299 results about "Surge voltage" patented technology

Disclosed in the present application are a silicon carbide MOSFET device and a manufacturing method therefor. The silicon carbide MOSFET is provided with a first withstand voltage masking structure and a second withstand voltage masking structure. The withstand voltage performance of the device is improved, the breakdown problem of a gate insulating dielectric layer can be avoided, the electrostatic effect of the device on a severe environment and the high-voltage peak tolerance capability in the circuit are improved, and the surge voltage resistance of the device and the over-voltage protection capability are improved. Ion implantation can be carried out on a first trench to form the first withstand voltage masking structure, and ion implantation can be carried out on a second trench to form the second withstand voltage masking structure.

The invention discloses a surge protection circuit, which belongs to the field of semiconductor surge protection devices, and comprises a plurality of resistors, a plurality of voltage stabilizing diodes and a plurality of transistors, the first end of the first resistor is connected with a bus voltage, the first end of the first transistor and the second end of the second transistor; the second end of the first resistor is connected with the third end of the first transistor and the cathode of the first Zener diode, and the anode of the first Zener diode is connected with the cathode of the second Zener diode and the third end of the third transistor. The anode of the second voltage stabilizing diode is connected with the second end of the third resistor, the second end of the third transistor, the first end of the second transistor and the ground, the second end of the first transistor is connected with the first end of the second resistor, and the second end of the second resistor is connected with the first end of the third resistor, the first end of the third transistor and the third end of the second transistor. According to the invention, the problems of surge voltage such as electrostatic discharge, electrical fast transient pulse train, lightning stroke, peak and the like, transient voltage generated in a hot plug process and the like can be solved.

The utility model relates to a lightning protection and insulation withstand voltage protection circuit, which is characterized in that a circuit is formed by piezoresistors MOV1, MOV2, MOV3 and MOV4, when surge voltage such as lightning stroke and the like exceeds rated voltage, the values of the piezoresistors in a parallel circuit are suddenly reduced to be conducted, high voltage passes through gas discharge tubes G1 and G2, and after lightning transient overvoltage is discharged, the circuit is discharged by a grounding wire. Meanwhile, the resistance value of a piezoresistor MOV5 connected in the LN circuit in parallel is sharply reduced to be switched on, and a fuse Ft is burnt out by instantaneous strong current, so that electric equipment such as an LED power supply and the like is prevented from being damaged. In addition, the technical scheme has a protection mode of lightning protection and discharge resistor combination of resistors R1, R2 and R3, can meet the requirements of lightning protection and high voltage, has the characteristics of no leakage current, no follow current and the like, and effectively prolongs the service life of an LED system.

The invention provides an anti-surge-voltage planar gate silicon carbide VDMOS and a preparation method thereof, and the method comprises the steps: depositing metal on the lower side surface of a silicon carbide substrate, and forming a drain metal layer; epitaxially growing on the upper side surface of the silicon carbide substrate to form a drift layer; forming a barrier layer on the drift layer, and performing etching and ion implantation to form a protection region, a current sharing region, a second P-type well region, a Schottky region, a first P-type well region and a lug boss; a barrier layer is formed again, etching and ion implantation are carried out, and an N-type source region is formed; forming a barrier layer again, etching and depositing to form an insulating medium layer; forming a barrier layer again, etching and depositing metal, and forming a gate metal layer; the method comprises the following steps: preparing a source electrode metal layer, re-forming a barrier layer, etching, depositing metal, forming a source electrode metal layer, removing the barrier layer, and completing preparation. The reliability of the device is improved, the conduction loss of the device is reduced, and the surge voltage resistance is improved.

The invention relates to an equivalent modeling method and system for an impulse voltage disturbance source in a immunity test, and the method comprises the steps: building an equivalent circuit model of a static gun according to a static gun equivalent circuit in combination with SPICE simulation optimization, and in combination with the overall structure of the static gun used by a human body; the method comprises the following steps: constructing an equivalent circuit model of an electrical fast pulse train based on a circuit structure suggested by an electrical fast pulse train immunity test standard in combination with SPICE simulation optimization; a combined wave circuit is analyzed by adopting an SPICE tool, a surge combined wave generator circuit model is constructed by adopting a step voltage source on the basis of an original circuit model in combination with circuit parameters, and an impulse voltage disturbance source in an immunity test is realized based on the three models. By constructing the equivalent circuit model of the electrostatic gun, the equivalent circuit model of the electrical fast pulse train and the circuit model of the surge combination wave generator, the protection performance of the electromagnetic protection device under the surge voltage disturbance source is simulated and tested, and the anti-interference performance of protection measures is accurately predicted and evaluated.

