798 results about "Overcurrent" patented technology

The invention discloses a CPLD-driven IGBT short-circuit current dynamic monitoring method and system, and relates to the technical field of power electronics, and the method comprises the specific steps of S100 real-time data acquisition, S200 dynamic threshold calculation, S300 short-circuit state judgment, S400 rapid protection execution, and S500 fault data recording and uploading. Accurate and prospective judgment of the short circuit state of the IGBT is achieved, two stress parameters including the direct-current bus voltage and the junction temperature serve as independent variables, when the bus voltage rises, the voltage stress borne by the IGBT in the turn-off period is increased, meanwhile, the current peak at the short circuit moment is more remarkable, early warning is conducted in advance by dynamically lowering the threshold value, and therefore the short circuit state of the IGBT is accurately judged. According to the mechanism, the monitoring system does not simply respond to the occurred overcurrent, but can pre-judge the safety boundary of the device under the current working condition, so that intervention is implemented before the current really reaches a dangerous peak value, and a protection blind area under a severe working condition is effectively avoided.

A low voltage ride through control method for a grid-forming inverter based on dynamic internal potential adjustment comprises the following steps: detecting a voltage per unit value of a grid-connected point in real time, and comparing the voltage per unit value with a threshold value to judge a voltage drop event and trigger low voltage ride through control; dynamically calculating active and reactive power reference values through a reactive compensation equation and an active current limiting equation according to the voltage amplitude and the power reference value before falling during the ride-through period; inputting the active reference value into a virtual rotor motion equation to generate a reference phase, and outputting a phase reference signal in combination with a dual-mode phase compensation controller; superposing the reactive reference value with the reference voltage through a reactive voltage regulating ring to generate a voltage amplitude reference signal; synthesizing an internal potential according to the phase and the amplitude reference signal, and obtaining an inductive current reference value through virtual impedance control and current amplitude limiting; and finally, a driving signal is generated through the current inner loop controller and the modulation module. According to the invention, overcurrent can be effectively inhibited, rapid reactive power support is provided, and synchronous stability and smooth transition in a fault period and a recovery process are ensured.

The invention discloses a line diagnosis method and circuit, and the method and circuit are used for a data communication system, and the method comprises the steps: detecting a first current on a high-side switching tube and / or a second current on a low-side switching tube; judging the states of the high-side switch tube and the low-side switch tube based on the detection result; and judging whether open circuit and short circuit exist at the line positive end and the line negative end and whether short circuit exists between the line positive end and the line negative end and the power supply voltage and the ground voltage based on the states of the high-side switch tube and the low-side switch tube. According to the line diagnosis method and the diagnosis circuit, the accuracy of fault diagnosis in the bus power supply and power-on process can be improved, false report and missing report of faults are reduced, and chip and line burnout caused by long-time overcurrent is avoided; by means of fault detection of the communication state, the line fault diagnosis precision in bus power supply communication is improved, false alarms and missing alarms are reduced, and overcurrent is avoided.

The invention discloses a rapid pilot protection method for a flexible DC line, and the method comprises the steps: firstly collecting the positive and negative current data of the DC line in real time, calculating the current change rate, and starting protection if the current change rate exceeds a preset threshold value; locking a fault moment data window, and calculating an H distance of a positive and negative electrode current sequence based on a Hausdorff distance so as to distinguish an inter-electrode fault or a single-electrode fault; thirdly, calculating a fault current break variable sequence by using the current data in the data window to obtain a current included angle of the side; then, current included angle information of the two sides is interacted with an opposite-side protection device; calculating a product average value, namely a fault current included angle entropy, according to the current included angles on the two sides; and finally, by judging whether the included angle entropy is greater than an internal and external fault threshold value or not, accurately identifying an internal fault and triggering tripping, or judging the internal fault as an external fault. According to the method, millisecond-level rapid protection is realized through the current included angle characteristic quantity and the included angle entropy criterion, and the method has high transition resistance resistance and low communication synchronization requirements.

