Protection system based on pumping voltage suppression

Abstract

The invention discloses a protection system based on pumping voltage suppression, which is applied to a power conversion system and comprises a high voltage acquisition and isolation circuit, a comparison circuit, an IGBT (Insulated Gate Bipolar Transistor) single-tube switching circuit and a discharge power resistance circuit which are connected in sequence, and the high voltage acquisition and isolation circuit, the comparison circuit, the IGBT single-tube switching circuit and the discharge power resistance circuit are connected in sequence. Voltage pulses of a high-voltage power supply bus are collected through the high-voltage collection and isolation circuit, comparison processing is carried out through the comparison circuit, a switching signal is output to control the IGBT single tube switching circuit, an IGBT single tube is started, and therefore a path is provided for a power resistor, bus voltage discharge is achieved, and pumping voltage suppression is completed. According to the invention, a simple circuit structure is adopted, the pumping voltage is suppressed through the bleeder circuit, and each component in the circuit system is protected.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular, to a protection system based on pump-up voltage suppression. Background Art

[0002] In more and more servo system requirements at home and abroad, in order to protect the ground measurement power supply, or for dual-battery power supply on the projectile, requiring isolation and bus connection of two power supplies, it is necessary to add a diode at the power input end during product design. Due to the irreversibility of the diode, the energy of the motor cannot be fed back to the power grid. When the motor suddenly brakes at high speed, it will cause the voltage on the power supply bus of the power conversion circuit to rise, and this phenomenon is called "pump-up". The "pump-up" phenomenon will cause damage to GTR in the PWM system with high-voltage power supply. In order to improve the reliability of the PWM system, when designing the power supply of the power conversion circuit, the pump-up phenomenon must be suppressed.

[0003] At the initial stage of motor deceleration, the pulse width of the reverse current (the conduction time of the freewheeling diode) is longer than the action time of the forward current conducted by GTR, and these two currents are equal in value. Therefore, during the motor deceleration time, the energy storage capacitor tends to be in the "pump-up" working state. In the "pump-up" working state, the safety factor of the motor output stage and the driving transistor Uceo(sus) will be reduced, affecting the breakdown voltage of the freewheeling diode and the power rectifier diode, as well as the withstand voltage of the energy storage capacitor and all other devices connected in parallel to the power supply bus.

[0004] Therefore, whether considering improving efficiency, power supply filtering, or suppressing pump-up, increasing the energy storage capacitor is beneficial. In system design, it is necessary to predict the feedback energy and store it in an appropriate capacitor for use during the motor acceleration period, which is an ideal method. However, in industrial applications, the power supply voltage itself is very high, the structural layout space is limited, and considering the withstand voltage limitations of other components, it is necessary to adopt the method of dissipating the feedback energy instead of the method of storing the feedback energy. Existing servo mechanisms usually have a bus power supply voltage of 160V, 270V, and higher, and an energy dissipation circuit is required to discharge the high-voltage energy on the bus to protect the IGBT module and other parallel electronic components. Summary of the Invention

[0005] The present invention provides a protection system based on pump-up voltage suppression, which is applied to a power conversion circuit / PWM system, and includes: a high-voltage acquisition and isolation circuit, a comparison circuit, an IGBT single-tube switch circuit, and a discharge power resistor circuit connected in sequence;

[0006] The input end of the high-voltage acquisition and isolation circuit is connected to the power supply bus voltage, and is used to obtain the input voltage signal and input the voltage signal to the comparison circuit;

[0007] A comparison circuit for receiving the voltage signal and determining whether the voltage signal exceeds a voltage threshold. When the voltage signal exceeds the voltage threshold, a switch signal is output and sent to the opto-isolation circuit.

[0008] An IGBT single-switch circuit for receiving the switch signal. When the switch signal is a preset control signal, the IGBT single switch is controlled to be in an on state to provide a path for the discharge power resistor circuit.

[0009] The first input terminal of the discharge power resistor circuit is connected to the IGBT single-switch circuit, and the second input terminal of the discharge power resistor circuit is connected to the power supply bus voltage. It is used to short-circuit the power supply bus and the ground wire through the discharge resistor when the IGBT single switch is in the on state to achieve the discharge of the bus voltage and complete the pump-up voltage suppression.