The utility model relates to an H-bridge driving circuit with a discharge branch and a chip, and belongs to the field of motor driving. The driving circuit comprises a driving chip module, a switch control module and a switch misconduction protection module. The switch control module is composed of a triode and MOS tube combined control circuit, it is ensured that grid charges can be rapidly discharged when the IGBT is turned off, and misconduction is prevented. The misconduction protection module enhances the charge discharge capability by providing a low-impedance path, ensures the accurate turn-off of the IGBT, and avoids the influence of surge voltage. The circuit realizes reliability and quick response performance in forward and reverse control and high-frequency switch application of the motor, and is suitable for direct-current motor control, stepping motor control, direct-current-alternating-current converters, direct-current-direct-current converters and other power electronic devices. Through the design, the stability and the safety of the motor control system are effectively improved.

To address a problem in a connection change of wiring corresponding to test items taking a long time, the connection change causing a surge voltage and an inrush current, resulting in difficulty in accurately measuring changes in transistor characteristics.SOLUTION: A switch circuit board 201b is provided with a switch circuit 124a. A switch circuit board 201a is provided with a switch circuit 124b. A plurality of switch circuit boards 201b are disposed in parallel, and a conductive plate 204 has portions protruding from the switch circuit board 201b. A wire 211 is connected to a device terminal of a transistor 117 to be tested and the protruding portion of the conductive plate 204 of a selected switch circuit board 201b. The switch circuit 124b is disposed between output terminals of a power source circuit 121, and when turned on, shorts the output terminals. The switch circuit 124a is disposed between the output terminal of the power source circuit 121 and the device terminal of the transistor 117 to be tested, and when turned on, supplies a test current to the transistor 117.SELECTED DRAWING: Figure 14

This application discloses a silicon carbide MOSFET device and its fabrication method. The silicon carbide MOSFET has a first withstand voltage masking structure and a second withstand voltage masking structure, which improves the withstand voltage performance of the device, avoids the problem of gate insulating dielectric layer breakdown, improves the device's resistance to electrostatic effects in harsh environments and high voltage spikes in the circuit, and improves the device's surge voltage resistance and overvoltage protection capability. Furthermore, the first withstand voltage masking structure can be formed by ion implantation based on the first trench, and the second withstand voltage masking structure can be formed by ion implantation through the second trench. A large depth of ion implantation region in the silicon carbide epitaxial layer can be achieved without high-dose, high-energy ion implantation. The fabrication process is simple and the fabrication cost is low.

Embodiments of the present application relate to the technical field of circuits, and provide a boost circuit and an electronic device, which can solve the problem of a device being easily damaged in a surge voltage scenario. The boost circuit comprises: a first inductor and a second inductor; at least two first switch transistors, which are sequentially connected in series between a second end of the second inductor and a positive electrode of a busbar; at least two second switch transistors, which are sequentially connected in series between the second end of the second inductor and a negative electrode of the busbar; and a first capacitor which is electrically connected between a first node and a corresponding second node. At least one of the at least two first switch transistors and the at least two second switch transistors is connected in parallel with a corresponding variable resistor device, the variable resistor device being a device which changes from a high resistance state to a conducting state when the voltage difference between two ends exceeds a voltage threshold. The at least two first switch transistors and the at least two second switch transistors are used for cutting off when a current on the first inductor exceeds a current threshold.

The invention discloses an OLTC topological structure of an electronic soft switching technology and a driving method. In the topological structure, a power supply is connected with a first transformer, the first transformer is connected with a second transformer, and the second transformer is connected with a load; a low-voltage winding of the first transformer is connected with a plurality of taps; the fixed end of the low-voltage winding of the first transformer and each tap are connected with one end of an independent mechanical switch; according to an interval connection mode, the other ends of all the mechanical switches are connected to form two series switch loops, and each series switch loop is connected with an independent electronic change-over switch to form two series circuits; the two electronic change-over switches are connected in parallel, and the second transformer is connected into a series circuit controlled by the two electronic change-over switches respectively. The mechanical switch and the electronic change-over switch are jointly used, so that short-circuit current and surge voltage cannot be generated when the electronic change-over switch performs state switching, and the quality of output voltage waveforms is improved.

