Detection circuit for abnormal conduction of switching tube

Abstract

The embodiment of the invention provides a detection circuit for abnormal conduction of a switching tube, which comprises a bridge type switching circuit, a direct current bus circuit and an alternating current bus circuit which are connected with the bridge type switching circuit, and a voltage sampling circuit and a current sampling circuit which are respectively connected with the direct current bus circuit and the alternating current bus circuit, the detection module is respectively connected with the voltage sampling circuit and the current sampling circuit, the main control module is connected with the detection module, the direct-current bus circuit and the alternating-current bus circuit are sampled through the voltage sampling circuit and the current sampling circuit, then sampling signals are detected through the detection module, and a detection result is sent to the main control module. The main control module controls the bridge type switching circuit to stop receiving the direct current voltage of the direct current bus circuit when the switching tube is abnormally conducted according to the judgment result, so that driving waveform abnormal conduction detection is performed on the switching tube, and a protection mechanism is triggered under the abnormal conduction condition; and the operation stability and reliability of the switching power supply are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a detection circuit for abnormal conduction of a switch tube. Background Art

[0002] MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is a semiconductor device widely used in electronic circuits, especially in the fields of digital circuits and power management. It has become a core component in modern integrated circuit design due to its high performance, low power consumption and high-speed switching.

[0003] When using a power MOSFET bridge topology, the gate drive signal of the two power devices on the same bridge arm may oscillate during the conversion process, resulting in a significant increase in the power device loss. When the oscillation amplitude is high, it may even cause the power device to turn on unexpectedly, thereby causing the power switch tube to be forward-biased, ultimately causing device damage. However, conventional MOSFET protection strategies cannot diagnose the problem of transient forward-biased failure of the upper and lower MOSFETs. Summary of the invention

[0004] In view of the above problems, an embodiment of the present invention is proposed to provide a detection circuit for abnormal conduction of a switch tube that overcomes the above problems or at least partially solves the above problems.

[0005] In order to solve the above problem, an embodiment of the present invention discloses a detection circuit for abnormal conduction of a switch tube, comprising:

[0006] A bridge switch circuit, a DC bus circuit and an AC bus circuit connected to the bridge switch circuit, a voltage sampling circuit and a current sampling circuit respectively connected to the DC bus circuit and the AC bus circuit, a detection module respectively connected to the voltage sampling circuit and the current sampling circuit, and a main control module connected to the detection module;

[0007] The bridge switch circuit is used to convert the DC voltage of the DC bus circuit into an AC voltage and transmit the AC voltage to the AC bus circuit;

[0008] The voltage sampling circuit is used to sample the voltages of the DC bus circuit and the AC bus circuit, and transmit the voltage sampling signals to the detection module;

[0009] The current sampling circuit is used to sample the current of the DC bus circuit and the AC bus circuit, and transmit the current sampling signal to the detection module;

[0010] The detection module is used to determine whether the switch tube of the bridge switch circuit is abnormally turned on according to the voltage sampling signal and the current sampling signal, and send the determination result to the main control module;

[0011] The main control module is used to determine whether the switch tube of the bridge switch circuit is abnormally turned on according to the judgment result, and when the switch tube of the bridge switch circuit is abnormally turned on, control the bridge switch circuit to stop receiving the DC voltage of the DC bus circuit.

[0012] Optionally, the DC bus circuit includes multiple capacitors and a DC bus; the DC bus includes a positive pole and a negative pole; the multiple capacitors are connected in parallel between the positive pole and the negative pole of the DC bus, for transmitting the DC voltage of the DC bus to the bridge switching circuit.

[0013] Optionally, the DC bus circuit also includes a contactor; one end of the contactor is connected to the positive pole of the DC bus, and the other end is connected to the bridge switch circuit, for controlling whether the DC voltage of the positive pole of the DC bus is transmitted to the bridge switch circuit.

[0014] Optionally, the bridge switch circuit includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; the first switch tube and the third switch tube are upper bridge switch tubes, the second switch tube and the fourth switch tube are lower bridge switch tubes, the first switch tube and the third switch tube are used to receive the DC voltage of the positive pole of the DC bus; the second switch tube and the fourth switch tube are used to receive the DC voltage of the negative pole of the DC bus.

[0015] Optionally, the input end of the first switch tube is connected to the positive pole of the DC bus, and the output end is connected to the second switch tube; the input end of the second switch tube is connected to the negative pole of the DC bus, and the output end is connected to the fourth switch tube; the input end of the third switch tube is connected between the positive pole of the DC bus and the first switch tube, and the output end is connected to the fourth switch tube; the input end of the fourth switch tube is connected between the negative pole of the DC bus and the second switch tube, and the output end is connected to the third switch tube.

[0016] Optionally, the bridge switching circuit includes a first output end and a second output end; the first output end is arranged between the first switch tube and the second switch tube, and is used to output the AC voltage; the second output end is arranged between the third switch tube and the fourth switch tube, and is used to output the AC voltage.