[0010] Further, it further includes: an opto-isolation circuit. One end of the opto-isolation circuit is connected to the comparison circuit, and the other end is connected to the IGBT single-switch circuit, and is used to receive the switch signal, perform isolation and drive amplification, and then send it to the IGBT single-switch circuit.

[0011] Further, it further includes: a rail-to-rail operational amplifier proportional amplification circuit and a power supply secondary conversion circuit;

[0012] The rail-to-rail operational amplifier proportional amplification circuit is used to receive the voltage signal output by the high-voltage acquisition and isolation circuit and perform proportional amplification processing to meet the input requirements of the comparison circuit.

[0013] The power supply secondary conversion circuit is used to access the input voltage of DC + 28V and convert the input voltage into the working voltage required by the rail-to-rail operational amplifier proportional amplification circuit.

[0014] Further, the resistance value of the discharge resistor is specifically:

[0015]

[0016] Wherein, R L , is the discharge resistor, U S.max is the maximum allowable voltage, I3 is the feedback current, n N is the rated speed of the motor, K E is the motor back electromotive force constant, and R3 is the feedback resistor.

[0017] Further, the voltage threshold is at least set to 1.8 times the bus voltage value.

[0018] Further, it further includes: a discharge control delay circuit

[0019] One end of the discharge control delay circuit is connected to the optocoupler isolation circuit, and one end of the discharge control delay circuit is connected to the IGBT single-tube switch circuit, for receiving a switching signal and maintaining a switching state.

[0020] Further, it further includes: a switch drive protection circuit, one end of the switch drive protection circuit is connected to the comparison circuit, and the other end of the switch drive protection circuit is connected to the discharge power resistor circuit, for shaping the received switching signal and providing overcurrent / short-circuit protection for the IGBT single-tube switch circuit.

[0021] Further, the switch drive protection circuit includes a signal shaping circuit and an overcurrent / short-circuit protection circuit; the signal shaping circuit includes a Schmitt trigger, and the overcurrent / short-circuit protection circuit is implemented by a current detection resistor and a comparator.

[0022] The protection system based on pump-up voltage suppression provided by the embodiment of the present invention collects the input power supply bus voltage through a high-voltage acquisition and isolation circuit, and inputs the voltage signal to a comparison circuit. If the voltage exceeds a preset voltage threshold, the comparison circuit outputs a high-level switching signal to turn on the IGBT single-tube switch circuit, so that one end of the discharge power resistor circuit is at a high level, and then the other end of the discharge power resistor circuit is pulled down from the high level, and finally the power supply bus is short-circuited to the ground wire, realizing the discharge of the bus voltage and completing the suppression of the pump-up voltage. When it is judged that the pump-up voltage exceeds the preset voltage threshold, the pump-up voltage is discharged, achieving the effect of rapid decline of the output voltage when suppressing the pump-up voltage, effectively protecting and preventing damage to electronic components in the power conversion circuit / PWM system caused by too high pump-up voltage, realizing the rapid suppression of the pump-up voltage, improving the stability and reliability of the system, and having high safety and reliability and low cost.

[0023] The optocoupler isolation circuit plays an isolation and drive amplification role between the comparison circuit and the IGBT single-tube switch circuit. On the one hand, it can avoid signal interference and ensure the accuracy of signal transmission; on the other hand, it can enhance the drive ability and ensure that the IGBT single tube can be reliably turned on and off. The rail-to-rail operational amplifier proportional amplification circuit can perform proportional amplification processing on the voltage signal output by the high-voltage acquisition and isolation circuit to meet the input requirements of the comparison circuit. The power supply secondary conversion circuit provides the required working voltage for the rail-to-rail operational amplifier proportional amplification circuit. Ensure that the voltage signal can be accurately compared and processed, and at the same time ensure that the relevant circuits have a stable working voltage.

[0024] Through precise calculation of the discharge resistor value, the resistance value calculation formula of the discharge resistor takes into account parameters such as the maximum allowable voltage, feedback current, rated motor speed, motor back electromotive force constant, and feedback resistor. It can accurately determine the resistance value of the discharge resistor according to the actual operating parameters of the system, ensuring the effectiveness and safety of the discharge process.

