shredded after paper-jam stopping caused by too much paper, and thus the paper can be completely shredded.

The invention relates to a power converter, which is composed of three bridge arms connected in parallel and then connected in parallel with a working capacitor; and between the midpoints of the first bridge arm and the second bridge arm, there is a commercial power input and an inductance connected in series, and the second bridge arm The primary side of the transformer is connected in series between the midpoint of the arm and the third bridge arm, and the negative side of the transformer is connected to the DC output circuit; the control terminals of the first bridge arm, the second bridge arm, and the third bridge arm are all connected to the control circuit The control signal is connected; wherein the control circuit selectively controls the conduction of the switch tube corresponding to the first bridge arm and the second bridge arm according to the detection result of the zero-crossing voltage input by the mains to perform power factor correction. The control circuit also detects the load The operating state parameters selectively control the conduction of the switch tube of the third bridge arm to output energy to the secondary side of the transformer so that the DC output circuit outputs DC; the present invention combines AC anti-surge, rectification and filtering, PFC conversion, DC / The DC is designed together, and only six switching tubes are used to complete the power conversion.

The invention discloses an input and output protection circuit of a vehicle-mounted DC converter, which comprises: an input and output switch arranged at the input end and / or the output end of the vehicle-mounted DC converter; a fuse and a first capacitor respectively connected with the input and output switches; a power supply battery connected; and a soft start circuit respectively connected with the first capacitor and the power supply battery, which together with the power supply battery, the fuse, the input and output switches and the first capacitor form a series circuit. By connecting the soft-start circuit, the present invention can perform current limiting protection on the entire circuit, avoid the defects of damage or life loss of components in the circuit caused by large inrush current when starting or shutting down the vehicle-mounted DC converter, and reduce the The failure rate and maintenance cost of the whole vehicle are reduced, and the reliability of the whole vehicle is improved. In addition, the present invention also provides an input and output protection method of a vehicle-mounted DC converter and an electric vehicle.

The invention provides a high-voltage battery discharge circuit and control method thereof, and belongs to the technical field of high-voltage battery solving the problem of poor safety in the prior art. The control method for the discharge circuit of the high-voltage battery comprises the following steps of: detecting whether the two ends of the capacitive load C1 are showed voltage, if so, recording the fault state as error I and alarming; if no voltage is showed, the pre-charging contactor K1 and the pre-charging contactor K4 are controlled to be closed simultaneously, detecting the voltageon the two ends of the capacitive load C1 in the suction process and recording the pre-charging time, and calculating the real-time rising rate of voltage on the two ends of the capacitive load C1 inthe unit time; if the rising rate is not within a preset range value, recording the fault state as an error II and alarming; If the rising rate is within a preset range value, the negative contactorK3 and the positive contactor K2 are controlled to be closed, the pre-charging contactor K1 and the pre-charging contactor K4 are disconnected, and the high-voltage battery discharging circuit entersa safe working mode. The high-voltage battery discharge circuit can improve the safety of the high-voltage battery.

The invention provides an isolated type LED light fixture adjustable light power supply. An input terminal of the power supply is connected into a silicon control light modulator, and an output terminal of the power supply is connected into an LED load. Through an operation of the silicon control light modulator by a user, a drive circuit of the power supply can be controlled, an average value of driving circuit input voltage and current of a driving circuit output terminal are changed, and a purpose of brightness control and adjustment of the LED load is realized. The power supply is characterized in that: a circuit of the power supply comprises and EMI filter circuit, a bridge rectifier filter circuit, a pre-stage LC filter circuit, an input voltage buffer circuit, a transformer, an output circuit, a controllable silicon current loop holding circuit, a light regulating voltage detection circuit, a switching frequency set circuit, a light regulating driver chip, an overcurrent detection absorption circuit, an LED current detection circuit, a chip power supply circuit, and an input current detection circuit. The power supply can be compatible with a silicon control light modulator on the market. The power supply driving circuit has good safety performance and can effectively limit surge current, the LED load is more stable in working condition, and higher working efficiency is ensured.

The invention provides a relay protection circuit, including a control module and a conversion module, the control module includes a window unit, a first drive unit and a second drive unit; the conversion module includes a first conversion unit, a second conversion unit and The third conversion unit, the first drive unit includes a first drive speed control module and a relay drive module, the first drive speed control module outputs the first control signal to the relay of the first conversion unit by controlling the relay drive module; the second drive unit includes The second drive speed control module and the PFC drive module, the second drive speed control module outputs the second control signal to the PFC switch module of the second conversion unit by controlling the PFC drive module; the input end of the first conversion unit is connected to one end of the window unit The other end of the window unit outputs control signals to the first drive speed control module and the second drive speed control module. The improved circuit can limit the start-up inrush current and improve product reliability.

The invention relates to a shore power supply system. The shore power supply system comprises a shower power grid, a variable-frequency power source, a grid-connection switch, a generator switch and a ship power generation system. The variable-frequency power source comprises a multi-winding transformer and at least one power source module, the input side of each power source module is connected with a low-voltage side winding of the multi-winding transformer, and the output sides of the power source modules are in cascade connection. Each power source module comprises a rectification unit and an inverter unit, and further comprises a high-speed switch, an absorption resistor and a bypass switch, wherein the high-speed switch is connected with the absorption resistor in series, the series connection part is further connected with a direct current output side of the rectification unit in parallel, and the bypass switch is connected with the output side of the inverter unit in parallel. The invention further comprises a grid-connection control method of the shore power supply system. A reverse-power phenomenon is prevented from occurring to the ship power generation system, the success rate of grid connection is greatly improved, and the system is safe, reliable and low in cost.

A power-on surge current suppression circuit applied to a switching power supply is disclosed. The power-on surge current suppression circuit comprises an optional small-capacity filter capacitor C, an N-channel MOS tube Q, a current suppression resistor R, an outage leakage circuit, a rectifying filtering amplitude-limiting circuit and a power supply winding; the two ends of the current suppression resistor R are connected with the drain electrode and the source electrode of the N-channel MOS tube Q; the outage leakage circuit is connected between the grid electrode and the source electrode of the N-channel MOS tube Q; the rectifying filtering amplitude-limiting circuit and the power supply winding are serially connected and then connected between the grid electrode and the source electrode of the N-channel MOS tube Q; the drain electrode and the source electrode of the N-channel MOS tube Q are serially connected between a power frequency rectifier and a DC-DC converter; and the optional small-capacity filter capacitor C is connected between the positive end and the negative end of the power frequency rectifier. The surge current in the power-on moment is limited by the power-on surge current suppression circuit; the MOS tube is low in power consumption and high in starting speed; and the power-on surge current suppression circuit is short in time for allowing re-power-on.