[0017] Optionally, the AC bus circuit includes an AC bus, a first inductor and a second inductor; the AC bus includes a live wire and a neutral wire; one end of the first inductor is connected to the first output terminal, and the other end is connected to the live wire of the AC bus; one end of the second inductor is connected to the second output terminal, and the other end is connected to the neutral wire of the AC bus.

[0018] Optionally, the voltage sampling circuit includes: at least one voltage sampling resistor, a first bypass capacitor and a first filter capacitor connected to the voltage sampling resistor, and a first operational amplifier having one end connected to the voltage sampling resistor and the other end outputting the voltage sampling signal.

[0019] Optionally, the current sampling circuit includes: at least one current sampling resistor, a second bypass capacitor and a second filter capacitor connected to the current sampling resistor, and a second operational amplifier having one end connected to the current sampling resistor and the other end outputting the current sampling signal.

[0020] Optionally, the detection module includes a short-circuit detection module and an oscillation detection module; the short-circuit detection module is used to receive the current sampling signal, and determine whether the bridge switch circuit is short-circuited based on the current sampling signal, and send the determination result to the main control module; the oscillation detection module is used to receive the current sampling signal and the voltage sampling signal, and determine whether the switch tube of the bridge switch circuit is abnormally turned on based on the current sampling signal and the voltage sampling signal, and send the determination result to the main control module.

[0021] Optionally, the main control module is used to stop sending pulse signals to the bridge switch circuit when the switch tube of the bridge switch circuit is abnormally turned on.

[0022] The embodiments of the present invention include the following advantages:

[0023] The detection circuit for abnormal conduction of a switch tube in an embodiment of the present invention includes a bridge switch circuit, a DC bus circuit and an AC bus circuit connected to the bridge switch circuit, a voltage sampling circuit and a current sampling circuit respectively connected to the DC bus circuit and the AC bus circuit, a detection module respectively connected to the voltage sampling circuit and the current sampling circuit, and a main control module connected to the detection module, wherein the bridge switch circuit is used to convert the DC voltage of the DC bus circuit into an AC voltage and transmit the AC voltage to the AC bus circuit; the voltage sampling circuit is used to sample the voltage of the DC bus circuit and the AC bus circuit and transmit the voltage sampling signal to the detection module; the current sampling circuit is used to sample the current of the DC bus circuit and the AC bus circuit and transmit the current sampling signal to the detection module; the detection module is used to judge whether the switch tube of the bridge switch circuit is abnormally conducted according to the voltage sampling signal and the current sampling signal, and send the judgment result to the main control module; the main control module is used to determine whether the switch tube of the bridge switch circuit is abnormally conducted according to the judgment result, and when the switch tube of the bridge switch circuit is abnormally conducted, control the bridge switch circuit to stop receiving the DC voltage of the DC bus circuit. The voltage sampling circuit and the current sampling circuit are used to sample the voltage and current of the DC bus circuit and the AC bus circuit connected to the bridge switch circuit. Then, the voltage sampling signal and the current sampling signal are detected by the detection module and the detection result is sent to the main control module. The main control module determines whether the switch tube of the bridge switch circuit is abnormally turned on according to the judgment result, and when the switch tube of the bridge switch circuit is abnormally turned on, the bridge switch circuit is controlled to stop receiving the DC voltage of the DC bus circuit, thereby realizing the abnormal conduction detection of the driving waveform of the switch tube. If abnormal conduction occurs, the protection mechanism is triggered, thereby improving the operating stability and reliability of the switching power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a detection circuit for abnormal conduction of a switch tube according to an embodiment of the present invention;

[0025] Figure 2 is a structural schematic diagram of another abnormal conduction detection circuit of a switch tube according to an embodiment of the present invention;

[0026] Figure 3 is a schematic structural diagram of a voltage sampling circuit according to an embodiment of the present invention;

[0027] Figure 4 It is a structural schematic diagram of a current sampling circuit according to an embodiment of the present invention.

[0028] Bridge switch circuit 10, first switch tube 11, second switch tube 12, third switch tube 13, fourth switch tube 14, first output end 15, second output end 16, DC bus circuit 20, capacitor 21, DC bus 22, contactor 23, AC bus circuit 30, AC bus 31, first inductor 32, second inductor 33, voltage sampling circuit 40, voltage sampling resistor 41, voltage sampling point 411, first bypass capacitor 42, first filter capacitor 43, first operational amplifier 44, current sampling circuit 50, current sampling resistor 51, current sampling point 511, second bypass capacitor 52, second filter capacitor 53, second operational amplifier 54, detection module 60, main control module 70. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] When using a power MOSFET bridge topology, the gate drive signal of the two power devices on the same bridge arm may oscillate during the conversion process, resulting in a significant increase in the power device loss. When the oscillation amplitude is high, it may even cause the power device to turn on unexpectedly, thereby causing the power switch tube to be forward-biased, ultimately causing device damage. However, conventional MOSFET protection strategies cannot diagnose the problem of transient forward-biased failure of the upper and lower MOSFETs.

