High-voltage isolation control system

Abstract

The invention relates to the technical field of communication, and particularly discloses a high-voltage isolation control system, which comprises a high-voltage side control module connected with a high-voltage side communication module, a low-voltage side control module connected with a low-voltage side communication module, and a first transmitting unit, a second receiving unit and a third receiving unit, the high-voltage side communication module comprises a first receiving unit, a second transmitting unit and a third transmitting unit, the first transmitting unit and the first receiving unit are connected with each other through an optical fiber, and the second transmitting unit and the second receiving unit are connected with each other through an optical fiber; and the third transmitting unit and the third receiving unit are connected with each other through the optical fiber. And signals between the high-voltage side and the low-voltage side are bidirectionally transmitted through the optical fiber, so that full-electrical isolation is realized. By designing three sets of signal receiving and transmitting units, low-cost and high-reliability high-voltage isolation control of three channels (receiving / transmitting / enabling) can be stably realized.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage electrical isolation control, and particularly to a high-voltage isolation control system applied to the power supply system of a field emission electron gun in a transmission electron microscope. Background Art

[0002] The field emission gun (FEG) in a transmission electron microscope (TEM) is a high-performance electron source that can provide a smaller electron beam spot and higher brightness, thereby achieving higher resolution. The power supply for the field emission gun in a transmission electron microscope is usually divided into a high-voltage side and a low-voltage side, each responsible for different functions. In practical applications, effective electrical isolation is required between the high-voltage side and the low-voltage side to avoid the high voltage affecting the safety and performance of the low-voltage control circuit. In the existing technical solutions, the withstand voltage of the optocoupler isolation scheme is usually lower than 50 kV, and the control system between the high-voltage side and the low-voltage side is difficult to withstand the extreme high-voltage environment, resulting in a risk of damage to the control system during discharge. Summary of the Invention

[0003] Based on this, in view of the problem that the control system between the high-voltage side and the low-voltage side in the existing technical solutions is difficult to withstand the extreme high-voltage environment, it is necessary to provide a high-voltage isolation control system that can achieve reliable communication under a potential difference of -200 kV.

[0004] A high-voltage isolation control system includes a high-voltage side control module, a high-voltage side communication module, a low-voltage side control module, and a low-voltage side communication module. The high-voltage side control module is connected to the high-voltage side communication module, and the low-voltage side control module is connected to the low-voltage side communication module. The low-voltage side communication module includes a first sending unit, a second receiving unit, and a third receiving unit. The high-voltage side communication module includes a first receiving unit, a second sending unit, and a third sending unit. The first sending unit and the first receiving unit are interconnected by an optical fiber, the second sending unit and the second receiving unit are interconnected by the optical fiber, and the third sending unit and the third receiving unit are interconnected by the optical fiber. The low-voltage side control module transmits a low-voltage side signal to the first receiving unit through the first sending unit, the first receiving unit transmits the low-voltage side signal to the high-voltage side control module, the high-voltage side control module transmits an enable signal to the third receiving unit through the third sending unit, the third receiving unit transmits the enable signal to the low-voltage side control module, the high-voltage side control module transmits a high-voltage side signal to the second receiving unit through the second sending unit, and the second receiving unit transmits the high-voltage side signal to the low-voltage side control module.

[0005] In one embodiment, an RS485 physical interface is adopted between the high-voltage side communication module and the low-voltage side communication module, and the application layer protocol between the high-voltage side communication module and the low-voltage side communication module is Modbus RTU.

[0006] In one embodiment, the low-voltage side control module includes a low-voltage side main control unit, which is used to output the low-voltage side signal and also used to receive the enable signal or the high-voltage side signal; a communication conversion unit, connected to the low-voltage side main control unit, which is used to convert the low-voltage side signal into a signal adapted to RS485 transmission; a first level conversion unit, respectively connected to the communication conversion unit and the low-voltage side communication module, which is used to perform level conversion on the signal output by the communication conversion unit or the signal output by the low-voltage side communication module.

[0007] In one embodiment, the communication conversion unit includes two connected RS485 chips.

[0008] In one embodiment, the two RS485 chips are connected by twisted pair.

[0009] In one embodiment, the high-voltage side control module includes a high-voltage side main control unit, which is used to output the enable signal or the high-voltage side signal and also used to receive the low-voltage side signal; a second level conversion unit, respectively connected to the high-voltage side main control unit and the high-voltage side communication module, which is used to perform level conversion on the signal output by the high-voltage side main control unit or the signal output by the high-voltage side communication module.