The embodiment of the utility model discloses a lightning stroke surge protection circuit and a circuit board, and relates to the field of protection circuits, and the lightning stroke surge protection circuit comprises a lightning stroke surge protection module, a rectification filtering module, a residual voltage protection module and a load module. Wherein the power supply input end is connected with the input end of the lightning stroke surge protection module, the output end of the lightning stroke surge protection module is connected with the input end of the rectification filtering module, and the lightning stroke surge protection module absorbs lightning stroke surge voltage input from the power supply input end to obtain first reduced voltage; the first step-down voltage is transmitted to the rectification filtering module through the output end of the lightning stroke surge protection module. By adopting the embodiment of the invention, a good protection effect can be provided when lightning surge occurs in the circuit, and the accuracy is higher.

The invention relates to the technical field of power electronics, and discloses a surge voltage suppression system and a control method thereof. The system comprises a surge feature extraction unit, a suppression map generation unit, a strategy deduction and check unit and an instruction synthesis and distribution unit which are connected in sequence. According to the method, surge feature descriptors are extracted and fused with a historical case library and a real-time power grid topology, and a suppression atlas containing multi-path parameter combination is dynamically generated; and performing time sequence deduction and interaction influence calculation on each path in the map, iteratively correcting parameters to output a checked strategy sequence, and finally converting the strategy sequence into an instruction to control the action of the physical suppression equipment. According to the method, the whole process of the suppression strategy from historical experience learning, dynamic generation to global collaborative rehearsal optimization is realized, and the adaptability, the collaboration and the reliability of responding to surges in a complex power grid environment are improved.

The invention relates to a surge protection device and a vehicle, and the device comprises a detection module of which the input end is used for accessing a power supply voltage signal and is connected with a load power supply end through a power harness, and which is configured to output a first detection signal when detecting that a surge voltage signal exists in the power harness based on a comparison result of a reference voltage signal and the power supply voltage signal; the first end of the switch module is connected with the output end of the detection module, and the switch module is switched off according to the first detection signal; the first input end of the protection module is connected with the input end of the detection module, the second input end of the protection module is connected with the second end of the switch module, the output end of the protection module is connected with the load power supply end, and the protection module is configured to respond to turn-off of the switch module and control connection between the first input end and the output end of the protection module based on a surge voltage signal. A voltage signal which is output to a load power supply end through an output end of the clamp is clamped in a safe voltage range; therefore, safe and reliable surge protection can be carried out on the power supply loop.

The utility model relates to the technical field of electrical protection devices, in particular to a surge protection device with a temporary overvoltage protection function, which comprises a piezoresistor assembly, an inductor and a switch assembly, the piezoresistor assembly is connected with the switch assembly in parallel, and two ends of the inductor are respectively connected with the piezoresistor assembly and the switch assembly. The switch assembly comprises a conduction switch, a combination switch, a resistor R1 and a capacitor, the conduction switch is in linkage connection with the combination switch, the conduction switch is connected with the capacitor in series, the resistor R1 is connected with the combination switch and the inductor in series, and one end, away from the conduction switch, of the capacitor is connected with the combination switch and the piezoresistor assembly; when the conduction switch is closed and the capacitor is fully charged, the combination switch is conducted. By means of the arrangement, the surge protection device can be prevented from being damaged by impact when overvoltage occurs; when surge voltage occurs, the surge protection device can effectively discharge the surge voltage, and the safety of electric equipment is protected.

The invention discloses a closed-loop control surge suppression circuit based on an NMOS tube, and belongs to the technical field of power electronics, the circuit is bridged between a power supply and a load, the protection threshold of surge voltage is changed by adjusting the resistance value of a resistor, and when the surge voltage in the power supply exceeds the protection threshold, the surge suppression circuit is turned off. The output voltage is changed through closed-loop control of an NMOS tube in the voltage division suppression sub-circuit, and then the working state of the closed-loop control surge suppression circuit based on the NMOS tube is adjusted to suppress the surge voltage. The boost circuit is introduced into the power supply sub-circuit, and the output end of the boost circuit is connected with the second end of the fourth resistor and the second end of the second resistor in the feedback control sub-circuit, so that closed-loop feedback is completed by taking an NMOS tube as a core and utilizing discrete devices which are relatively low in cost and easy to obtain, and a protection threshold value of surge voltage can be accurately set by adjusting reference voltage; and the voltage higher than the protection threshold is clamped, so that the voltage on the load is not higher than the protection threshold to protect the load.