[0025] The switch drive protection circuit shapes the switch signal output by the comparison circuit and provides overcurrent / short-circuit protection for the IGBT single-tube switch circuit. The discharge control delay circuit can receive the switch signal and maintain the switch state for a certain period of time, further improving the safety and reliability of the system, preventing faults such as overcurrent and short-circuit from damaging the IGBT single tube and the entire system, and ensuring the stable progress of the discharge process through delay control. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 is one of the structural schematic diagrams of the protection system based on pump-up voltage suppression provided by the embodiments of the present invention;

[0028] Figure 2 is the second of the structural schematic diagrams of the protection system based on pump-up voltage suppression provided by the embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention fall within the scope of protection of the present invention.

[0030] It should be noted that in the description of the embodiments of the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element. The orientation or positional relationship indicated by terms such as "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. Unless otherwise clearly specified and defined, the terms "mount", "connect", "couple" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] The terms "first", "second", etc. in this application are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of this application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same category and do not limit the number of objects. For example, the first object can be one or multiple. In addition, "and / or" means at least one of the connected objects, and the character " / ", generally represents an "or" relationship between the associated objects before and after.

[0032] When the motor suddenly decelerates during high-speed rotation, a part of the kinetic energy stored in the rotating armature and the load will be fed back to the power conversion circuit. And the stored energy often exceeds the energy required for the motor to decelerate, and during this deceleration period, the motor will transfer energy to the power conversion circuit. When the motor decelerates, at the initial stage of deceleration, the pulse width of the reverse current (the conduction time of the freewheeling diode) is longer than the action time of the forward current conducted by the GTR, and these two currents are equal in value. Therefore, the energy storage capacitor tends to be in a "pump-up" operating state during the deceleration of the motor. In the "pump-up" operating state, the safety factor of the system output stage and the driving transistor Uceo(sus) will be reduced, affecting the breakdown voltage of the freewheeling diode and the power rectifier diode, as well as the withstand voltage of the energy storage capacitor and all other devices connected in parallel to the power bus.

[0033] The following will combine with Figure 1 - Figure 2 to describe the protection system provided by the embodiments of the present invention based on pump-up voltage suppression.

[0034] Figure 1 is one of the structural schematic diagrams of the protection system provided by the present invention based on pump-up voltage suppression. As Figure 1 shown, the embodiments of the present invention provide a protection system based on pump-up voltage suppression, which is applied to a power conversion circuit / PWM system, and includes: a high-voltage acquisition and isolation circuit, a comparison circuit, an IGBT single-tube switching circuit, and a discharge power resistor circuit that are connected in sequence;

[0035] The input end of the high-voltage acquisition and isolation circuit is connected to the power supply bus voltage, and is used to acquire the input voltage signal and input the voltage signal to the comparison circuit;

[0036] The comparison circuit is used to receive the voltage signal and determine whether the voltage signal exceeds a preset voltage threshold. When the voltage signal exceeds the preset voltage threshold, it outputs a switching signal and sends the switching signal to the optocoupler isolation circuit;

[0037] The IGBT single-tube switching circuit is used to receive the switching signal. When the switching signal is a preset control signal, it controls the IGBT single tube to be in an on state according to the switching signal to provide a path for the discharge power resistor circuit;

[0038] The discharge power resistor circuit is used to short-circuit the power supply bus and the ground wire through the discharge power resistor circuit when the IGBT single tube is in an on state to realize the discharge of the bus voltage and complete the pump-up voltage suppression.

[0039] In this embodiment, a protection system based on pump-up voltage suppression proposed by the present invention is applied to a power conversion circuit / PWM system. First, the high-voltage acquisition and isolation circuit acquires the voltage signal of the power supply bus and inputs the voltage signal to the comparison circuit. The comparison circuit receives the voltage signal and determines whether the voltage signal exceeds the preset voltage threshold. When the voltage signal exceeds the preset voltage threshold, the comparison circuit outputs a switching signal. The switching signal will be input to the optocoupler isolation circuit for isolation and drive amplification processing and output to the IGBT single-tube switching circuit. The IGBT single-tube switching circuit will receive the switching signal output by the optocoupler isolation circuit. When the switching signal is a preset control signal, the IGBT single-tube switching circuit controls the IGBT single tube to turn on. The turn-on of the IGBT single tube can short-circuit the power supply bus and the ground wire through the discharge power resistor circuit, thereby completing the pump-up voltage suppression protection. Through a simple circuit structure, the rapid suppression of the pump-up voltage is realized, and the safety and reliability are high, and the cost is low.

