A proportional solenoid control system

Abstract

The application discloses a proportional electromagnet control system, comprising an electromagnet current detection module, which is used for monitoring the output current of a proportional electromagnet, converting the output current into voltage one in a required voltage range; an input control signal detection module, which is used for receiving a control signal, converting the control signal into voltage two in a required voltage range; an MCU module, which is used for obtaining a PWM signal according to the voltage one and the voltage two; and a MOSFET output module, which is used for driving the proportional electromagnet according to the PWM signal. By adding the proportional electromagnet current detection module and the current closed-loop control method, the influence of the environment on the output electromagnetic force of the proportional electromagnet is reduced, the output flow stability and precision of the proportional servo valve are improved, the manufacturing and testing costs are reduced, and the large-scale production is facilitated.

Description

Technical Field

[0001] This invention relates to the field of proportional servo valve control technology, and more specifically to a proportional electromagnet control system. Background Technology

[0002] A proportional servo valve generally consists of two main parts: a pilot-operated proportional servo control valve and a main valve. The pilot-operated proportional servo control valve includes a proportional solenoid, a servo control system, and a pilot valve core. The proportional solenoid consists of a coil and an armature. The electrical parameters of the coil change with temperature, causing the output electromagnetic force of the solenoid to be significantly affected by the environment during operation. This fluctuation in the output electromagnetic force leads to unstable output pressure in the pilot-operated proportional servo control valve, and fluctuations in the output flow of the main valve due to environmental influences.

[0003] Because there is no external flow meter signal input, the electrical parameters of the electromagnet coil are greatly affected by the environment. Currently, proportional servo control valves mainly adopt open-loop control mode. Proportional servo control valves cannot achieve closed-loop control of output flow independently, which leads to a significant increase in the manufacturing and testing costs of proportional servo valves, hindering mass production. Therefore, it is of great significance to reduce the fluctuation of the electromagnetic force output by the proportional electromagnet and improve the stability of the output flow of the proportional servo valve.

[0004] At the same time, it should be noted that the information disclosed in this background section is intended only to enhance the understanding of the overall background of the present invention, and should not be regarded as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a proportional electromagnet control system to solve the problems mentioned above. By adding a proportional electromagnet current detection module and a current closed-loop control method, the influence of the environment on the output electromagnetic force of the proportional electromagnet is reduced, the stability and accuracy of the output flow of the proportional servo valve are improved, the processing, manufacturing and testing costs are reduced, and it is convenient for mass production.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A proportional electromagnet control system includes,

[0008] The system includes an electromagnet current detection module and an input control signal detection module. The outputs of both modules are connected to the input of an MCU module. The output of the MCU module is connected to the input of a MOSFET output module. The output of the MOSFET output module is connected to a proportional electromagnet. The output of the proportional electromagnet is connected to the input of the electromagnet current detection module.

[0009] An electromagnet current detection module is used to monitor the output current of a proportional electromagnet and convert the output current into a voltage within the required voltage range.

[0010] An input control signal detection module is used to receive control signals and convert the control signals into a voltage within the required voltage range.

[0011] The MCU module is used to obtain a PWM signal based on the first voltage and the second voltage.

[0012] A MOSFET output module is used to drive the proportional electromagnet according to the PWM signal.

[0013] To further optimize the above technical solution, the required voltage range is the operating voltage of the MCU module.

[0014] To further optimize the above technical solution, the electromagnet current detection module converts the output current of the proportional electromagnet into voltage through a Hall current sensor, and obtains the voltage through a resistor divider.

[0015] To further optimize the above technical solution, the input control signal detection module converts the control signal through a DC / DC unit and then obtains the voltage second through a resistor voltage divider.

[0016] To further optimize the above technical solution, the MOSFET output module isolates the PWM signal and converts it into a MOSFET drive control signal through an isolation unit, thereby driving the proportional electromagnet through the MOSFET.

[0017] To further optimize the above technical solution, a power supply module is also included, which is divided into a first-level circuit, a second-level circuit, and a third-level circuit.

[0018] The first-stage circuit is used to convert the power supply voltage to power the MOSFET output module.