[0010] In one embodiment, the circuit structures of the first transmitting unit, the second transmitting unit, and the third transmitting unit are the same. The first transmitting unit includes an optical fiber transmitter, a first capacitor, a first diode, a second diode, a third diode, a first resistor, and a second resistor. Among them, the optical fiber transmitter is an infrared optical fiber transmitting device with a wavelength of 600 nm to 1310 nm and a maximum transmission rate of 5 Mbps; the first diode and the second diode are transient voltage suppression diodes for clamping the voltage at the input pin of the optical fiber transmitter; the third diode is a Schottky diode for accelerating the signal edge; the first pin of the optical fiber transmitter is connected to a first voltage source and the first end of the first capacitor, the second end of the first capacitor is connected to the reference ground, the first pin of the optical fiber transmitter is also respectively connected to the negative electrodes of the first diode and the second diode, the second pin of the optical fiber transmitter is respectively connected to the positive electrode of the second diode and the first end of the second resistor, the second end of the second resistor is respectively connected to the positive electrode of the first diode, the negative electrode of the third diode, and the first end of the first resistor, the second end of the first resistor is connected to the low-voltage side control module or the high-voltage side control module, and the positive electrode of the third diode is connected to the reference ground.

[0011] In one embodiment, the circuit structures of the first receiving unit, the second receiving unit, and the third receiving unit are the same. The first receiving unit includes an optical fiber receiver, a second capacitor, a fourth diode, a fifth diode, a third resistor, and a fourth resistor. Among them, the optical fiber receiver is an infrared optical fiber receiving device with a wavelength of 600 nm to 1310 nm and a maximum transmission rate of 5 Mbps; the fourth diode is a transient voltage suppression diode for clamping the voltage at the input pin of the optical fiber receiver; the fifth diode is a Schottky diode for accelerating the signal edge; the first pin and the fourth pin of the optical fiber receiver are both connected to the first end of the third resistor, the second end of the third resistor is respectively connected to the positive electrode of the fourth diode, the negative electrode of the fifth diode, and the first end of the fourth resistor, the second end of the fourth resistor is connected to the low-voltage side control module or the high-voltage side control module, the second pin of the optical fiber receiver and the positive electrode of the fifth diode are both connected to the reference ground, the third pin of the optical fiber receiver is respectively connected to a first voltage source, the negative electrode of the fourth diode, and the first end of the second capacitor, and the second end of the second capacitor is connected to the reference ground.

[0012] In one embodiment, the circuit structures of the first level conversion unit and the second level conversion unit are the same. The first level conversion unit includes a level conversion chip, a third capacitor, a fourth capacitor, a fifth resistor, and a sixth resistor. The input-side power supply voltage pin of the level conversion chip is connected to a first voltage source, and the output-side power supply voltage pin of the level conversion chip is connected to a second voltage source, or the input-side power supply voltage pin of the level conversion chip is connected to the second voltage source, and the output-side power supply voltage pin of the level conversion chip is connected to the first voltage source. The input-side power supply voltage pin of the level conversion chip is connected to the first end of the third capacitor, and the second end of the third capacitor is connected to the reference ground. The output-side power supply voltage pin of the level conversion chip is connected to the first end of the fourth capacitor, and the second end of the fourth capacitor and the ground pin of the level conversion chip are both connected to the reference ground. The output enable pin of the level conversion chip is respectively connected to the first end of the fifth resistor and the first end of the sixth resistor. The second end of the fifth resistor is connected to the reference ground, and the second end of the sixth resistor is connected to the first voltage source or the second voltage source.

[0013] In one embodiment, the reference ground of the high-voltage side control module and the high-voltage side communication module is -200 kV, and the reference ground of the low-voltage side control module and the low-voltage side communication module is the ground.