[0040] In a preferred embodiment, it further includes: an optocoupler isolation circuit, one end of the optocoupler isolation circuit is connected to the comparison circuit, and the other end of the optocoupler isolation circuit is connected to the IGBT single transistor switching circuit, for receiving the switching signal, isolating and driving amplification, and then sending it to the IGBT single transistor switching circuit.

[0041] Specifically, the high-voltage acquisition and isolation circuit can be composed of a high-precision voltage sensor and an isolation amplifier. The voltage sensor can accurately acquire the power supply bus voltage. The isolation amplifier uses optoelectronic coupling technology to achieve electrical isolation between the input side and the output side. The voltage sensor real-time obtains the power supply bus voltage signal and transmits it to the isolation amplifier. After the isolation amplifier performs isolation processing on the voltage signal, it outputs to the comparison circuit. This process ensures that when collecting high-voltage signals, it will not cause electrical interference to the subsequent circuits.

[0042] The comparison circuit can use a high-speed comparator with a response time less than 10 ns. The positive input terminal of the comparator receives the voltage signal output by the high-voltage acquisition and isolation circuit, and the negative input terminal is connected to a reference voltage source, which can be set to 1.8 times the bus voltage value, that is, the voltage threshold. When the voltage signal output by the high-voltage acquisition and isolation circuit exceeds the voltage threshold, the comparator outputs a high-level switching signal. This signal indicates that the bus voltage has a pumping phenomenon and the discharge mechanism needs to be started.

[0043] The optocoupler isolation circuit can select an optocoupler device with a high isolation voltage and a high current transfer ratio. Its input side is connected to the output terminal of the comparison circuit, and the output side is connected to the IGBT single transistor switching circuit. The optocoupler isolation circuit receives the switching signal output by the comparison circuit, and realizes signal isolation and drive amplification through optoelectronic conversion. The amplified signal is transmitted to the IGBT single transistor switching circuit to ensure reliable signal transmission.

[0044] The IGBT single transistor switching circuit can use an IGBT single transistor with a rated voltage of 1200V and a rated current of 50A for example. The gate of the IGBT single transistor is connected to the output terminal of the optocoupler isolation circuit through a resistor, the drain is connected to the discharge power resistor circuit, and the source is grounded. When the IGBT single transistor switching circuit receives the high-level switching signal output by the optocoupler isolation circuit, the IGBT single transistor conducts, providing a path for the discharge power resistor circuit.

[0045] The discharge power resistor circuit can include a high-power discharge resistor. It should be noted that the resistance value of the discharge resistor is calculated according to the system parameters, and the resistance value of the discharge resistor is specifically:

[0046]

[0047] Among them, R L , is the discharge resistor, US.max is the maximum allowable voltage, I3 is the feedback current, n N is the rated speed of the motor, K E is the back electromotive force constant of the motor, and R3 is the feedback resistor. The resistance value calculation formula of the discharge resistor provided by the present invention takes into account parameters such as the maximum allowable voltage, feedback current, rated speed of the motor, back electromotive force constant of the motor, and feedback resistor, and can accurately determine the resistance value of the discharge resistor according to the actual operating parameters of the system, ensuring the effectiveness and safety of the discharge process.

[0048] When the IGBT single tube is turned on, the discharge resistor shorts the power supply busbar to the ground wire to achieve the discharge of the busbar voltage. For example, when the busbar voltage rises to 1000V due to pump-up, the voltage is quickly discharged through the discharge resistor to prevent damage to the system caused by excessive voltage.

[0049] When the voltage sampling signal output by the voltage acquisition and isolator circuit is greater than the set threshold value, the isolation control IGBT tube located in the feedback branch is turned on, and the busbar voltage of the power switch circuit is directly shorted to the ground to achieve rapid suppression of the pump-up voltage. When the current signal input to the power module is higher than the set threshold value of the power circuit current, the switch drive protection circuit provides overcurrent / short-circuit protection to turn off the flyback switch, thereby achieving short-circuit protection of the power switch circuit, and realizing DC isolation of the circuit through the isolator.