The utility model relates to the technical field of charging systems, and belongs to an OBC surge voltage protection circuit, which is characterized by comprising a power grid voltage sampling and diagnosing circuit and a switch control circuit connected with the power grid voltage sampling and diagnosing circuit and used for controlling on-off of an input power grid, and the front section of the power grid voltage sampling and diagnosing circuit is connected with a power grid live wire L and a zero wire N; the rear end of the switch control circuit is connected with a rectifier bridge BD1, the rectifier bridge BD1 is connected to an output ground PGND, and the power grid voltage sampling and diagnosis circuit comprises a sampling circuit module used for sampling power grid voltage, a diagnosis circuit module used for diagnosing the power grid voltage and a latch circuit module used for outputting surge voltage protection signals. An RC filtering circuit module is arranged between the voltage diagnosis circuit module and the latch circuit module, and the surge voltage protection signal is connected to the switch control circuit. According to the utility model, the timely diagnosis of the surge voltage can be realized through the network voltage sampling and diagnosis line, and the switch control line is used for quickly disconnecting the power grid, so that the damage of internal devices of the OBC is effectively avoided, the protection of the surge voltage is realized, the stability of the OBC circuit is improved, and the service life of the OBC circuit is prolonged.

The invention discloses an electrostatic discharge circuit and a radio frequency front-end module. The electrostatic discharge circuit comprises a trigger module, a discharge module and a control module. The trigger module comprises a first resistor and a capacitor. The discharge module comprises a first phase inverter and a first switch tube, the input end of the first phase inverter is connected to the common end of the first resistor and the capacitor, and the output end of the first phase inverter is connected to the control end of the first switch tube. The control module comprises a detection unit and a control unit, the detection unit is used for outputting a detection signal when the power supply end is in a power-on state, and the control unit is used for controlling the first resistor to be in a short-circuit state or / and controlling the capacitor to be in an open-circuit state when the detection signal is received. The first resistor and the capacitor cannot form an RC trigger, so that the situation that the surge voltage in the power supply voltage mistakenly conducts the first switch tube can be avoided, and the anti-surge capability of the electrostatic discharge circuit is improved.

The utility model discloses a circuit capable of inhibiting surge voltage between contacts when a relay acts. The circuit comprises a relay, a resistor, a piezoresistor, a diode, a direct current electromagnetic coil and a binding post. When a high-capacity inductive load in a circuit loses power, a relatively high reverse electromotive force, namely a surge voltage, is generated. A resistor-diode series follow current loop and a piezoresistor-diode series surge suppression loop are reversely connected in parallel to the two ends of an inductive load, when the load loses power and generates reverse electromotive force, the follow current loop eliminates or reduces the electromotive force, and the surge suppression loop is conducted and shunted when the electromotive force exceeds a threshold value, so that surge voltage is prevented from being generated through dual protection; and a relay contact and a circuit are protected. The scheme is a passive suppression protection circuit, has the advantages of simple structure, low cost, fast response, recoverability, dual protection and the like, and improves the operation stability and reliability of equipment.

To suppress the surge voltage of the first surge voltage caused by square waves and the second surge voltage caused by harmonic frequency components, to broaden the frequency characteristics of the output of the switching amplifier and to make the output frequency variable.SOLUTION: A switching amplifier in push-pull configuration with narrow bandwidth filter on the output side comprises a partial resonance circuit to suppress the first surge voltage caused by square waves and a LCR series resonator to suppress the second surge voltage caused by harmonic frequency components, and the waveform shape of the drain-source voltage Vds of the switching element is a trapezoidal waveform.SELECTED DRAWING: Figure 1

The invention belongs to the technical field of emergency protection devices, and particularly relates to a circuit emergency protection device and a method thereof.The device comprises a wiring base, a normally-closed single-pole double-throw relay detachably arranged on the front end face of the wiring base, and a surge protection module arranged on the lower portion of the front end face of the wiring base; a mounting groove is formed in the front end surface of the wiring base, and the surge protection module is detachably arranged in the mounting groove; the device further comprises a separation module arranged in the installation groove and used for being triggered when the surge protection module breaks down and is short-circuited, and separation operation of the surge protection module and the installation groove is achieved. In the actual working process, overload or surge voltage can be released through the surge protection module so as to protect the load, and if continuous fault overload voltage occurs, the surge protection module breaks down and is short-circuited, and then the temperature continuously rises to cause a fire disaster. Therefore, the surge protection module can be separated from the mounting groove through the separation operation executed by the separation module so as to realize forced disconnection.