[0031] One of the core concepts of the embodiment of the present invention is to perform voltage sampling and current sampling on the DC bus circuit and the AC bus circuit connected to the bridge switching circuit through a voltage sampling circuit and a current sampling circuit, and then detect the voltage sampling signal and the current sampling signal through a detection module and send the detection result to the main control module. The main control module determines whether the switch tube of the bridge switching circuit is abnormally turned on according to the judgment result, and when the switch tube of the bridge switching circuit is abnormally turned on, controls the bridge switching circuit to stop receiving the DC voltage of the DC bus circuit, thereby realizing abnormal conduction detection of the driving waveform of the switch tube. If abnormal conduction occurs, the protection mechanism is triggered, thereby improving the operating stability and reliability of the switching power supply.

[0032] Reference Figure 1 , shows a schematic diagram of the structure of a detection circuit for abnormal conduction of a switch tube according to an embodiment of the present invention, which may specifically include the following structure:

[0033] A bridge switching circuit 10, a DC bus circuit 20 and an AC bus circuit 30 connected to the bridge switching circuit 10, a voltage sampling circuit 40 and a current sampling circuit 50 respectively connected to the DC bus circuit 20 and the AC bus circuit 30, a detection module 60 respectively connected to the voltage sampling circuit 40 and the current sampling circuit 50, and a main control module 70 connected to the detection module 60.

[0034] The bridge switch circuit 10 is used to convert the DC voltage of the DC bus circuit 20 into an AC voltage, and transmit the AC voltage to the AC bus circuit 30 .

[0035] The main feature of the bridge switching circuit is that it can effectively control the direction and size of the current, thereby realizing the conversion and regulation of voltage. The bridge switching circuit is usually composed of four switching devices (such as MOSFET, IGBT, etc.), which are switched in a specific order to control the flow path of the current. The bridge circuit can be divided into two main types: the full-bridge circuit, which consists of four switching devices and can realize the conversion of positive and negative voltages; the half-bridge circuit, which consists of two switching devices and is usually used for lower power applications.

[0036] A DC bus circuit 20 and an AC bus circuit 30 are connected to the bridge switching circuit 10 .

[0037] The circuit of the embodiment of the present invention can be a bidirectional inverter power supply circuit. The bidirectional inverter power supply can realize the bidirectional flow of electric energy, that is, it can convert direct current into alternating current (inversion) and can also convert alternating current into direct current (rectification). The bidirectional inverter power supply is usually composed of the following main parts: switching devices, such as MOSFET, IGBT, etc., used to control the flow direction and size of electric energy; filters, used to smooth the output voltage and current, reduce harmonics and noise; control circuits, used to adjust the on and off time of the switching devices, to achieve precise control of voltage and current; the DC side and the AC side, respectively connected to the DC power supply (such as batteries, super capacitors, etc.) and the AC load (such as power grids, motors, etc.). The working principle of the bidirectional inverter power supply is based on the switching power supply technology, and the bidirectional flow of electric energy is achieved by controlling the on and off time of the switching devices. The following are the basic working modes of bidirectional inverter power supplies: Inversion mode (DC to AC), converting direct current into alternating current. Working principle: the control circuit controls the on and off of the switching device according to a specific frequency and phase, and converts the DC voltage into AC voltage by periodically switching and shutting down. The frequency and phase of the output AC voltage can be adjusted by the control circuit; Rectification mode (AC to DC): converting alternating current into direct current. Working principle: the control circuit detects the phase and frequency of the input AC voltage, and controls the on and off of the switching device according to the detection results, converting the AC voltage into DC voltage, and smoothing the output DC voltage through a filter to reduce ripple and noise.

[0038] The DC bus circuit 20 is the DC side of the bidirectional inverter power supply, and the AC bus circuit 30 is the AC side of the bidirectional inverter power supply.

[0039] The voltage sampling circuit 40 is used to sample the voltage of the DC bus circuit 20 and the AC bus circuit 30, and transmit the voltage sampling signal to the detection module 60. The current sampling circuit 50 is used to sample the current of the DC bus circuit 20 and the AC bus circuit 30, and transmit the current sampling signal to the detection module 60.

[0040] The detection module 60 is used to determine whether the switch tube of the bridge switch circuit 10 is abnormally turned on according to the voltage sampling signal and the current sampling signal, and send the determination result to the main control module 70.

[0041] The main control module 70 is used to determine whether the switch tube of the bridge switch circuit 10 is abnormally turned on according to the judgment result, and when the switch tube of the bridge switch circuit 10 is abnormally turned on, control the bridge switch circuit 10 to stop receiving the DC voltage of the DC bus circuit 20.