[0014] In the above high-voltage isolation control system, there are a high-voltage side control module, a high-voltage side communication module, a low-voltage side control module, and a low-voltage side communication module. The high-voltage side control module is connected to the high-voltage side communication module, and the low-voltage side control module is connected to the low-voltage side communication module. The low-voltage side control module can transmit the low-voltage side signal to the first receiving unit of the high-voltage side communication module through the first sending unit of the low-voltage side communication module, and the first receiving unit transmits the low-voltage side signal to the high-voltage side control module. The high-voltage side control module can transmit the enable signal to the third sending unit through the third sending unit of the high-voltage side communication module, and the third sending unit transmits the enable signal to the low-voltage side control module. The high-voltage side control module can also transmit the high-voltage side signal to the second sending unit through the second sending unit of the high-voltage side communication module, and the second sending unit transmits the high-voltage side signal to the low-voltage side control module. The signals between the high-voltage side and the low-voltage side are transmitted bidirectionally through optical fibers to achieve full electrical isolation and avoid electromagnetic interference. By designing three sets of signal transceiver units, a low-cost and highly reliable high-voltage isolation control for three-channel (receiving / sending / enabling) full isolation communication can be stably achieved. Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in this specification. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic structural diagram of a high-voltage isolation control system in one embodiment of the present application; Figure 2 It is a schematic structural diagram of a low-voltage side control module in one embodiment of the present application; Figure 3 It is a schematic structural diagram of a high-voltage side control module in one embodiment of the present application; Figure 4 It is a schematic circuit connection diagram between a low-voltage side communication module and a high-voltage side communication module in one embodiment of the present application; Figure 5 It is a schematic circuit structure diagram of a first level conversion unit in one embodiment of the present application; Figure 6 It is a schematic circuit structure diagram of a high-voltage isolation control system in one embodiment of the present application. Detailed implementation manners

[0017] To facilitate the understanding of the present invention, the following will describe the present invention more comprehensively with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to understand the disclosure of the present invention more thoroughly and comprehensively.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0019] Figure 1 It is a schematic structural diagram of a high-voltage isolation control system in one embodiment of the present application. In one embodiment, the high-voltage isolation control system may include a high-voltage side control module 100, a high-voltage side communication module 200, a low-voltage side control module 300, and a low-voltage side communication module 400. The high-voltage side control module 100 is connected to the high-voltage side communication module 200, and the low-voltage side control module 300 is connected to the low-voltage side communication module 400.

[0020] Among them, the low-voltage side communication module 400 may include a first transmission unit 410, a second reception unit 420, and a third reception unit 430, and the high-voltage side communication module 200 may include a first reception unit 210, a second transmission unit 220, and a third transmission unit 230. The first transmission unit 410 and the first reception unit 210 may be interconnected through the optical fiber 10, the second transmission unit 220 and the second reception unit 420 may be interconnected through the optical fiber 10, and the third transmission unit 230 and the third reception unit 430 are interconnected through the optical fiber 10.

[0021] The low-voltage side control module 300 may be configured to output a low-voltage side signal and transmit it to the first transmission unit 410. The first transmission unit 410 may be configured to convert the low-voltage side signal into an optical signal and transmit it through the optical fiber 10 to the first reception unit 210, and the first reception unit 210 may be configured to convert the received optical signal into a low-voltage side signal and transmit it to the high-voltage side control module 100.

[0022] When the high-voltage side sends a signal to the low-voltage side, it first issues an enable signal and then further realizes the signal transmission from the high-voltage side to the low-voltage side. The high-voltage side control module 100 may be configured to output an enable signal and transmit it to the third transmission unit 230. The third transmission unit 230 converts the enable signal into an optical signal and transmits it through the optical fiber 10 to the third reception unit 430, and the third reception unit 430 may be configured to convert the received optical signal into an enable signal and transmit it to the low-voltage side control module 300. The high-voltage side control module 100 may also be configured to output a high-voltage side signal and transmit it to the second transmission unit 220. The second transmission unit 220 may convert the high-voltage side signal into an optical signal and transmit it through the optical fiber 10 to the second reception unit 420. The second reception unit 420 may convert the received optical signal into a high-voltage side signal and transmit it to the low-voltage side control module 300.

[0023] In the above high-voltage isolation control system, it can be used to realize the isolated communication control between the low-voltage side control module 300 on the low-voltage side and the high-voltage side control module 100 on the high-voltage side. The signals between the high-voltage side and the low-voltage side are transmitted bidirectionally through the optical fiber 10 to achieve full electrical isolation, and the withstand voltage level exceeds -200 kV to avoid electromagnetic interference. By designing three sets of signal transceiver units, it can stably achieve the low-cost and high-reliability high-voltage isolation control of three-channel (reception / transmission / enable) full isolation communication.