The invention discloses an energy storage type SOP black-start method, system and device based on improved VSG network construction control and a medium, and relates to the field of power grid black-start, and the method comprises the steps: an energy storage type converter MMC carries out the active and reactive control based on an improved VSG network construction control strategy; a non-fault side MMC is controlled to firstly close an isolation circuit breaker and slowly charge a direct-current capacitor, and when the voltage reaches a set threshold value, a current-limiting resistor is quitted; the fault side MMC is started by the same step as the non-fault side MMC; after synchronization is completed, AC circuit breakers between the non-fault side MMC and the feeder load and between the fault side MMC and the feeder load are closed respectively; based on the collected power grid power data, MMC output parameters are adjusted to meet the power grid connection condition, the control mode is switched according to the grid connection state, and the black start process is ended. And by arranging the black start resistor for current-limiting charging and sub-module voltage balance control, the phenomena of overcurrent and voltage unbalance in the black start process are avoided.

The invention discloses a network construction type VSG power grid fault active support cooperative control method, and belongs to the technical field of new energy grid-connected control. According to the method, the power grid voltage is monitored in real time, and a cooperative strategy is dynamically triggered: when the voltage drops below a set value, a cooperative control mechanism is started, including (1) self-adaptive active power adjustment based on a power angle stability margin and dynamic correction of a power instruction value to suppress kinetic energy accumulation of a rotor; (2) voltage tracking type reactive compensation is superposed in a reactive control loop, reactive current is increased in real time according to the drop depth, continuous reactive support is provided, and steady-state overcurrent is restrained; and (3) inputting a virtual resistance inductor, and limiting a transient over-current peak value by suppressing a dq-axis coupling current component. When the voltage is normal, the conventional VSG control mode is maintained. According to the invention, power-reactive power-impedance three-dimensional cooperation is realized, power angle stability, current limitation and voltage support are considered, and the stability and active support capability of the network-forming VSG under the power grid drop fault are significantly improved.

The invention relates to the technical field of overcurrent protection, in particular to an active protection control method and system for power distribution switch control equipment, and the method comprises the following steps: a current sensing device obtains a current value sequence, a sliding window generates a current slope, impedance detection obtains an impedance sequence, and an impedance rate is obtained through least square; a correction coefficient is obtained through a difference value between an impedance rate and a reference value; a disturbance rate is calculated through a current extreme value; an input classifier outputs a control instruction; a threshold and instruction logic and operation are carried out; according to the method, the coupling relation between the current slope and the impedance rate is dynamically analyzed, a multi-dimensional parameter system is constructed, a dynamic adjustment threshold value of a composite judgment basis is established, disturbance and overload are distinguished, the reliability is enhanced by combining a classifier recognition mode and logic and operation, feedback closed-loop control is introduced, the non-linear load adaptability is improved, and the maloperation rate is reduced; the sensitivity is enhanced, and the safety margin is optimized.

The invention provides a zero-voltage ride-through control method for a self-synchronizing voltage source doubly-fed wind turbine generator, which comprises the following steps that: when the self-synchronizing voltage source doubly-fed wind turbine generator is in a transient state, a grid-side converter adopts vector control, and a rotor-side converter adopts additional virtual impedance and annular current limiting; the transient overcurrent of the grid-side converter and the rotor-side converter can be effectively suppressed, so that the continuous operation capability of the wind turbine generator in the zero-voltage ride-through period can be maintained; meanwhile, by improving the transient capacity and the transient reactive current amplitude of the converter, the transient voltage supporting capacity of the wind turbine generator during the zero voltage ride-through period can be effectively provided; when the self-synchronizing voltage source doubly-fed wind turbine generator set is in a transient state, overvoltage of direct-current bus voltage is limited by a Chopper circuit, active-priority current amplitude limiting control is adopted by a grid-side converter, parameters of a current inner ring PI controller of a rotor-side converter are optimized, energy balance of a direct-current side can be achieved in the zero-voltage ride-through period, and stability of the direct-current bus voltage is maintained.

The invention provides an intelligent lightning arrester for a line. The intelligent lightning arrester comprises a lightning arrester body and an intelligent control box, the lightning arrester body is used for providing a low-impedance grounding channel for overcurrent when overvoltage caused by lightning or switching operation occurs on a line, so that the overvoltage is limited below a safety level, subsequent electrical equipment is protected from being damaged, the lightning arrester body recovers to an insulation state after the overvoltage disappears, and normal operation of a power system is guaranteed. The intelligent control box comprises an embedded intelligent sensing module and a diagnosis module, and the embedded intelligent sensing module is used for collecting operation state parameters of the lightning arrester body in real time; and the diagnosis module is used for evaluating the insulation state of the lightning arrester body by adopting a partial discharge mode recognition model according to the operation state parameters of the lightning arrester body, and predicting the aging trend of a valve plate unit of the lightning arrester body by adopting a valve plate aging trend prediction model. The lightning arrester disclosed by the invention has the dual advantages of compact structure and high-performance protection.