[0042] The detection circuit of abnormal conduction of the switch tube in the embodiment of the present invention includes a bridge switch circuit 10, a DC bus circuit 20 and an AC bus circuit 30 connected to the bridge switch circuit 10, a voltage sampling circuit 40 and a current sampling circuit 50 respectively connected to the DC bus circuit 20 and the AC bus circuit 30, a detection module 60 respectively connected to the voltage sampling circuit 40 and the current sampling circuit 50, and a main control module 70 connected to the detection module 60, wherein the bridge switch circuit 10 is used to convert the DC voltage of the DC bus circuit 20 into an AC voltage and transmit the AC voltage to the AC bus circuit 30; the voltage sampling circuit 40 is used to detect the DC bus circuit 20 and the AC bus circuit The main control module 70 is used to determine whether the switch tube of the bridge switch circuit 10 is abnormally turned on according to the judgment result, and when the switch tube of the bridge switch circuit 10 is abnormally turned on, control the bridge switch circuit 10 to stop receiving the DC voltage of the DC bus circuit. The voltage sampling circuit 40 and the current sampling circuit 50 are used to sample the voltage and current of the DC bus circuit 20 and the AC bus circuit 30 connected to the bridge switch circuit 10, and then the voltage sampling signal and the current sampling signal are detected by the detection module 60 and the detection result is sent to the main control module 70. The main control module 70 determines whether the switch tube of the bridge switch circuit 10 is abnormally turned on according to the judgment result, and when the switch tube of the bridge switch circuit 10 is abnormally turned on, the bridge switch circuit 10 is controlled to stop receiving the DC voltage of the DC bus circuit, thereby realizing the abnormal conduction detection of the driving waveform of the switch tube. If abnormal conduction occurs, the protection mechanism is triggered, thereby improving the operating stability and reliability of the switching power supply.

[0043] Reference Figure 2 , shows a structural schematic diagram of another switch tube abnormal conduction detection circuit according to an embodiment of the present invention.

[0044] The DC bus circuit 20 includes multiple capacitors 21 and a DC bus 22; the DC bus 22 includes a positive electrode and a negative electrode; multiple capacitors 21 are connected in parallel between the positive electrode and the negative electrode of the DC bus 22, and are used to transmit the DC voltage of the DC bus 22 to the bridge switching circuit 10.

[0045] The DC bus usually refers to the common connection point or bus used to transmit DC power in the system. It connects power supplies, loads, converters and other power electronic devices to ensure efficient transmission and distribution of power. The positive and negative poles of the DC bus are two key connection points in the DC power system. They represent the high potential and low potential of the DC voltage respectively. "DCBUS+" represents the high potential end (positive pole) of the DC bus, and "DCBUS-" represents the low potential end (negative pole) of the DC bus. The current flows from "DCBUS+" to "DCBUS-". The positive pole of the DC power supply is connected to the positive end of the DC bus, the negative pole of the DC power supply is connected to the negative end of the DC bus, the positive pole of the load is connected to the positive end of the DC bus, and the negative pole of the load is connected to the negative end of the DC bus.

[0046] Capacitors can be polarized capacitors, also known as polarized capacitors or polarized capacitors. They are capacitors whose internal structure determines that they have clear positive and negative polarities. Polarized capacitors must be connected correctly in the circuit, otherwise it may cause damage to the capacitor or even explode. Polarized capacitors usually consist of the following main parts: the positive electrode, the high potential end of the capacitor; the negative electrode, the low potential end of the capacitor; the electrolyte, the medium used to store charge; the insulating layer, the medium used to isolate the positive and negative electrodes. The working principle of polarized capacitors is based on the process of charge storage and release. When the capacitor is connected to a power supply, the charge accumulates between the positive and negative electrodes to form an electric field. Polarized capacitors have higher capacitance and can provide a larger charge storage capacity in a smaller volume. They are suitable for occasions that require large-capacity capacitors, such as power filtering, energy storage, etc.

[0047] Multiple capacitors 21 are connected in parallel between the positive and negative electrodes of the DC bus 22. The positive electrodes of multiple capacitors 21 are connected together to form a common positive electrode, and the negative electrodes of multiple capacitors 21 are connected together to form a common negative electrode. The common positive electrode is connected to the positive electrode of the DC bus 22, and the common negative electrode is connected to the negative electrode of the DC bus 22. The load is connected between the common positive electrode and the common negative electrode. Multiple capacitors 21 are connected in parallel to transmit the DC voltage of the DC bus 22 to the bridge switch circuit 10. Connecting multiple capacitors in parallel can effectively filter out ripples and noise in the power supply, improve the stability and reliability of the power supply, provide greater charge storage capacity, meet high energy requirements, reduce equivalent series resistance (ESR), improve reliability, disperse current loads, and improve circuit performance.

[0048] In the embodiment of the present invention, the DC bus circuit 20 further includes a contactor 23; one end of the contactor 23 is connected to the positive electrode of the DC bus 22, and the other end is connected to the bridge switch circuit 10, and is used to control whether the DC voltage of the positive electrode of the DC bus 22 is transmitted to the bridge switch circuit 10. Specifically, one end of the contactor 23 is connected to the output end of the common positive electrode of the plurality of capacitors 21 connected in parallel.