[0050] In a preferred embodiment, Figure 2 is the second schematic diagram of the structure of the protection system based on pump-up voltage suppression provided by the present invention, as Figure 2 shown, in the protection system based on pump-up voltage suppression provided in this embodiment, it further includes: a rail-to-rail operational amplifier proportional amplification circuit and a power supply secondary conversion circuit;

[0051] The rail-to-rail operational amplifier proportional amplification circuit is used to receive the voltage signal output by the high-voltage acquisition and isolation circuit for proportional amplification processing to meet the input requirements of the comparison circuit.

[0052] The power supply secondary conversion circuit is used to access the input voltage of DC + 28V and convert the input voltage into the working voltage required by the rail-to-rail operational amplifier proportional amplification circuit.

[0053] Specifically, the rail-to-rail operational amplifier proportional amplification circuit can adopt a high-precision operational amplifier with an input offset voltage less than 1mV. A plurality of precision resistors are provided in the circuit to achieve the proportional amplification function. This circuit receives the voltage signal output by the high-voltage acquisition and isolation circuit, and through the cooperation of the precision resistor and the operational amplifier, the voltage signal is subjected to proportional amplification processing to meet the input requirements of the comparison circuit. For example, the input voltage signal of 0 - 5V is amplified to 0 - 10V to ensure that the comparison circuit can accurately judge whether the voltage exceeds the threshold.

[0054] The secondary power conversion circuit mainly consists of a DC-DC converter, and its input voltage can be, for example, DC + 28V. The converter internally uses a high-frequency transformer and a voltage stabilizing circuit, which can convert the input voltage into the ±15V operating voltage required by the rail-to-rail operational amplifier proportional amplification circuit. After the DC + 28V input voltage enters the secondary power conversion circuit, it undergoes voltage transformation through the high-frequency transformer and then outputs a stable ±15V operating voltage through the voltage stabilizing circuit, providing a reliable power supply for the rail-to-rail operational amplifier proportional amplification circuit.

[0055] Furthermore, a protection system based on pump-up voltage suppression provided by the present invention further includes a switch drive protection circuit, which can include a signal shaping circuit and an overcurrent / short-circuit protection circuit. The signal shaping circuit is composed of a Schmitt trigger, and the overcurrent / short-circuit protection circuit is implemented using a current detection resistor and a comparator. The signal shaping circuit shapes the switch signal output by the comparison circuit to ensure that the rising edge and falling edge of the signal are steeper, facilitating the reliable triggering of the IGBT single transistor. The overcurrent / short-circuit protection circuit monitors the current of the IGBT single transistor in real time. When the current exceeds the set threshold, it quickly turns off the IGBT single transistor to prevent it from being damaged.

[0056] Furthermore, a protection system based on pump-up voltage suppression provided by the present invention further includes a discharge control delay circuit, which consists of a monostable flip-flop, a capacitor, and a resistor. The trigger input terminal of the monostable flip-flop is connected to the output terminal of the opto-isolation circuit, and the output terminal is connected to the IGBT single transistor switch circuit. When the opto-isolation circuit outputs a switch signal, the monostable flip-flop is triggered and outputs a high-level signal for a certain period of time (for example, 100 μs) to ensure that the IGBT single transistor remains in the on state during this period and realizes a stable discharge process.

[0057] The present invention adopts a design scheme of "isolated operational amplifier + comparator + opto-isolation + IGBT single transistor + discharge resistor". In terms of the structural layout, the voltage detection, comparison, and isolation of the weak current part are all arranged on the drive board, increasing the electrical distance from the strong current part circuit and reducing electromagnetic radiation interference; on the other hand, the gate drive adopts opto-isolation to achieve the electrical isolation design between the strong and weak currents, avoiding the conduction interference between the strong and weak currents. Through the collaborative work of the above-mentioned circuits, when the bus voltage shows a pump-up phenomenon, the system can quickly and accurately start the discharge mechanism, effectively preventing damage to the system electronic components caused by excessive pump-up voltage.