The invention discloses a self-adaptive current-limiting control method and related device for a network construction type energy storage converter under a symmetric fault of a power grid, and belongs to the technical field of network construction type energy storage converter control, and the method comprises the steps: constructing a corresponding fault current dynamic response model based on the network construction type energy storage converter under the symmetric fault of the power grid; generating a self-adaptive current-limiting control strategy based on the voltage drop depth of the power grid; wherein the self-adaptive current-limiting control strategy comprises the steps of carrying out overcurrent steady-state component suppression based on a phasor current-limiting method and carrying out overcurrent transient-state component suppression based on a virtual impedance control method, and self-adaptively adjusting a power instruction to meet a system support requirement in a current-limiting process; a fault current dynamic response model is solved through a self-adaptive current-limiting control strategy, a current-limiting control scheme is obtained, it can be ensured that the converter maintains the networking characteristic in the fault period, steady-state and transient overcurrent is effectively restrained, output current is strictly limited within a safety threshold value, and transient stability of a system is maintained.

The invention discloses an adaptive virtual impedance-based fault current limiting method for a network-forming converter, and belongs to the technical field of converter control. Comprising the following steps: collecting grid-side voltage, converter-side voltage and converter output current; carrying out current amplitude calculation on the grid-side voltage quantity to obtain a current effective value of the port of the converter; judging whether the current effective value of the current transformer port exceeds a current threshold value of the current transformer; and if yes, self-adaptive virtual impedance is introduced to carry out converter fault current limitation. The resistance part of the virtual impedance is used for suppressing surge current at the beginning of a fault; and the reactance part is used for suppressing the effective value of the fault transient current within the current limiting range. In the fault process, the current virtual impedance value is adaptively changed according to the effective value of the current overcurrent, and the virtual impedance can be automatically quitted after the fault end stage. The method is suitable for fault current suppression of the network-forming converter in various control modes, and has good feasibility and practical value.

The embodiment of the invention provides a flywheel energy storage system and an electrical control method and system thereof, and the electrical control method comprises the steps: collecting the operation state data of the flywheel energy storage system in real time, and carrying out the preprocessing of the operation state data; inputting the preprocessed operation state data into a parameter adaptive control algorithm, dynamically adjusting control parameters of the algorithm through fuzzy logic, and generating a control instruction for controlling the power converter; based on the control instruction and the real-time demand of a power grid, cooperatively controlling the output power and the direct-current voltage of the flywheel energy storage system, and when it is detected that the direct-current voltage deviates from a target range, automatically switching an electrical control mode to a voltage stabilization mode for stabilizing the direct-current voltage within the target range; and monitoring the operation state of the flywheel energy storage system in real time, and triggering a protection mechanism when at least one abnormity of overvoltage abnormity, overcurrent abnormity or mechanical fault abnormity is detected.

The invention relates to the technical field of fault prediction, and particularly discloses a fault prediction method and system for a high-voltage switch operating mechanism. According to the method, early-stage accurate prediction of the fault of the high-voltage switch operating mechanism is realized through multi-feature extraction and fusion in combination with a lightweight Transformer model, and compared with a traditional single current signal analysis method, the method fully considers the coupling effect of electromagnetic and mechanical states, captures electromagnetic abnormality through current-electromagnetic coordination node features, and improves the accuracy of the fault diagnosis of the high-voltage switch operating mechanism. According to the method, mechanical vibration faults are recognized through vibration energy features, motion discordance is detected through electromagnetic driving force-motion acceleration cooperative features, so that possible fault modes of the mechanism are comprehensively covered, the accuracy and the real-time performance of evaluation are further improved through efficient fusion of the lightweight Transform model, the early fault missing report rate is effectively reduced, and the reliability of the mechanism is improved. And reliable guarantee is provided for safe operation of a power system.

The invention discloses a load matching method of a tested power supply and related equipment. The method comprises the following steps: acquiring rated voltage, rated current and rated power of a tested power supply, drawing a power supply parameter curve based on the group of parameters, and determining a current turning point from the power supply parameter curve; according to the magnitude relationship between the actual output voltage of the tested power supply and the voltage corresponding to the current turning point, the rated current or rated power is flexibly selected as a reference basis to determine the resistance value of each load in the load box; and finally, selecting a plurality of loads connected in parallel from the load box as test loads according to the actual output voltage, and ensuring that the actual output current of the tested power supply reaches the rated current or the actual output power reaches the rated power. The rated current or the rated power is dynamically switched through the current turning point to serve as a reference basis, the load requirements of the tested power supply in different voltage intervals are accurately adapted, and the adaptability of load matching is greatly improved.