[0049] Contactors are used to control the switching operation of high current loads in power systems. Contactors are often used for motor start, stop and reversal control, as well as remote control and protection in industrial automation systems. The main features of contactors are that they can withstand high current and high voltage, and have high mechanical and electrical life. The working principle of contactors is based on electromagnetic induction and mechanical movement. Power-on state: when the electromagnetic coil is energized, a magnetic field is generated to attract the armature, and the armature drives the contacts to close and connect the circuit; power-off state: when the electromagnetic coil is de-energized, the magnetic field disappears, the armature returns to its original position under the action of the spring, the contacts are disconnected, and the circuit is disconnected. Contactors can withstand high current and high voltage, and are suitable for high-power loads. Contactors have high mechanical and electrical life and can withstand frequent switching operations. Contactors can achieve remote control and automatic operation through electromagnetic coils to improve production efficiency. Contactors are usually used in conjunction with thermal relays to achieve overload protection and protect equipment and system safety.

[0050] In an embodiment of the present invention, the bridge switch circuit 10 includes a first switch tube 11, a second switch tube 12, a third switch tube 13 and a fourth switch tube 14; the first switch tube 11 and the third switch tube 13 are upper bridge switch tubes, the second switch tube 12 and the fourth switch tube 14 are lower bridge switch tubes, the first switch tube 11 and the third switch tube 13 are used to receive the DC voltage of the positive pole of the DC bus 22; the second switch tube 12 and the fourth switch tube 14 are used to receive the DC voltage of the negative pole of the DC bus 22.

[0051] The bridge switch circuit 10 may be a full-bridge switch circuit. It should be noted that the switch tube device may be a switch device such as a MOSFET, an IGBT, or a gallium nitride switch tube.

[0052] The full-bridge switching circuit is usually connected to the two ends of a DC power supply. The output end of the circuit is connected to the load, and the switching device is used to control the direction and size of the current flow. The DC power supply provides a DC voltage and is usually connected to the two ends of the full-bridge circuit. The load consumes electrical energy and is usually connected to the output end of the full-bridge circuit. The control circuit is used to adjust the on and off time of the switching device to achieve precise control of voltage and current. The working principle of the full-bridge switching circuit is based on the periodic on and off of the switching device. By controlling the on and off time of the switching device, the conversion and regulation of voltage and current are achieved.

[0053] In the embodiment of the present invention, the input end of the first switch tube 11 is connected to the positive electrode of the DC bus 22, and the output end is connected to the second switch tube 12; the input end of the second switch tube 12 is connected to the negative electrode of the DC bus 22, and the output end is connected to the fourth switch tube 14; the input end of the third switch tube 13 is connected between the positive electrode of the DC bus 22 and the first switch tube 11, and the output end is connected to the fourth switch tube 14; the input end of the fourth switch tube 14 is connected between the negative electrode of the DC bus 22 and the second switch tube 12, and the output end is connected to the third switch tube 13.

[0054] The first switch tube 11 and the third switch tube 13 are upper bridge switch tubes, the second switch tube 12 and the fourth switch tube 14 are lower bridge switch tubes, the first switch tube 11 and the fourth switch tube 14 are a pair of bridge arms; the second switch tube 12 and the third switch tube 13 are a pair of bridge arms. The bidirectional inverter power supply bridge circuit usually adopts an H-bridge circuit structure, including four switch tubes (such as IGBT or MOSFET) to form an H shape, with a DC power supply or energy storage component (such as a battery) in the middle, and the two ends are connected to the AC load (or power grid). There are two working modes: Inverter mode (DC to AC): When the circuit needs to convert DC power into AC power, the four switch tubes will be switched in a complementary manner to form an AC voltage. Specifically, two diagonal switch tubes (such as the first switch tube 11 and the fourth switch tube 14) are turned on at the same time, and then the other two diagonal switch tubes (the second switch tube 12 and the third switch tube 13) are turned on to form a sine wave or square wave AC output; Rectification mode (AC to DC): When the circuit needs to convert AC into DC, the actual process is to achieve energy rectification and accumulation through diode rectification or active switching of the switch tubes in the circuit. For example, in the positive half cycle of AC, the first switch tube 11 and the second switch tube 12 are controlled to be turned on to form a forward voltage; on the contrary, in the negative half cycle of AC, the third switch tube 13 and the fourth switch tube 14 are controlled to be turned on to form a reverse voltage, thereby outputting DC.

[0055] In an embodiment of the present invention, the bridge switch circuit 10 includes a first output terminal 15 and a second output terminal 16; the first output terminal 15 is arranged between the first switch tube 11 and the second switch tube 12, and is used to output the AC voltage; the second output terminal 16 is arranged between the third switch tube 13 and the fourth switch tube 14, and is used to output the AC voltage.

[0056] In an embodiment of the present invention, the AC bus circuit 30 includes an AC bus 31, a first inductor 32 and a second inductor 33; the AC bus 31 includes a live wire and a neutral wire; one end of the first inductor 32 is connected to the first output terminal 15, and the other end is connected to the live wire of the AC bus 31; one end of the second inductor 33 is connected to the second output terminal 16, and the other end is connected to the neutral wire of the AC bus 31.