The invention relates to the technical field of automobile standby power supplies, in particular to a surge absorption device for an automobile standby power supply. Comprising a super-capacity module unit, a bypass switch and a diode, the super-capacity module unit is connected with the standby power supply in parallel, and the positive electrode of the super-capacity module unit is connected with the positive electrode of the standby power supply; after the bypass switch is connected with the diode in parallel, one end is connected with the positive electrode of the super-capacitance module unit and the positive electrode of the standby power supply, and the other end is connected with the positive electrode of the charge-discharge motor as a surge protection port; the negative electrode of the super-capacity module unit is grounded and connected with the negative electrode of the charging and discharging machine; the cathode of the diode is connected with the anode of the super-capacitance module unit. The surge current of the standby power supply is absorbed in a mode of combining the fast recovery diode and the super module, and the surge voltage value range is ensured to be within the designed tolerance range by adjusting the initial voltage of the super-capacity module, so that the standby power supply is not damaged, and the test on the surge voltage tolerance of the standby power supply is not reduced; and the test efficiency is improved.

The utility model discloses a surge protection circuit, a controller, a battery management system, power distribution equipment and a vehicle. The surge protection circuit comprises a first transient voltage suppressor diode and a second transient voltage suppressor diode, the anode of the first transient voltage suppressor diode is connected with the anode of the second transient voltage suppressor diode, and the cathode of the first transient voltage suppressor diode is suitable for being connected with the anode end of a power supply. The cathode of the second transient voltage suppression diode is suitable for being connected with the negative terminal of the power supply and the first grounding terminal. According to the surge protection circuit, when a positive surge occurs and the first transient voltage suppressor diode is broken down, the second transient voltage suppressor diode can serve as a common diode to be conducted, surge voltage is discharged from the first grounding end, and when a negative surge occurs and the second transient voltage suppressor diode is broken down, the surge voltage is discharged from the second grounding end. And the first transient voltage suppression diode can be conducted as a common diode, so that the surge resistance of a subsequent circuit can be improved.

The application provides a voltage stabilizing circuit, a motor control circuit, a motor and an electrical appliance. The voltage stabilizing circuit is used for stabilizing a working circuit, and comprises: an energy processing unit connected in parallel with the working circuit and capable of stabilizing the working circuit; a switching unit connected between the working circuit and the energy processing unit and used for controlling the on-off of the energy processing unit and the working circuit; and a control unit connected with the switching unit and used for controlling the state of the switching unit according to the output power of the working circuit, so that the energy processing unit is connected to or disconnected from the working circuit. The voltage stabilizing circuit has the functions of power factor correction and surge voltage absorption, and can also maintain the minimum value of the bus voltage.

The utility model discloses a voltage surge generation circuit, include: auxiliary source subcircuit, monostable subcircuit and external power supply switching subcircuit, auxiliary source subcircuit is used for the power supply of monostable subcircuit, monostable subcircuit is used for through the timer output high level time of configuration self, to output control signal, external power supply switching subcircuit is used for under the control of control signal output corresponding surge voltage. The utility model discloses utilize auxiliary source subcircuit, monostable subcircuit and external power supply switching subcircuit composition voltage surge generation circuit, has realized the generation of surge voltage, compared with the existing surge generator has simple structure, response speed is fast and the characteristics of high reliability. Further, can edit the timer peripheral circuit in monostable subcircuit according to actual needs, to control the pulse width of surge voltage, adjusts the surge voltage of external power supply voltage output different voltage grade.

The invention provides a rapid flexible switching method for a permanent magnet synchronous motor winding reconstruction circuit, and belongs to the technical field of permanent magnet synchronous motor winding reconstruction. In order to solve the problems of surge voltage, impact current, torque drop and even torque interruption generated in a motor winding reconstruction transient state and relatively long transient state reconstruction time in an existing permanent magnet synchronous motor winding reconstruction method, the method comprises the following steps: step 1, in a zero vector interval of space vector pulse width modulation, carrying out space vector pulse width modulation; the permanent magnet synchronous motor winding reconstruction circuit enters a reconstruction transient state; 2, forming three different natural follow current loops of a mode 1, a mode 2 and a mode 3 by utilizing the combination of the switching states of the motor winding, the inverter, the series reconfiguration switch and the parallel reconfiguration switch, and adjusting the length of a zero vector interval required by winding reconfiguration according to the operation condition; and step 3, completing all reconstruction transient states in a zero vector interval of space vector pulse width modulation, and realizing switching of motor winding connection modes.