Technical solutions for diagnosing a sensor fault in an actuator incorporating a permanent magnet direct current (PMDC) motor are described, including: measuring, by means of a position sensor, the position of the PMDC motor; determining, based on the measured position, an estimated motor speed; measuring, by means of a current sensor, the current in the PMDC motor; determining, based on the measured current in the PMDC motor, a voltage command for the PMDC motor; determining, based on the measured current and the voltage command and using a motor speed observer, an observed speed of the PMDC motor; determining a differential speed as the difference between the estimated motor speed and the observed speed; determining, based on the differential speed, the sensor fault; and performing an action in response to the determination of the sensor fault.

The invention discloses a voltage transformer intelligent inductance adjustment verification method and device based on a current inversion capacitor, and the method comprises the steps: obtaining a preset excitation voltage and an adjustable sweep frequency, and carrying out the sweep excitation of an inductance adjustment resonant circuit according to the preset excitation voltage and the adjustable sweep frequency; acquiring current sampling data of the inductance-adjusting resonance circuit; performing frequency domain analysis on the current sampling data, and calculating an equivalent capacitance value and a resonance state parameter of the inductance-adjusting resonance circuit according to a frequency domain analysis result; and the air gap length and the winding turns of the reactor are adaptively adjusted based on the resonance state parameters. The capacitance value and the resonance state parameter of the resonance circuit are calculated through inversion of the current frequency domain analysis result, dual-mode inductance adjustment closed-loop control is achieved based on the capacitance value and the resonance state parameter, the problems that an existing manual inductance adjustment mode depends on artificial experience and is tedious in operation and low in efficiency are solved, the method can adapt to a high-capacity mutual inductor, meanwhile, a resonance point is accurately locked, and the control precision is improved. And wide-range and high-precision inductance adjustment is realized.

The invention discloses a multi-source signal fusion high-voltage switch cabinet intelligent monitoring and fault self-adaptive protection system, and relates to the technical field of switch cabinets, the system comprises a multi-source sensing module, a state evaluation module and a self-adaptive protection module, the multi-source sensing module synchronously collects UHF, AE, arc light and primary loop current, completes front-end conditioning and unifies time reference, and the state evaluation module evaluates the state of the state evaluation module and the self-adaptive protection module; and as a basis for subsequent association and calculation, the state evaluation module completes grading based on a double threshold + trend, establishes and calls a nonlinear relationship between partial discharge and overcurrent according to a baseline of the same model, and calculates residual error and durability, an output grade, a high-risk sign and an auxiliary criterion on line. The self-adaptive protection module executes arc light correlation partial discharge and arc light overcurrent fusion triggering, tripping is carried out when the fusion criterion is met, sensitivity enhancement is carried out on a correlation threshold and a front window when the residual error continuously exceeds the threshold, and the method has the advantage of being accurate in judgment.

A series-type hybrid circuit breaker to provide protection against short circuit faults in DC or AC power circuits. A series-type hybrid circuit breaker (SHCB) forces a fault current into a high-frequency AC current with zero crossings and allows a mechanical circuit breaker to disconnect the faulty branch. The SHCB injects a transient counter voltage pulse via a pulse transformer into the main power loop upon detection of an overcurrent condition and forces the fault current to change its original direction and cross zero to a negative peak value. A generation power electronic circuit on the primary side of the transformer controls the discharge of a capacitor to generate the counter voltage pulse during the first phase of each switching cycle of the fault interruption process. The power electronic circuit then changes the polarity of the injected secondary voltage and forces the fault current to change direction and cross zero again.

The invention relates to the technical field of new energy reactive compensation, and provides an electric energy quality comprehensive treatment device, which comprises an electric energy monitoring system for realizing current sampling of a 10kV bus through a current transformer, performing voltage signal acquisition through a voltage relay, and finishing protection signal monitoring in cooperation with a signal relay. Comprehensive operation parameters including system voltage, current and harmonic characteristics are formed; the controllable static compensation system is used for establishing a stepped reactive compensation network with a harmonic suppression function by combining a series resonance suppression loop formed by an inductor and a capacitive compensation branch formed by a driving capacitor based on the comprehensive operation parameters through intelligent switching control of a contactor; and the dynamic reactive power regulation system is used for the stepped reactive power compensation network to realize voltage matching through a transformer according to real-time compensation requirements, and then the stepped reactive power compensation network is connected to a static var generator to generate compensation current opposite to the phase of the reactive component of the system. Fine adjustment can be achieved, the compensation precision is high, and the compensation effect is good.