[0057] AC bus usually refers to the common connection point or bus used to transmit AC power in the system. It connects power sources, loads, transformers, circuit breakers and other power equipment to ensure efficient transmission and distribution of power. The working principle of AC bus is based on the following key points: power transmission, AC bus as a common path for power transmission, connecting power sources and loads, through the AC bus, power is transmitted from the power source to the load to ensure the normal operation of the load; voltage regulation, the voltage on the AC bus needs to remain stable to ensure the normal operation of the load, through the transformer and voltage regulator, the voltage on the AC bus can be adjusted to adapt to different load requirements. In order to ensure the safety and reliability of the AC bus, the following protection measures are usually required: overvoltage protection, use overvoltage protection devices (such as lightning arresters, varistors, etc.) to prevent excessive voltage from damaging the equipment; overcurrent protection, use overcurrent protection devices (such as fuses, circuit breakers, etc.) to prevent excessive current from damaging the equipment; short-circuit protection, use short-circuit protection devices (such as fuses, circuit breakers, etc.) to prevent short-circuit faults from damaging the equipment; insulation protection, use insulating materials and tools to ensure safe operation and prevent electric shock accidents.

[0058] The AC busbar usually includes the live wire and the neutral wire, which are two key components in the AC power system. The live wire and the neutral wire represent the high potential and low potential of the AC voltage respectively. The live wire is the high potential end of the AC voltage, usually represented by "L", which provides the high potential of electric energy, and the current flows from the live wire to the neutral wire; the neutral wire is the low potential end of the AC voltage, usually represented by "N", which provides the low potential of electric energy, and the current flows from the live wire to the neutral wire.

[0059] Inductance is a basic component in circuits that is used to store and release magnetic field energy. An inductor is an electronic component, usually composed of a coil. When current passes through the coil, a magnetic field is generated around it. Inductors play many important roles in circuits, including filtering, energy storage, signal coupling, and impedance matching. The working principle of inductance is based on Faraday's Law of Electromagnetic Induction and Lenz's Law. When current passes through an inductor, a magnetic field is generated around it. The change in the magnetic field induces an electromotive force (voltage) in the inductor, thereby hindering the change of current. Inductors are widely used in various electronic devices and systems, including: power filtering, used to filter out ripple and noise in the power supply, and improve the stability and reliability of the power supply; energy storage, used to store electrical energy, such as battery charging and discharging, to improve energy utilization efficiency and extend equipment life; signal coupling, used for signal coupling and decoupling, to improve signal transmission quality and system stability; impedance matching, used to match the impedance between different circuits, reduce signal reflection and loss, and improve signal transmission efficiency and system performance.

[0060] Reference Figure 3 , shows a schematic diagram of the structure of a voltage sampling circuit according to an embodiment of the present invention, the voltage sampling circuit 40 includes: at least one voltage sampling resistor 41, a first bypass capacitor 42 and a first filter capacitor 43 connected to the voltage sampling resistor 41, and a first operational amplifier 44 having one end connected to the voltage sampling resistor 41 and the other end outputting the voltage sampling signal.

[0061] The voltage sampling circuit 40 is used to sample the voltage of the DC bus circuit 20 and the AC bus circuit 30. The voltage sampling point 411 is as follows: Figure 2 As shown, of course, the specific selection of the voltage sampling point 411 can be adjusted according to actual needs. The first operational amplifier 44 outputs the voltage sampling signal to the main control chip 70, and the detection module 60 can include the main control chip 70.

[0062] A sampling resistor is a resistor used to measure current or voltage. It is commonly used in applications such as current detection, voltage detection, and signal conditioning. The sampling resistor measures current indirectly by measuring the voltage drop across it, or by adjusting the input voltage to fit the input voltage range of the ADC (Analog-to-Digital Converter) through the voltage divider principle. By using the voltage divider principle, the voltage range of the input ADC is adjusted to fit the input range of the ADC. The appropriate resistance value is selected to ensure that the voltage signal at the sampling point accurately reflects the actual voltage value, while taking into account the input impedance to prevent the original circuit from being affected. Sometimes a current limiting resistor is used at the ADC input to prevent excessive input current from damaging the ADC.

[0063] A bypass capacitor is a capacitor used to bypass high-frequency noise. It is usually connected between the power supply and the ground to filter out high-frequency noise in the power supply to ensure the stability of the power supply and the purity of the signal. The working principle of the bypass capacitor is based on the impedance characteristics of the capacitor. For high-frequency signals, the impedance of the capacitor is low and can be regarded as a short circuit, thereby bypassing the high-frequency noise to the ground. For low-frequency signals, the impedance of the capacitor is high and can be regarded as an open circuit, which does not affect the transmission of low-frequency signals.

[0064] A filter capacitor is a capacitor used to filter out ripple and noise in a power supply. It is usually connected between the power supply output terminal and the ground to smooth the power supply output voltage and ensure the normal operation of the load. The working principle of the filter capacitor is based on the charging and discharging process of the capacitor. When the power supply output voltage fluctuates, the filter capacitor will charge and discharge to smooth the output voltage and reduce ripple and noise.