The utility model relates to an anti-surge circuit and an energy storage system. The anti-surge circuit comprises an energy storage starting unit, a main circuit switch unit, a surge switch unit, a primary anti-surge unit and a secondary anti-surge unit. Wherein the energy storage starting unit is used for controlling the conduction of the main circuit switch unit when an input power supply is connected, so as to connect a path between the input power supply and a load through the main circuit switch unit. In the process of connecting the path through the main circuit switch unit, if the input voltage of the input power supply is between a first voltage value and a second voltage value, the first-stage anti-surge unit is controlled to be switched on through the first surge voltage at the first connecting part, so that the first surge voltage is absorbed through the first-stage anti-surge unit; the surge switch unit is controlled to be switched on through the first surge voltage, so that the main circuit switch unit is switched off; and if the input voltage is greater than the second voltage value, a second surge voltage at the first connection part is absorbed through the second-stage anti-surge unit. By adopting the anti-surge circuit, the safety can be improved.

The first surge voltage caused by a square wave and the second surge voltage caused by a harmonic frequency component are suppressed, and the frequency characteristic of the output of the switching amplifier is made broadband and the output frequency is made variable. [Solution] A switching amplifier having a push-pull configuration with a narrow-band filter on the output side is provided with a partial resonant circuit that suppresses a first surge voltage caused by a square wave and an LCR series resonant element that suppresses a second surge voltage caused by a harmonic frequency component, and the waveform shape of the drain-source voltage Vds of the switching element is made trapezoidal.

Disclosed in the present application are a varistor mounting structure and an electrical connection device, the electrical connection device comprising a power supply line (100) and a detection and protection apparatus provided on a circuit board and electrically connected to the power supply line (100). The detection and protection apparatus comprises a trip coil (Lx) for generating an electromagnetic force to disconnect an electrical connection, and a first varistor (ZR1) for absorbing a surge voltage. A support frame (400) for fixing the trip coil (Lx) is provided on the circuit board, and a first mounting portion (410) for mounting the first varistor (ZR1) is provided on the support frame (400). The first mounting portion (410) is provided with a first mounting hole (411) and a second mounting hole (412) for two pins of the first varistor (ZR1) to pass through respectively, and an isolation portion (413) for increasing a creepage distance is provided between the first mounting hole (411) and the second mounting hole (412).

The invention belongs to the technical field of aircraft control, and particularly discloses an airborne power supply control system and method, and the method comprises the steps: a protection circuit achieves the power supply overcurrent protection, surge current suppression protection and surge voltage protection of an input aircraft power supply, and transmits the power supply overcurrent protection, surge current suppression protection and surge voltage protection to a filter circuit; the filter circuit carries out electromagnetic interference filtering on the input airplane power supply and sends the electromagnetic interference to the power supply interruption detection circuit, the power supply control circuit and the energy storage circuit respectively; when the power supply of the aircraft is cut off instantaneously, the energy storage circuit continues to supply power to the flight control equipment to enable the flight control equipment to work normally. The power supply interruption detection circuit detects the working state of an aircraft power supply in real time, and sends power supply interruption information to the flight control equipment when detecting that the aircraft power supply has power supply transient interruption; and after receiving the power supply interruption information, the flight control equipment controls the power supply control circuit to cut off the power supply of the aircraft power supply to other equipment, and controls the aircraft power supply to supply power to other equipment again after a preset time is delayed.

A gate driving device is provided, which can simultaneously suppress a turn-off surge voltage and reduce a switching loss by changing a switching speed at an appropriate timing. The gate driving device comprises: a gate driving unit that drives a gate of a switching element according to an input signal that instructs the switching element to turn on or off; a timing determination unit that measures an on-time width from when the input signal switches to an on-command to when it switches to an off-command, and determines a mid-time timing before the turn-off surge voltage of the switching element reaches a peak value based on the measured on-time width; and a driving condition changing unit that changes a gate driving condition of the switching element at the mid-time determined by the timing determination unit.