[0019] The second-stage circuit is used to convert the power supply voltage to power the third-stage circuit and the input control signal detection module.

[0020] The third-stage circuit is used to further convert the voltage converted by the second-stage circuit to power the MCU control module.

[0021] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a proportional electromagnet control system. By adding an electromagnet current detection module and a current closed-loop control method, the influence of the environment on the output electromagnetic force of the proportional electromagnet is reduced, the stability of the output flow of the proportional servo valve is improved, and a modular design scheme is adopted for the control of the proportional servo valve. At the same time, it also brings convenience to future product expansion and shortens the design cycle. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is an electrical schematic diagram of the proportional servo valve control system in this invention.

[0024] Figure 2 This is a circuit diagram of the electromagnet current detection module in this invention;

[0025] Figure 3 This is a circuit schematic diagram of the input control signal detection module in this invention;

[0026] Figure 4 This is a circuit schematic diagram of the MOSFET output module in this invention;

[0027] Figure 5 This is a schematic diagram of the first-stage circuit of the power module in this invention;

[0028] Figure 6 This is a schematic diagram of the second-stage circuit of the power module in this invention;

[0029] Figure 7 This is the schematic diagram of the third-stage circuit of the power module in this invention;

[0030] Figure 8 This is a schematic diagram of the overall circuit of the proportional electromagnet control system in this invention;

[0031] Figure 9 This is a flowchart of the control logic of the control system of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] This invention discloses a proportional electromagnet control system, such as... Figure 1 As shown, it includes an electromagnet current detection module 2 and an input control signal detection module 6. The output terminals of both are connected to the input terminal of the MCU module 3, and the output terminal of the MCU module 3 is connected to the proportional electromagnet 5 through the MOSFET output module 4.

[0034] The input terminal of the electromagnet current detection module 2 is connected to the output terminal of the proportional electromagnet 5, and the input terminal of the input control signal detection module 6 receives the input control signal.

[0035] Specifically,

[0036] Electromagnet current detection module 2 is used to monitor the output current of the proportional electromagnet and convert the output current into a voltage within the required voltage range.

[0037] The input control signal detection module 6 is used to receive control signals and convert the control signals into voltage II within the required voltage range;

[0038] In this embodiment, the required voltage range is the operating voltage of the MCU module 3.

[0039] MCU module 3 is used to obtain a PWM signal based on voltage one and voltage two;

[0040] MOSFET output module 4 is used to drive the proportional electromagnet 5 according to the PWM signal.

[0041] This invention reduces the environmental influence on the output electromagnetic force of the proportional electromagnet by adding an electromagnet current detection module 2 and a current closed-loop control method, thereby improving the stability and accuracy of the output flow of the proportional servo valve.

[0042] To clearly illustrate the implementation process of this invention, the specific circuit structure of each module is described below with reference to the accompanying drawings.

[0043] Example 1

[0044] First, the electromagnet current detection module 2 converts the output current of the proportional electromagnet into a voltage using a Hall current sensor, and then obtains the voltage through a resistor divider. The specific circuit structure is as follows: Figure 2 As shown,

[0045] The output terminal of the proportional electromagnet 5 is connected to pin IP+ of the Hall current sensor U5. The Hall current sensor U5 converts the output current IQA of the proportional electromagnet into a voltage within the range of 0-5V. The converted voltage is output through pin Vlout.

[0046] Meanwhile, pin Vlout is grounded through resistors R6 and R7, and capacitor C25 is connected between resistors R6 and R7. Resistors R6 and R7 are used to divide the voltage output by Hall current sensor U5 to obtain signal AIN6 in the range of 0-3.3V. Capacitor C25 is used to filter signal AIN6 to obtain a stable signal, which is then output to MCU control module 3 through point A.

[0047] Furthermore, the IP pin of the Hall current sensor U5 is connected to the analog ground, the Vref pin is connected to the isolation ground through capacitor C24, and the VCC pin is connected to the isolation ground through capacitor C22.