[0024] In one embodiment, the communication protocol between the high-voltage side communication module 200 and the low-voltage side communication module 400 is the Modbus RTU protocol based on RS485. RS485 is a differential signal standard that can effectively resist common-mode noise interference. At the same time, reusing the existing Modbus RTU protocol stack based on RS485 avoids the need to develop a new complex protocol, thereby reducing the overall complexity and cost of the system. In addition, since the RS485 physical layer technology is mature and stable, there are a large number of off-the-shelf components available in the market, which helps to improve the reliability and stability of the system. It can be seen that implementing communication between the low-voltage side and the high-voltage side based on the RS485 communication protocol can meet the strict requirements of the high-voltage isolation communication device for reliability and anti-interference performance.

[0025] Most of the existing solutions use 2 optical fibers to achieve automatic transceiver between the high-voltage side and the low-voltage side, eliminating the enable control. Considering the particularity of the application scenario of the transmission electron microscope field emission electron gun power supply system, in this embodiment, the communication protocol between the high-voltage side communication module 200 and the low-voltage side communication module 400 is the Modbus RTU protocol based on RS485. The low-voltage side main control unit 310 sends a signal, and the high-voltage side main control unit 110 can receive it automatically; when the low-voltage side main control unit 310 receives the signal from the high-voltage side main control unit 110, the high-voltage side main control unit 110 first sends an enable signal to the low-voltage side main control unit 310. After the low-voltage side main control unit 310 confirms the enable signal, the low-voltage side main control unit 310 can receive the signal sent by the high-voltage side main control unit 110. The high-voltage isolation control system provided by this application adopts the response mechanism of the Modbus RTU protocol based on RS485, rather than automatic transceiver, improving the reliability of communication.

[0026] Figure 2 It is a schematic structural diagram of the low-voltage side control module in one embodiment of this application. In one embodiment, the low-voltage side control module 300 may include a low-voltage side main control unit 310, a communication conversion unit 320, and a first level conversion unit 330.

[0027] The low-voltage side main control unit 310 can be used to output low-voltage side signals, and the low-voltage side main control unit 310 can also be used to receive enable signals or high-voltage side signals. In this embodiment, the low-voltage side main control unit 310 may be a main MCU (Microcontroller Unit, single-chip microcomputer). The main MCU can be used to initiate and control signals. The main MCU is responsible for initiating communication requests and sending low-voltage side signals. For example, in the control application of the transmission electron microscope field emission electron gun power supply system, the main MCU can issue commands for adjusting or querying the high-voltage side status.

[0028] The communication conversion unit 320 can be connected to the low-voltage side main control unit 310. The communication conversion unit 320 can be used to convert the low-voltage side signal into a signal suitable for RS485 transmission to achieve half-duplex RS485 communication. The communication conversion unit 320 can be used to convert between TTL / CMOS logic levels and RS485 bus differential signals, thereby realizing serial communication between devices. That is, the communication conversion unit 320 can convert TTL / CMOS logic levels into RS485 bus differential signals, and can also convert RS485 bus differential signals into TTL / CMOS logic levels.

[0029] The first level conversion unit 330 can be respectively connected to the communication conversion unit 320 and the low-voltage side communication module 400. The first level conversion unit 330 can be used to perform level conversion on the signal output by the communication conversion unit 320 or the signal output by the low-voltage side communication module 400. Different devices or circuit modules may operate at different voltage levels. In the embodiment of the present application, there is a voltage incompatibility between the communication conversion unit 320 and the low-voltage side communication module 400. The first level conversion unit 330 is used to adjust the voltage level of the signal to ensure that data can be correctly transmitted from the communication conversion unit 320 to the low-voltage side communication module 400, or from the low-voltage side communication module 400 to the communication conversion unit 320.

[0030] In one embodiment, the communication conversion unit 320 can include two connected RS485 chips. In a specific implementation manner, two MAX485 chips are used to achieve the conversion between TTL / CMOS logic levels and RS485 bus differential signals. The MAX485 chip supports the half-duplex communication mode, that is, only the send or receive operation can be performed at the same time. In this embodiment, the MAX485 chip connected to the low-voltage side main control unit 310 is defined as MAX485_1, and the MAX485 chip connected to the first level conversion unit 330 is defined as MAX485_2. The level of communication between MAX485_1 and the low-voltage side main control unit 310 is 0 / 1, and the signal AB between the two MAX485 chips is a differential signal. The purpose of setting two MAX485 chips is to improve the anti-interference ability of the system.

[0031] In one embodiment, the two RS485 chips are connected by twisted pair. The two RS485 chips use the twisted pair to transmit the pair of differential signals of signal AB, which can improve the anti-interference ability of the signal.