[0065] Reference Figure 4 , shows a schematic diagram of the structure of a current sampling circuit according to an embodiment of the present invention, the current sampling circuit 50 includes: at least one current sampling resistor 51, a second bypass capacitor 52 and a second filter capacitor 53 connected to the current sampling resistor 51, and a second operational amplifier 54 having one end connected to the current sampling resistor 51 and the other end outputting the current sampling signal.

[0066] The current sampling circuit 50 is used to sample the current of the DC bus circuit 20 and the AC bus circuit 30. The current sampling point 511 is as follows: Figure 2 As shown, of course, the specific selection of the current sampling point 511 can be adjusted according to actual needs, and the second operational amplifier 54 outputs a voltage sampling signal to the main control chip 70.

[0067] The current sampling circuit 50 may also be a current detection amplifier circuit or an integrated current detection circuit.

[0068] In an embodiment of the present invention, the detection module 60 includes a short-circuit detection module and an oscillation detection module; the short-circuit detection module is used to receive the current sampling signal, and judge whether the bridge switch circuit 10 is short-circuited according to the current sampling signal, and send the judgment result to the main control module 70; the oscillation detection module is used to receive the current sampling signal and the voltage sampling signal, and judge whether the switch tube of the bridge switch circuit 10 is abnormally turned on according to the current sampling signal and the voltage sampling signal, and send the judgment result to the main control module 70.

[0069] The switch tube of the bridge switch circuit 10 may be misconnected due to high-frequency oscillation or oscillation caused by AC load. The short-circuit detection module receives the current sampling signal, preliminarily determines whether the bridge switch circuit 10 is short-circuited according to the current sampling signal, and sends the judgment result to the main control module 70. The oscillation detection module receives the current sampling signal and the voltage sampling signal, and determines whether abnormal oscillation occurs, whether it causes misconnection or there is a risk of misconnection according to the current sampling signal and the voltage sampling signal, and sends the judgment result to the main control module 70.

[0070] In the embodiment of the present invention, the main control module 70 is used to stop sending pulse signals to the bridge switch circuit 10 when the switch tube of the bridge switch circuit 10 is abnormally turned on.

[0071] The main control module 70 performs pulse information control according to the judgment results sent by the short-circuit detection module and the oscillation detection module. Upon receiving the short-circuit and oscillation risk instructions, the main control chip locks the pulse signal and stops sending the pulse signal to the bridge switch circuit 10. The bridge switch circuit 10 will stop working if it does not receive the pulse signal. In this way, the switch tube can be protected in time from being damaged by the spike impact caused by the oscillation and the switch power supply can be protected from being short-circuited, thereby improving the stability and reliability of the switch power supply.

[0072] After the main control module 70 stops sending pulse signals to the bridge switch circuit 10, a self-check procedure is performed after a preset time, a pre-charge instruction is sent to the bridge switch circuit 10, the voltage sampling circuit 40 and the current sampling circuit 50 sample the voltage and current conditions on the DC bus side and the AC bus side, and the oscillation detection module and the short-circuit detection module collect and detect information. If the risk of misconduction is eliminated at this time, the main control chip sends an instruction to make the bridge switch circuit 10 start working again.

[0073] Exemplarily, the preset time may be 1 minute, and the self-check procedure may be performed after 1 minute. Of course, the preset time may be set in actual applications according to actual needs, and the embodiment of the present invention does not limit this.

[0074] Precharge instructions are critical in power electronic devices, especially electric vehicles, uninterruptible power supply (UPS) systems, and converters and inverters using large capacitors. It is a control strategy for smoothly starting high-voltage capacitors or battery packs. The main purpose is to prevent hardware damage caused by excessive inrush current at the moment of system startup. Overview of the precharge process, precharge resistor: The precharge circuit usually includes a precharge resistor (resistor) or a precharge relay, which forms a high-impedance link between the high-voltage circuit and the capacitor or battery pack. Startup phase: When the system starts, the precharge instruction connects the precharge resistor to the circuit, so that the current in the circuit will pass through the precharge resistor instead of directly to the capacitor or battery, thereby limiting the instantaneous current. Capacitor charging: The current passes through the precharge resistor and the capacitor begins to charge smoothly. During this process, the capacitor voltage gradually increases until it reaches or approaches the power supply voltage. Normal operation: When the capacitor voltage reaches a certain preset value (usually more than 90% of the power supply voltage), the precharge resistor is disconnected and the system enters normal operation. At this time, the main relay or contactor is closed, allowing the current to flow directly through the capacitor for subsequent work. Function: Protect circuit components: The pre-charging process can prevent high-voltage capacitors, battery packs or power modules from suddenly being subjected to large current shocks during cold start, reduce damage to circuit components and extend service life. Reduce voltage fluctuations: By limiting the initial current, pre-charging can smooth the startup process, avoid large fluctuations in system voltage, and improve system stability and safety. Implementation strategy Pre-charging instructions are usually executed by controller software or automatically triggered by hardware circuits. In complex power electronic systems, the pre-charging process may require precise control and monitoring to ensure that the circuit can not only start safely, but also enter an efficient and stable working state after startup. Usually, the precise execution of pre-charging instructions requires the use of current sensors and voltage sensors to monitor the circuit status, and adjust the pre-charging duration based on feedback to ensure that the capacitor or battery pack reaches normal working state smoothly.