[0058] During the implementation process of the present invention, the present invention also provides an effective and feasible calculation method for discharge resistor selection and threshold setting and a waveform measurement method. Through testing, the consistency between the actual effect and the theoretical calculation is proved, and finally the design work of the braking system protection module is completed.

[0059] Meanwhile, effective PCB layout and wiring rules and assembly process requirements are proposed to effectively reduce the system volume and weight and achieve a good braking system protection effect.

[0060] Specifically as follows:

[0061] a) Calculation methods for the selection of discharge resistors and the setting of thresholds;

[0062] 1) The input signal of the isolation op-amp "N" should not be greater than 2V. When it exceeds 2V, the output is non-linear with the input, and when it exceeds 2.4V, it will cause damage to the isolation op-amp "N";

[0063] 2) The threshold voltage is set to 1.8 times the bus voltage value or higher;

[0064] Specifically, it shall be subject to the actual application; communication with the overall system is required here to confirm the maximum battery output voltage to avoid setting the threshold voltage too low, resulting in the pump-up suppression circuit working in overcurrent for a long time and damaging the IGBT single tube and the discharge resistor;

[0065] b) Waveform measurement methods;

[0066] During waveform measurement, the sampling value at both ends of the voltage-dividing resistor (input of GlaC87AP) shall be used as the standard, and a parallel capacitor is required to filter its signal, which can improve the quality of the switch signal switch and avoid frequent useless opening and closing of the optocoupler. However, adding a filtering capacitor will cause a delay in the subsequent signal, manifested as the actual opening voltage being larger than the threshold voltage. The larger the capacitance value, the more obvious this phenomenon is. Therefore, it is generally recommended that the capacitance value here should not exceed 0.1uF;

[0067] c) The rated voltage of all power devices in this circuit shall be above 3 times the bus voltage. The rated voltage of the power device shall be greater than the voltage value at the most severe working state of the product, that is, the highest pump-up voltage value during the maximum angle step signal test of all servos simultaneously;

[0068] d) IGBT single-tube current calculation and discharge resistor power calculation;

[0069] 1) The two complement each other and need to be considered simultaneously. When the discharge resistor has a small resistance value, the voltage discharge effect is good, but the current flowing through the circuit is large, requiring high power for the resistor and the rated current of the IGBT single tube; when the power resistor has a large resistance value, the voltage discharge effect is poor, the discharge time will be long, and the power requirement for the resistor is also high, and it has a greater impact on the performance of the entire servo mechanism;

[0070] 2) The power resistor is calculated according to the energy J. The cumulative power-on time and heat must be considered here.

[0071] The design margin is considered at least according to: applying a square wave signal with the maximum angle for 5 cycles simultaneously to all servos. For example, in the 1K37-19 servo mechanism, the power resistors are two in parallel, each with a resistance value of 22 Ω, and the parallel resistance value is 11 Ω. When the voltage pump-up suppression circuit works, assuming the highest pump-up voltage is 380 V, the current flowing through the two resistors is 380 V / 11 Ω = 34.1 A; when the pump-up circuit works during a single servo braking, the working time is calculated as 2 ms. The energy formula is Q = I²Rt. The energy generated on a single resistor in 5 cycles is: Q = (17.05)² * 22 Ω * 0.002 s * 10 times = 127.9 J, which is within the rated value range of the two discharge resistors (160 J) and there is a margin;

[0072] 3) The four-way actuators respond to a 25° step signal simultaneously.

[0073] 4) It should be clearly stated in the product instruction manual and the precautions in the technical conditions that the servo mechanism cannot continuously perform a maximum angle square wave signal test for more than 5 cycles;

[0074] e) PCB layout and wiring method:

[0075] The pump-up suppression circuit is an isolation circuit. When laying out its control part, attention should be paid to separating it from the power part to avoid confusion; the IGBT single tube needs to be installed with the case attached and the wiring loop should be as short as possible, and good heat dissipation should be considered; the filter capacitors at both ends of the voltage-dividing resistor (input of GlaC87AP) should be as close as possible to the chip pins; all chip decoupling capacitors should be as close as possible to the chip pins;

[0076] f) Assembly process requirements:

[0077] For the IGBT single tube, the case screws need to be fixed first and then welded; a non-alkali glass fiber cloth interlayer is required between the discharge resistor and the printed circuit board to prevent the power resistor from burning and scalding the printed circuit board; for the discharge resistor, a small amount of glue should be applied between the body and the printed circuit board and tied with a binding wire. Gluing at the legs is prohibited as it will affect the heat dissipation effect;

[0078] g) Test requirements: Isolation probes are required for power part testing and control part testing, and they cannot be grounded; during the test, lead out the monitoring points to avoid electric shock.