[0032] The main MCU communicates with the slave MCU through two MAX485 chips, and the communication transmission between the main MCU and the slave MCU is realized based on the Modbus RTU protocol of RS485. Among them, both MAX485 chips are located at the low-voltage end, and the cable connecting the two MAX485 chips is a twisted pair. The reception, transmission, and enabling of MAX485_2 are realized through optoelectronic conversion and reach the slave MCU. Thus, the RS485 and optical fiber bridging communication is achieved. The high-voltage isolation control system provided by this application has the ability of high-voltage isolation, and the withstand voltage level exceeds -200 kV. The use of optical fiber 10 transmission realizes full electrical isolation, and the use of dual RS485 chips suppresses common-mode noise. By reusing the Modbus RTU protocol based on RS485, complex protocol development can be avoided, the system complexity and cost can be reduced, and the system reliability can be improved.

[0033] Figure 3 This is a schematic structural diagram of the high-voltage side control module in one embodiment of this application. In one embodiment, the high-voltage side control module 100 may include a high-voltage side main control unit 110 and a second level conversion unit 120.

[0034] The high-voltage side main control unit 110 can be used to output an enabling signal or a high-voltage side signal, and the high-voltage side main control unit 110 can also be used to receive a low-voltage side signal. In this embodiment, the high-voltage side main control unit 110 can be a slave MCU. The main MCU can be used to initiate and control signals. The slave MCU is responsible for receiving the control instructions sent by the main MCU through optoelectronic conversion and the RS485 communication link. For example, in the application scenario of the transmission electron microscope field emission electron gun power supply system, when the main MCU issues instructions to adjust the power output or query the status, the slave MCU will perform corresponding operations after receiving these instructions. The slave MCU monitors and collects various operating parameters on the high-voltage side (such as voltage, current, vacuum degree, temperature, etc.), and can also process and feedback these data to the main MCU. This helps the main MCU to perform real-time monitoring and decision-making to ensure the stable operation of the entire system.

[0035] The second level conversion unit 120 can be respectively connected to the high-voltage side main control unit 110 and the high-voltage side communication module 200. The second level conversion unit 120 can be used to perform level conversion on the signal output by the high-voltage side main control unit 110 or the signal output by the high-voltage side communication module 200. In the embodiment of this application, there may be a situation where the voltages between the high-voltage side main control unit 110 and the high-voltage side communication module 200 are incompatible. The second level conversion unit 120 is used to adjust the voltage level of the signal to ensure that data can be correctly transmitted from the high-voltage side main control unit 110 to the high-voltage side communication module 200, or from the high-voltage side communication module 200 to the second level conversion unit 120.

[0036] Figure 4Schematic diagram of the circuit connection between the low-voltage side communication module and the high-voltage side communication module in one embodiment of the present application. In one embodiment, the circuit structures of the first transmission unit 410 in the low-voltage side communication module 400, the second transmission unit 220 and the third transmission unit 230 in the high-voltage side communication module 200 are the same. In this embodiment, the circuit structure of the first transmission unit 410 is taken as an example for illustration. The first transmission unit 410 may include an optical fiber transmitter U1, a first capacitor C1, a first diode D1, a second diode D2, a third diode D3, a first resistor R1 and a second resistor R2.

[0037] The first pin 1 of the optical fiber transmitter U1 can be connected to the first voltage source and the first end of the first capacitor C1. In this embodiment, the voltage provided by the first voltage source is +5V. The second end of the first capacitor C1 is connected to the reference ground. The first pin of the optical fiber transmitter U1 can also be respectively connected to the negative electrodes of the first diode D1 and the second diode D2. The second pin of the optical fiber transmitter U1 can be respectively connected to the positive electrode of the second diode D2 and the first end of the second resistor R2. The second end of the second resistor R2 can be respectively connected to the positive electrode of the first diode D1, the negative electrode of the third diode D3 and the first end of the first resistor R1. The second end of the first resistor R1 can be connected to the low-voltage side control module 300 or the high-voltage side control module 100. Specifically, the second end of the first resistor R1 can be connected to the first level conversion unit 330 or the second level conversion unit 120. The positive electrode of the third diode D3 is connected to the reference ground.