Certain aspects of the present disclosure generally relate to electronic circuits and, more particularly, to techniques and apparatus for signal amplification. One example apparatus generally includes: a current sensor configured to sense a current associated with an amplifier; and a voltage sensor configured to sense a voltage associated with the amplifier. The apparatus may also include a logic circuit configured to: detect a first over-current condition associated with the amplifier based on the current; detect a first over-voltage condition associated with the amplifier based on the voltage; and adjust an amplification gain to yield a first adjusted gain level for an input signal based on detection of the first over-current condition and the first over-voltage condition, wherein the amplifier is configured to amplify the input signal based on the first adjusted gain level.

The invention relates to the technical field of power electronic application, in particular to a negative-sequence voltage compensation control method of a network-forming STATCOM (Static Synchronous Compensator). Comprising the steps of bridge arm current reference instruction unit phasor calculation, reactive voltage control, bridge arm positive sequence and negative sequence reactive current instruction calculation, bridge arm current reference instruction amplitude limiting logic, zero sequence voltage injection control and modulation wave instruction calculation. According to the method, the negative-sequence current output by the networking STATCOM in the asymmetric transient fault is always inductive, the proportion coefficient of the amplitude of the negative-sequence current instruction can be adjusted according to the requirements of an engineering project, and the cost is reduced; by dynamically solving a quadratic equation of unary of a reactive current amplitude limiting coefficient, an active current instruction is not limited by amplitude, balance control of direct current voltage is preferentially ensured, the reactive current is reasonably limited in amplitude, a total current reference instruction value is always in a maximum design value range of short-time overcurrent, and the stability and the safety of the device are improved.

The invention relates to a method for detecting failure of a power module. The method comprises the following steps: monitoring voltage data of bus voltage in a pre-charging stage of a high-voltage system; when the voltage data exceeds a preset safe voltage threshold value, the driving circuit is controlled to alternately output PWM driving signals with set frequency and set duty ratio to a lower bridge arm and an upper bridge arm of the power module, so that the upper bridge arm and the lower bridge arm are alternately conducted; in the alternating conduction process of the upper bridge arm and the lower bridge arm, monitoring whether a preset fault signal is detected within a set time; and judging whether the power module fails based on the detection result. The power module failure detection method can effectively identify whether the power module has the fault condition of short circuit of the upper bridge arm chip or the lower bridge arm chip CE, thereby preventing serious safety accidents such as bridge arm direct connection and secondary overcurrent caused by driving the failed power module from the source, ensuring the safe operation of a high-voltage system, and improving the reliability of the power module. And the starting safety and the operation reliability of the electric drive system are greatly improved.

The invention relates to the technical field of power electronic application, in particular to a control method of a star-chain network STATCOM (static synchronous compensator). Comprising positive sequence voltage unit phasor calculation, voltage feed-forward unit phasor calculation, bridge arm current reference instruction unit phasor calculation, reactive voltage control, bridge arm reactive non-limiting current reference instruction calculation, bridge arm reactive current reference instruction amplitude limiting logic, zero sequence voltage injection control and modulation wave instruction calculation. The bridge arm current reference instruction comprises a negative sequence component, and negative sequence compensation of the power grid voltage is realized; bridge arm current reference instruction amplitude limiting logic is designed, so that the safety of the device is effectively guaranteed; in the zero-sequence voltage injection control link, the phase with the functional quantity deviation adopts a current reference instruction phasor signal, and the dynamic adjustment efficiency is optimized; the equalization control effect of the inter-phase direct current voltage is enhanced, and the problem that overcurrent is easy to occur in transient faults of a network-forming STATCOM and the problem that a current instruction contains a direct current component are solved.