[0079] h) The power supply of the input terminal of the isolation op-amp "N" needs to rise monotonically from 0 V and should not show a drop, otherwise it will cause abnormal output.

[0080] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0081] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protection system based on pump-up voltage suppression, applied to a power conversion circuit / PWM system, characterized in that: include: A high voltage collection and isolation circuit, a comparison circuit, an IGBT single-tube switch circuit and a discharge power resistor circuit connected in sequence; The input end of the high voltage acquisition and isolation circuit is connected to the power supply bus voltage to obtain an input voltage signal and input the voltage signal to the comparison circuit; A comparison circuit, used for receiving the voltage signal and determining whether the voltage signal exceeds a voltage threshold, and outputting a switch signal when the voltage signal exceeds the voltage threshold, and sending the switch signal to the optocoupler isolation circuit; An IGBT single-tube switch circuit, used for receiving the switch signal, and when the switch signal is a preset control signal, controlling the IGBT single tube to be in an on state according to the switch signal to provide a path for a discharge power resistor circuit; The first input end of the discharge power resistor circuit is connected to the IGBT single-tube switch circuit, and the second input end of the discharge power resistor circuit is connected to the power supply bus voltage, which is used to short-circuit the power supply bus and the ground wire through the discharge resistor when the IGBT single tube is in the on state, so as to realize the discharge of the bus voltage and complete the pump-up voltage suppression.

2. The protection system based on pump-up voltage suppression according to claim 1, characterized in that: Also includes: An optocoupler isolation circuit, one end of which is connected to the comparison circuit, and the other end of which is connected to the IGBT single-tube switch circuit, is used to receive the switch signal for isolation and drive amplification and then send it to the IGBT single-tube switch circuit.

3. The protection system based on pump-up voltage suppression according to claim 2, characterized in that: Also includes: Rail-to-rail operational amplifier proportional amplifier circuit and power secondary conversion circuit; The rail-to-rail operational amplifier proportional amplification circuit is used to receive the voltage signal output by the high voltage acquisition and isolation circuit and perform proportional amplification processing so that it meets the input requirement of the comparison circuit. The power secondary conversion circuit is used to receive the DC+28V input voltage and convert the input voltage into the operating voltage required by the rail-to-rail operational amplifier proportional amplification circuit.

4. The protection system based on pump-up voltage suppression according to claim 1, characterized in that: The resistance value of the discharge resistor is specifically: Among them, R L , is the discharge resistance, U S.max is the maximum allowable voltage, I3 is the feedback current, n N is the rated speed of the motor, K E is the motor back electromotive force constant, and R3 is the feedback resistor.

5. The protection system based on pump-up voltage suppression according to claim 1, characterized in that: The voltage threshold is set to at least 1.8 times the bus voltage value.

6. The protection system based on pump-up voltage suppression according to claim 1, characterized in that: Also includes: Discharge control delay circuit, One end of the discharge control delay circuit is connected to the optocoupler isolation circuit, and one end of the discharge control delay circuit is connected to the IGBT single-tube switch circuit, for receiving a switch signal and maintaining a switch state.

7. The protection system based on pump-up voltage suppression according to claim 1, characterized in that: Also includes: A switch drive protection circuit, one end of the switch drive protection circuit is connected to the comparison circuit, and the other end of the switch drive protection circuit is connected to the discharge power resistance circuit, which is used to shape the received switch signal and provide overcurrent / short circuit protection for the IGBT single-tube switch circuit.

8. The protection system based on pump-up voltage suppression according to claim 1, characterized in that: The switch drive protection circuit comprises a signal shaping circuit and an overcurrent / short circuit protection circuit; the signal shaping circuit comprises a Schmitt trigger; the overcurrent / short circuit protection circuit is implemented by a current detection resistor and a comparator.

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