[0038] Among them, the optical fiber transmitter U1 can be an infrared optical fiber transmitting device with a wavelength of 600nm to 1310nm and a maximum transmission rate of 5Mbps. The first diode D1 and the second diode D2 can be transient voltage suppression diodes. The first diode D1 and the second diode D2 can be used to clamp the voltage at the input pin of the optical fiber transmitter U1, that is, the first pin 1 of the optical fiber transmitter U1. The third diode D3 can be a Schottky diode. The third diode D3 can be used to accelerate the signal edge.

[0039] In one embodiment, the circuit structures of the first receiving unit 210 in the high-voltage side communication module 200, the second receiving unit 420 and the third receiving unit 430 in the low-voltage side communication module 400 are the same. In this embodiment, the circuit structure of the first receiving unit 210 is taken as an example for illustration. The first receiving unit 210 may include an optical fiber receiver U2, a second capacitor C2, a fourth diode D4, a fifth diode D5, a third resistor R3 and a fourth resistor R4.

[0040] The first pin of the fiber optic receiver U2 and the third pin of the fiber optic receiver U2 can both be connected to the first end of the third resistor R3. The second end of the third resistor R3 can be respectively connected to the positive electrode of the fourth diode D4, the negative electrode of the fifth diode D5, and the first end of the fourth resistor R4. The second end of the fourth resistor R4 can be connected to the low-voltage side control module 300 or the high-voltage side control module 100. Specifically, the second end of the fourth resistor R4 can be connected to the first level conversion unit 330 or the second level conversion unit 120. The second pin of the fiber optic receiver U2 and the positive electrode of the fifth diode D5 can both be connected to the reference ground. The fourth pin of the fiber optic receiver U2 can be respectively connected to the first voltage source, the negative electrode of the fourth diode D4, and the first end of the second capacitor C2. The second end of the second capacitor C2 is connected to the reference ground.

[0041] Among them, the fiber optic receiver U2 can be an infrared fiber optic receiving device with a wavelength of 600 nm to 1310 nm and a maximum transmission rate of 5 Mbps. The fourth diode D4 can be a transient voltage suppression diode, and the fourth diode D4 can be used to clamp the voltage at the input pin of the fiber optic receiver U2, that is, the second pin of the fiber optic receiver U2. The fifth diode D5 can be a Schottky diode, and the fifth diode D5 can be used to accelerate the signal edge.

[0042] Figure 5 This is a schematic diagram of the circuit structure of the first level conversion unit in one embodiment of the present application. In one embodiment, the circuit structures of the first level conversion unit 330 and the second level conversion unit 120 are the same. The first level conversion unit 330 can include a level conversion chip U3, a third capacitor C3, a fourth capacitor C4, a fifth resistor R5, and a sixth resistor R6.

[0043] The input side of the level conversion chip U3 supports 3.3V logic level, and the output side supports 5V logic level. The level conversion chip U3 can be used to implement signal level conversion between 3.3V logic level and 5V logic level.

[0044] The power supply voltage pin on the input side of the level conversion chip U3 is connected to the first voltage source, and the power supply voltage pin on the output side of the level conversion chip U3 is connected to the second voltage source, or the power supply voltage pin on the input side of the level conversion chip U3 is connected to the second voltage source, and the power supply voltage pin on the output side of the level conversion chip U3 is connected to the first voltage source.

[0045] The input-side power supply voltage pin of the level conversion chip U3 can also be connected to the first end of a third capacitor C3, and the second end of the third capacitor C3 is connected to the reference ground. The output-side power supply voltage pin of the level conversion chip U3 can also be connected to the first end of a fourth capacitor C4. The second end of the fourth capacitor C4 and the ground pin of the level conversion chip U3 can both be connected to the reference ground. The output enable pin of the level conversion chip U3 can be respectively connected to the first end of a fifth resistor R5 and the first end of a sixth resistor R6. The second end of the fifth resistor R5 can be connected to the reference ground, and the second end of the sixth resistor R6 can be connected to a first voltage source or a second voltage source. In this embodiment, the voltage provided by the second voltage source is +3.3V.

[0046] In one of the embodiments, the reference ground of the high-voltage side control module 100 and the high-voltage side communication module 200 is -200 kV, and the reference ground of the low-voltage side control module 300 and the low-voltage side communication module 400 is the earth ground.

[0047] Figure 6 This is a schematic circuit diagram of the high-voltage isolation control system in one embodiment of the present application. In this embodiment, taking Figure 6 the shown high-voltage isolation control system as an example, the two-way communication working process of the high-voltage isolation control system is described. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. The high-voltage side main control unit 110 can also be connected to peripherals 1, 2,..., n, and the high-voltage side main control unit 110 can also control peripherals 1, 2,..., n.