[0048] For the input control signal detection module 6, it is used to convert the control signal through a DC / DC unit and then obtain the voltage two through a resistor voltage divider. Its structure is as follows: Figure 3 As shown,

[0049] In the DC / DC unit, pins SIN+ and SIN- are used as input terminals to receive input control signals. The range of the control signals is 0-±10V. The DC / DC unit converts the input signals into signals within the range of 0-5V and outputs them through pins VO+ and VO-.

[0050] Among them, resistors R2 and R3 are connected in parallel between pins VO+ and VO-, and capacitor C25 is connected between resistors R2 and R3. Resistors R2 and R3 are used to divide the converted signal to obtain signal AIN0 in the range of 0-3.3V. Signal AIN0 is filtered and regulated by capacitor C11 and then output to MCU module 3 through point B.

[0051] In the DC / DC unit, PWR+ and PWR- are power supply pins.

[0052] After receiving the control signal, the MCU module performs curve lookup and interpolation calculations based on the proportional electromagnet input voltage and output target current curve stored in the MCU module to obtain the target current of the proportional electromagnet. According to the output voltage and input current ratio correspondence in the Hall current sensor chip datasheet, the voltage acquired by the Hall current sensor can be used to calculate the actual current of the proportional electromagnet. The MCU module performs PID calculations based on the target current AIN0 and the real-time detected actual current AIN1 of the proportional electromagnet to obtain the target PWM output duty cycle. The timer in MCU module 3 outputs the corresponding PWM signal according to the target output duty cycle.

[0053] The MOSFET output module is used to convert the PWM signal into a MOSFET drive control signal through isolation unit, and then drive the proportional electromagnet through the MOSFET. The specific implementation is as follows: Figure 4 As shown;

[0054] The PWM signal TIM1CH1N output by MCU module 3 is input to the input terminal of isolation module E1 through resistor R12, thereby converting it into a MOSFET drive control signal. This drive signal is connected to the gate of the MOSFET through resistor R14, and controls the proportional electromagnet through its drain (point C). One end of the proportional electromagnet is connected to 2L+, and the other end is connected to outA. When V9 is on, the proportional electromagnet is grounded through outA, and the proportional electromagnet outputs force. When V9 is off, the level of outA is the same as that of 2L+, and the proportional electromagnet has no output.

[0055] The isolation module has a power supply pin for connecting to a power supply to provide a +15V voltage to the isolation module. The source of the MOSFET is connected to the gate of the MOSFET in reverse through the Zener diode V7, and the drain is connected to the +24V power supply through V9.

[0056] The above modules have simple circuit structures and can be connected together to form a highly integrated proportional electromagnet control module or device. They can individually realize closed-loop control of output flow, and have low cost, making them easy to mass-produce.

[0057] Example 2

[0058] Based on the scheme disclosed in Embodiment 1, Embodiment 2 of the present invention further includes a power supply module for supplying power to the other modules. The power supply module can be divided into a first-level circuit, a second-level circuit, and a third-level circuit.

[0059] The first-stage circuit converts the power supply voltage to power the MOSFET output module. The DC / DC unit U1 converts the input voltage to the 15V required by the MOSFET output module. The circuit structure is as follows: Figure 5 As shown,

[0060] The input voltage passes through fuse F1, diode V1, and inductor L2 in sequence to enter the input terminal of the DC / DC unit. The inductor L2 is grounded through capacitor C4, and the output terminal of the DC / DC unit is grounded through capacitor C3.

[0061] The second-stage circuit converts the power supply voltage to power the third-stage circuit and the input control signal detection module. The circuit structure is as follows: Figure 6 As shown,

[0062] After passing through fuse F1 and diode V1, the input voltage enters the DC / DC unit U2 through inductor L3. The DC / DC unit U2 converts the input voltage into the voltage required by the electromagnet current detection module and outputs it through pin Vo.

[0063] Among them, the two ends of inductor L3 are grounded through capacitors C5 and C6 respectively, and capacitor C7 is connected in parallel between pin Vo and pin 0V of DC / DC unit U2, capacitor C8 is connected in parallel between pin 0V and pin CS, and pin 0V is connected to GND pin through capacitor C10.