A method is for adaptively controlling a charging module that converts three-phase AC input to DC output with improved power factor correction. The method includes performing Clarke and Park transforms on input three-phase AC voltages to obtain d-q axis components, measuring and transforming boost inductor currents to obtain current axis components, generating control values through current-loop and voltage-loop modules based on target and measured values, and synthesizing PWM signals to control switching operations. The method features adaptive phase angle computation using a proportional-integral controller that responds to load variations in real-time. The control system maintains high power factor under varying load conditions by continuously adjusting the phase reference based on the q-axis voltage error. This approach minimizes power losses, reduces harmonic distortion, and ensures stable operation across the full operating range of the charging module while maintaining unity power factor.

The invention discloses a double-pulse test protection circuit, relates to the field of power electronics, and is characterized in that a third switch, a current detection device and a control module are additionally arranged on the basis of an original double-pulse test circuit, and the purpose of the scheme is to collect the current value of a loop where an inductor is located through the current detection device; when the current value of the loop where the inductor is located is larger than a preset current threshold value (the current value of the loop is too high), the first switch is automatically switched off through the control module, and then the whole double-pulse test protection circuit is switched off. The current value in the double-pulse test protection circuit is not increased any more, and the reliability and safety of the scheme are ensured.

A circuit arrangement for current limiting and an electrical system comprising such a circuit arrangement. An output terminal of a current limiting control circuit is connected to a control input of a semiconductor switch via a limiting resistor (RB). The current limiting control circuit is configured to change an output impedance of the current limiting control circuit at the output terminal. The semiconductor switch is configured to set a current (I) in a circuit between an electrical power source and a load. An inductor (L) is configured to be connected to the electrical power source and to a terminal of the load and an input of the current limiting control circuit is connected to the inductor (L). The current limiting control circuit is configured to detect an overcurrent-related voltage drop (VL) of the inductor (L) and reduce its output impedance to increase an output impedance of the semiconductor switch.

The invention discloses a turn-off delay time detection device and a turn-off delay time detection method for on-line junction temperature detection, and aims to solve the contradiction between high voltage tolerance and accurate detection of a low voltage part in a traditional detection method and realize reliable on-line detection of the junction temperature of a power switch device. Comprises: a displacement current extraction circuit detects a capacitor element current having a function relationship with voltages at two ends of a detected power switch device, and outputs an electric signal containing current information; the starting moment detection circuit receives a grid voltage signal and detects a starting moment according to the standard that the grid voltage drops to 90% of a high level, and the ending moment detection circuit receives a current information electric signal and detects an ending moment according to an experimental calibration threshold; the turn-off delay time extraction circuit generates a signal containing delay time based on the time information; the controller calculates the junction temperature according to the calibration relation between the delay time and the junction temperature. High-voltage impact is avoided through indirect current detection, all links are accurately matched, and the device is suitable for various circuit scenes and has low cost and high reliability.

A controller for a multiphase voltage regulator in a multi-rail power supply system has a dynamic overcurrent unit and a switch control circuit. The dynamic overcurrent unit provides an overcurrent threshold based on a system-input current which indicates a total input current of the multiphase voltage regulator and at least another voltage regulator. The switch control circuit provides a plurality of switch control signals to control a plurality of switching circuits of the multiphase voltage regulator, such that an output voltage of the multiphase voltage regulator is regulated to a predetermined voltage level and an output current of the plurality of switching circuits is controlled based on the overcurrent threshold.

A shutdown device includes: a pyro-fuse that includes a bus bar inserted into a power supply path and a piston disposed above the bus bar, the piston moving toward the bus bar to divide the bus bar; and a melting fuse connected in parallel to the pyro-fuse, in which the melting fuse includes a fuse case, a fuse element provided in the fuse case and is fused when an overcurrent flows, and an arc-extinguishing material provided in the fuse case and being in a granular phase, and the fuse element extends along a direction intersecting a direction in which the piston moves.

The present application provides a kind of driving device, prevent the overcurrent detection input terminal voltage due to the current flowing in the chip peripheral ground wiring rises and thus generates the false operation of overcurrent detection circuit.In the IS terminal of overcurrent detection circuit arranged in the position far away from GND terminal and the B point of chip peripheral ground wiring (11) are provided as terminal protection circuit transistor MN1, in the CFO terminal arranged in the position further away from GND terminal and the C point of chip peripheral ground wiring (11) are provided as terminal protection circuit zener diode ZD1.In addition, the input of the acceptance threshold voltage of comparator COMP_IS and the B point of chip peripheral ground wiring (11) are provided as potential offset element transistor MN2.Between thus, when the potential of B point rises due to the overvoltage applied to CFO terminal, by making the two input terminals of comparator COMP_IS also rise, thereby preventing false operation.