[0048] When the low-voltage side sends a signal to the high-voltage side, the low-voltage side main control unit 310 issues a low-voltage side signal TX. After passing through MAX485_1, MAX485_2, and the first level conversion unit 330 respectively, it reaches the input port of the first sending unit 410 at the low-voltage end. The fiber optic transmitter U1 converts the electrical signal TXD1 into an optical signal. The optical signal reaches the receiving port of the first receiving unit 210 at the high-voltage end, is converted into an electrical signal RXD1 by the fiber optic receiver U2, and after level conversion, finally reaches the high-voltage side main control unit 110.

[0049] When the high-voltage side sends a signal to the low-voltage side, an enable signal (485EN) must be sent first. The main control unit 110 on the high-voltage side sends the enable signal 485EN, which reaches the input port of the third sending unit 230 at the high-voltage end after passing through the second level conversion unit 120. The optical fiber transmitter U1 converts the electrical signal TXD3 into an optical signal. The optical signal reaches the receiving port of the third receiving unit 430 at the high-voltage end, is converted into an electrical signal RXD3 by the optical fiber receiver U2, and finally reaches the main control unit 310 on the low-voltage side after level conversion. Then, the main control unit 110 on the high-voltage side sends a high-voltage side signal, which reaches the input port of the second sending unit 220 at the high-voltage end after passing through the second level conversion unit 120. The optical fiber transmitter U1 converts the electrical signal TXD2 into an optical signal. The optical signal reaches the receiving port of the second receiving unit 420 at the high-voltage end, is converted into an electrical signal RXD2 by the optical fiber receiver U2, and finally reaches the main control unit 310 on the low-voltage side after level conversion.

[0050] In the above high-voltage isolation control system, the high-voltage side and the low-voltage side achieve fully isolated communication in three channels (receiving / sending / enabling) stably through three sets of signal transceiver units. The signals between the high-voltage side and the low-voltage side are transmitted bidirectionally through optical fibers to achieve full electrical isolation and avoid electromagnetic interference.

[0051] In the description of this specification, the description referring to terms such as "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0052] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0053] Each embodiment in this specification is described in a progressive manner. The same or similar parts between each embodiment can be referred to each other, and the key point of each embodiment is to illustrate the differences from other embodiments. The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A high voltage isolation control system, characterized in that: It includes a high-voltage side control module, a high-voltage side communication module, a low-voltage side control module and a low-voltage side communication module, wherein the high-voltage side control module is connected to the high-voltage side communication module, and the low-voltage side control module is connected to the low-voltage side communication module. The low-voltage side communication module includes a first sending unit, a second receiving unit and a third receiving unit, and the high-voltage side communication module includes a first receiving unit, a second sending unit and a third sending unit, the first sending unit and the first receiving unit are connected to each other through an optical fiber, the second sending unit and the second receiving unit are connected to each other through the optical fiber, and the third sending unit and the third receiving unit are connected to each other through the optical fiber. The low-voltage side control module transmits the low-voltage side signal to the first receiving unit through the first sending unit, and the first receiving unit transmits the low-voltage side signal to the high-voltage side control module. The high-voltage side control module transmits the enable signal to the third receiving unit through the third sending unit, and the third receiving unit transmits the enable signal to the low-voltage side control module. The high-voltage side control module transmits the high-voltage side signal to the second receiving unit through the second sending unit, and the second receiving unit transmits the high-voltage side signal to the low-voltage side control module.

2. The high voltage isolation control system according to claim 1, characterized in that: An RS485 physical interface is used between the high-voltage side communication module and the low-voltage side communication module, and an application layer protocol between the high-voltage side communication module and the low-voltage side communication module is Modbus RTU.

3. The high voltage isolation control system according to claim 2, characterized in that: The low-voltage side control module comprises: A low-voltage side main control unit, used to output the low-voltage side signal, and also used to receive the enable signal or the high-voltage side signal; A communication conversion unit, connected to the low-voltage side main control unit, for converting the low-voltage side signal into a signal suitable for RS485 transmission; The first level conversion unit is connected to the communication conversion unit and the low-voltage side communication module respectively, and is used to perform level conversion on the signal output by the communication conversion unit or the signal output by the low-voltage side communication module.