[0064] The third-stage circuit further converts the voltage obtained from the second-stage circuit to power the MCU control module. Its circuit structure is as follows: Figure 7 As shown,

[0065] The IN pin of DC / DC unit U3 is connected to the Vo pin of DC / DC unit U2. It receives the voltage converted by the second-stage circuit, further converts it into the voltage required by the MCU module, and finally outputs it through the OUT pin.

[0066] Meanwhile, the GND pin of DC / DC unit U3 is connected to the 0V pin of DC / DC unit U2 and is grounded at the same time. A capacitor C9 is connected in parallel between its OUT pin and GND pin, as well as a resistor R1 and a diode V2 connected in parallel, wherein the resistor R1 and the diode V2 are connected in series.

[0067] The overall circuit after integrating the above modules is as follows: Figure 8 As shown, the integrated circuit of this invention can independently achieve closed-loop control of the proportional electromagnet. Furthermore, this integrated circuit can be fabricated as a circuit board, effectively reducing costs and facilitating mass production.

[0068] In use, its principle control process is as follows, such as Figure 9 As shown:

[0069] (1) After the control system is powered on, the MCU module performs program initialization settings for the timer, current detection module, input control signal detection module and closed-loop control module. After initialization, it enters closed-loop control.

[0070] (2) When the input control signal changes, the input control signal is analyzed to obtain the target control value; otherwise, the current closed-loop control continues.

[0071] The analysis process is as follows: based on the changed input control signal, a table lookup and interpolation calculation are performed to obtain the target current of the proportional electromagnet.

[0072] (3) The MCU module performs PID calculations based on the target current of the proportional electromagnet and the actual current of the proportional electromagnet detected in real time to obtain the target PWM output duty cycle. The MCU module timer outputs the corresponding PWM signal based on the target output duty cycle.

[0073] (4) The proportional electromagnet is controlled by the MOSFET output module according to the output PWM signal.

[0074] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0075] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A proportional electromagnet control system, characterized in that, It includes an electromagnet current detection module and an input control signal detection module. The output terminals of the electromagnet current detection module and the input control signal detection module are both connected to the input terminal of the MCU module. The output terminal of the MCU module is connected to the input terminal of the MOSFET output module. The output terminal of the MOSFET output module is connected to a proportional electromagnet. The output terminal of the proportional electromagnet is connected to the input terminal of the electromagnet current detection module. It also includes a power module, which is divided into a first-level circuit, a second-level circuit, and a third-level circuit. The first-stage circuit is used to convert the power supply voltage to power the MOSFET output module. The second-stage circuit is used to convert the power supply voltage to power the third-stage circuit and the input control signal detection module. The third-stage circuit is used to further convert the voltage converted by the second-stage circuit to power the MCU module. in, The electromagnet current detection module is used to monitor the output current of the proportional electromagnet and convert the output current into a voltage within the required voltage range; the electromagnet current detection module converts the output current of the proportional electromagnet into voltage through a Hall current sensor, and obtains the voltage through a resistor voltage divider. The input control signal detection module is used to receive control signals and convert the control signals into a voltage II within the required voltage range; after the control signals are converted by the DC / DC unit, the voltage II is obtained by resistor voltage division; The MCU module is used to obtain a PWM signal based on voltage one and voltage two; to perform curve lookup and interpolation calculations based on the proportional electromagnet input voltage and output target current curve stored in the MCU module to obtain the target current of the proportional electromagnet; to calculate the actual current of the proportional electromagnet based on the output voltage and input current ratio correspondence in the Hall current sensor chip manual, and the voltage one collected by the Hall current sensor; to perform PID calculations based on the target current AIN0 and the real-time detected actual current AIN1 of the proportional electromagnet to obtain the target output duty cycle of the PWM; and to output the corresponding PWM signal based on the target output duty cycle of the timer in the MCU module. The MOSFET output module is used to drive the proportional electromagnet according to the PWM signal; the MOSFET output module converts the PWM signal into a MOSFET drive control signal through an isolation unit, and drives the proportional electromagnet through the MOSFET; the required voltage range is the operating voltage of the MCU module.

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