[0075] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0076] It will be appreciated by those skilled in the art that the embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0077] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0078] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0079] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable terminal device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0080] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0081] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0082] The above is a detailed introduction to a detection circuit for abnormal conduction of a switch tube provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A detection circuit for abnormal conduction of a switch tube, characterized in that: include: A bridge switch circuit, a DC bus circuit and an AC bus circuit connected to the bridge switch circuit, a voltage sampling circuit and a current sampling circuit respectively connected to the DC bus circuit and the AC bus circuit, a detection module respectively connected to the voltage sampling circuit and the current sampling circuit, and a main control module connected to the detection module; The bridge switch circuit is used to convert the DC voltage of the DC bus circuit into an AC voltage and transmit the AC voltage to the AC bus circuit; The voltage sampling circuit is used to sample the voltages of the DC bus circuit and the AC bus circuit, and transmit the voltage sampling signals to the detection module; The current sampling circuit is used to sample the current of the DC bus circuit and the AC bus circuit, and transmit the current sampling signal to the detection module; The detection module is used to determine whether the switch tube of the bridge switch circuit is abnormally turned on according to the voltage sampling signal and the current sampling signal, and send the determination result to the main control module; The main control module is used to determine whether the switch tube of the bridge switch circuit is abnormally turned on according to the judgment result, and when the switch tube of the bridge switch circuit is abnormally turned on, control the bridge switch circuit to stop receiving the DC voltage of the DC bus circuit.

2. The circuit according to claim 1, characterized in that The DC bus circuit includes multiple capacitors and a DC bus; the DC bus includes a positive pole and a negative pole; the multiple capacitors are connected in parallel between the positive pole and the negative pole of the DC bus, and are used to transmit the DC voltage of the DC bus to the bridge switching circuit.

3. The circuit according to claim 2, characterized in that The DC bus circuit also includes a contactor; one end of the contactor is connected to the positive pole of the DC bus, and the other end is connected to the bridge switch circuit, for controlling whether the DC voltage of the positive pole of the DC bus is transmitted to the bridge switch circuit.

4. The circuit according to claim 1, characterized in that The bridge switch circuit includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; the first switch tube and the third switch tube are upper bridge switch tubes, the second switch tube and the fourth switch tube are lower bridge switch tubes, the first switch tube and the third switch tube are used to receive the DC voltage of the positive pole of the DC bus; the second switch tube and the fourth switch tube are used to receive the DC voltage of the negative pole of the DC bus.

5. The circuit according to claim 4, characterized in that The input end of the first switch tube is connected to the positive pole of the DC bus, and the output end is connected to the second switch tube; the input end of the second switch tube is connected to the negative pole of the DC bus, and the output end is connected to the fourth switch tube; the input end of the third switch tube is connected between the positive pole of the DC bus and the first switch tube, and the output end is connected to the fourth switch tube; the input end of the fourth switch tube is connected between the negative pole of the DC bus and the second switch tube, and the output end is connected to the third switch tube.

6. The circuit according to claim 5, characterized in that The bridge switch circuit includes a first output end and a second output end; the first output end is arranged between the first switch tube and the second switch tube, and is used to output the AC voltage; the second output end is arranged between the third switch tube and the fourth switch tube, and is used to output the AC voltage.

7. The circuit according to claim 6, characterized in that The AC bus circuit includes an AC bus, a first inductor and a second inductor; the AC bus includes a live wire and a neutral wire; one end of the first inductor is connected to the first output end, and the other end is connected to the live wire of the AC bus; one end of the second inductor is connected to the second output end, and the other end is connected to the neutral wire of the AC bus.

8. The circuit according to claim 1, characterized in that The voltage sampling circuit includes: at least one voltage sampling resistor, a first bypass capacitor and a first filter capacitor connected to the voltage sampling resistor, and a first operational amplifier having one end connected to the voltage sampling resistor and the other end outputting the voltage sampling signal.

9. The circuit according to claim 1, characterized in that The current sampling circuit includes: at least one current sampling resistor, a second bypass capacitor and a second filter capacitor connected to the current sampling resistor, and a second operational amplifier having one end connected to the current sampling resistor and the other end outputting the current sampling signal.

10. The circuit according to claim 1, characterized in that The detection module includes a short-circuit detection module and an oscillation detection module; the short-circuit detection module is used to receive the current sampling signal, and judge whether the bridge switch circuit is short-circuited according to the current sampling signal, and send the judgment result to the main control module; the oscillation detection module is used to receive the current sampling signal and the voltage sampling signal, and judge whether the switch tube of the bridge switch circuit is abnormally turned on according to the current sampling signal and the voltage sampling signal, and send the judgment result to the main control module.

11. The circuit according to claim 1, characterized in that The main control module is used to stop sending pulse signals to the bridge switch circuit when the switch tube of the bridge switch circuit is abnormally turned on.

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