4. The high voltage isolation control system according to claim 3, characterized in that: The communication conversion unit includes two connected RS485 chips.

5. The high voltage isolation control system according to claim 4, characterized in that: The two RS485 chips are connected via a twisted pair cable.

6. The high voltage isolation control system according to claim 1, characterized in that: The high-voltage side control module comprises: A high-voltage side main control unit, used to output the enable signal or the high-voltage side signal, and also used to receive a low-voltage side signal; The second level conversion unit is connected to the high-voltage side main control unit and the high-voltage side communication module respectively, and is used for level conversion of the signal output by the high-voltage side main control unit or the signal output by the high-voltage side communication module.

7. The high voltage isolation control system according to claim 1, characterized in that: The first sending unit, the second sending unit and the third sending unit have the same circuit structure. The first sending unit includes an optical fiber transmitter, a first capacitor, a first diode, a second diode, a third diode, a first resistor and a second resistor. The optical fiber transmitter is an infrared optical fiber transmitting device with a wavelength of 600nm~1310nm and a maximum transmission rate of 5Mbps; the first diode and the second diode are transient voltage suppression diodes, which are used to clamp the voltage at the input pin of the optical fiber transmitter; the third diode is a Schottky diode, which is used to accelerate the signal edge; The first pin of the optical fiber transmitter is connected to the first voltage source and the first end of the first capacitor, the second end of the first capacitor is connected to the reference ground, the first pin of the optical fiber transmitter is also connected to the cathode of the first diode and the cathode of the second diode, respectively, the second pin of the optical fiber transmitter is connected to the anode of the second diode and the first end of the second resistor, the second end of the second resistor is connected to the anode of the first diode, the cathode of the third diode and the first end of the first resistor, respectively, the second end of the first resistor is connected to the low-voltage side control module or the high-voltage side control module, and the anode of the third diode is connected to the reference ground.

8. The high voltage isolation control system according to claim 1, characterized in that: The first receiving unit, the second receiving unit and the third receiving unit have the same circuit structure. The first receiving unit includes an optical fiber receiver, a second capacitor, a fourth diode, a fifth diode, a third resistor and a fourth resistor. Wherein, the optical fiber receiver is an infrared optical fiber receiving device with a wavelength of 600nm~1310nm and a maximum transmission rate of 5Mbps; the fourth diode is a transient voltage suppression diode, which is used to clamp the voltage at the input pin of the optical fiber receiver; the fifth diode is a Schottky diode, which is used to accelerate the signal edge; The first pin of the optical fiber receiver and the fourth pin of the optical fiber receiver are both connected to the first end of the third resistor, the second end of the third resistor is respectively connected to the anode of the fourth diode, the cathode of the fifth diode and the first end of the fourth resistor, the second end of the fourth resistor is connected to the low-voltage side control module or the high-voltage side control module, the second pin of the optical fiber receiver and the anode of the fifth diode are both connected to the reference ground, the third pin of the optical fiber receiver is respectively connected to the first voltage source, the cathode of the fourth diode and the first end of the second capacitor, and the second end of the second capacitor is connected to the reference ground.

9. The high voltage isolation control system according to claim 3 or 6, characterized in that: The first level conversion unit has the same circuit structure as the second level conversion unit. The first level conversion unit includes a level conversion chip, a third capacitor, a fourth capacitor, a fifth resistor and a sixth resistor. The input side power supply voltage pin of the level conversion chip is connected to the first voltage source, and the output side power supply voltage pin of the level conversion chip is connected to the second voltage source, or the input side power supply voltage pin of the level conversion chip is connected to the second voltage source, and the output side power supply voltage pin of the level conversion chip is connected to the first voltage source, The input side power supply voltage pin of the level conversion chip is connected to the first end of the third capacitor, the second end of the third capacitor is connected to the reference ground, the output side power supply voltage pin of the level conversion chip is connected to the first end of the fourth capacitor, the second end of the fourth capacitor and the ground pin of the level conversion chip are both connected to the reference ground, the output enable pin of the level conversion chip is respectively connected to the first end of the fifth resistor and the first end of the sixth resistor, the second end of the fifth resistor is connected to the reference ground, and the second end of the sixth resistor is connected to the first voltage source or the second voltage source.

10. The high voltage isolation control system according to claim 9, characterized in that: The reference ground of the high-voltage side control module and the high-voltage side communication module is -200 kV, and the reference ground of the low-voltage side control module and the low-voltage side communication module is the earth.

Images