A high-pressure pump constant pressure and constant speed dual-mode control circuit and method

Abstract

The present invention discloses a high-pressure pump constant pressure and constant speed dual-mode control circuit, including a main control module MCU, a power module, a solenoid valve drive module, a motor drive module, a bus voltage acquisition module and a three-phase full-bridge inverter circuit, wherein the three-phase full-bridge inverter circuit is electrically connected to the motor drive module and the main control module MCU respectively, and the power module, the solenoid valve drive module, and the bus voltage acquisition circuit are all electrically connected to the main control module MCU. Based on the stable control of motor speed, the present invention controls the number of channels of the solenoid valve according to the motor speed to ensure that the pressure in the pump is basically constant, thereby achieving the purpose of constant pressure; speeds up the control system response speed, realizes perfect closed-loop control, and can maintain a high-pressure pump with a constant pressure and constant speed dual-mode control circuit system under the conditions of adaptive load and adjusting motor speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-pressure pump circuit control, and in particular relates to a high-pressure pump constant pressure and constant speed dual-mode control circuit and method. Background Art

[0002] The working principle of a solenoid valve is as follows: the solenoid valve contains a sealed chamber with holes at different locations, each of which is connected to a different oil pipe. The valve is located in the center of the chamber, and on either side of the chamber are two electromagnets. Once the electromagnet coils are energized, the valve body is attracted to the direction of the energized electromagnets, and the valve body is attracted to the side with the energized electromagnet coils. The movement of the valve body is controlled to open or close different oil drain holes. Since the oil inlet hole is normally open, the movement of the valve body forces hydraulic oil into different oil drain pipes. The oil pressure then pushes the piston of the oil cylinder, which in turn pushes the piston rod, which in turn drives the mechanical device. Utilizing this principle, the current flowing through the electromagnet can be controlled to be on and off.

[0003] As a key component of electro-hydraulic automatic control systems, high-speed solenoid valves (HSVs) are widely used in the automotive and mechanical fields due to their ease of real-time control in a microprocessor environment, coupled with their fast response, simple structure, and low power consumption. In electro-hydraulic automatic control systems, they are ideal interface components for integrated mechatronic systems due to their compact structure, small size and light weight, fast response, high reliability, and excellent repeatability. Furthermore, their ability to directly receive digital signals from upstream and control the pressure or flow of downstream systems via PWM waves provides a technical means for digital control of the entire electro-hydraulic automatic control system.

[0004] However, the existing electro-hydraulic control system has slow response speed, insufficient closed-loop control, and the pressure and speed cannot be jointly adjusted. Summary of the Invention

[0005] In order to solve the problems of slow response speed and insufficient closed-loop control of the electro-hydraulic control system, the present invention is designed to provide a high-pressure pump with a constant pressure control and constant speed motor speed control that include coordinated operation of the solenoid valve, and a constant pressure and constant speed dual-mode control circuit system that can maintain stable pressure in the pump while adapting to the load and adjusting the motor speed.

[0006] A high-pressure pump constant pressure and constant speed dual-mode control circuit, including a main control module MCU, a power module, a solenoid valve drive module, a motor drive module, a bus voltage acquisition module and a three-phase full-bridge inverter circuit. The three-phase full-bridge inverter circuit is electrically connected to the motor drive module and the main control module MCU respectively, and the power module, the solenoid valve drive module, and the bus voltage acquisition circuit are all electrically connected to the main control module MCU;

[0007] The main control module MCU is used to coordinate the operation of the entire system and realize signal reception, processing and transmission;

[0008] The power supply module is used to provide power required by the circuit;

[0009] The solenoid valve drive module is used to receive instructions from the main control module MCU to realize dual voltage control of the solenoid valve;

[0010] The motor drive module is used to amplify the input weak current signal into a strong current signal for external equipment;

[0011] The bus voltage acquisition module is used to detect the voltage on the circuit bus in real time;

[0012] The three-phase full-bridge inverter circuit is used to control the rotation speed of the motor drive.

[0013] Furthermore, the power module includes an anti-reverse connection protection circuit, and the anti-reverse connection power supply circuit includes a MOS tube and a diode, and the conduction and disconnection of the circuit are controlled by the switching characteristics of the MOS tube.

[0014] Furthermore, the three-phase full-bridge inverter circuit includes an undervoltage and overcurrent protection circuit, which is connected to the OC pin of the main control module MCU. The undervoltage and overcurrent protection circuit controls the working state of the buzzer by comparing the voltage output high / low level of the positive and negative poles of the voltage comparator.

[0015] Furthermore, the solenoid valve driving module is connected to the AT and AB pins of the main control module MCU, and a time delay relay is set to change the duty cycle through pulse width modulation technology to reduce the current of the circuit.

[0016] Furthermore, the motor drive module is connected to the three-phase full-bridge inverter circuit through the MA, GAB, GAT, MB, GBB, GBT, MC, GCB, and GCT pins. The motor drive module of the circuit has independent low-voltage and high-voltage output channels, and can simultaneously control the switching of the MOS tubes of the three-phase full-bridge inverter circuit.

[0017] Furthermore, the main control module MCU is connected to a burning program circuit, which is connected to the PD0, PD1, PC14, and PC15 pins of the main control module MCU to burn the control algorithm code into the chip, so that the chip can control the high and low level logic input and output of each pin, thereby realizing various control functions.

[0018] Furthermore, the main control module MCU is connected to a key circuit, which is connected to the SW pin of the main control module MCU and includes a four-way key switch. The circuit control system can realize the start and stop and speed regulation functions of the motor through the key switch.

[0019] Furthermore, the main control module MCU is connected to a temperature protection circuit, and the temperature protection circuit is connected to an NTC pin of the main control module MCU. The temperature protection circuit is provided with an NTC thermistor. The corresponding relationship between temperature and resistance value is established by changing the resistance value of the NTC thermistor with temperature, thereby determining the current temperature value.

[0020] Furthermore, the main control module MCU is connected to a back electromotive force circuit, which is connected to the SA, SB, and SC pins of the main control module MCU. The motor commutation moment is obtained by back electromotive force detection to achieve motor speed control.

[0021] A method for a high-pressure pump constant pressure and constant speed dual-mode control circuit includes the following steps:

[0022] Step 1: Define variable parameters;

[0023] Step 1.1: Initialize resource configuration and define each pin;

[0024] Step 2: Start the solenoid valve;

[0025] Step 3: Start the motor;

[0026] Step 4: Joint control of the solenoid valve and motor;

[0027] Step 4.1: Read the motor rotor position signal and start the commutation program according to the size of the rotor position signal;

[0028] Step 4.1.1: When the rotor position signal exceeds the set value range, the stop button is activated, the PWM output is turned off, the motor stops, and the solenoid valve is closed;

[0029] Step 4.1.2: When the rotor position signal is less than the set value, start the commutation function, switch the rotor position signal, and re-read the rotor position signal;

[0030] Step 4.1.3: When the rotor position signal is within the set value range, press the accelerator or decelerator to adjust the motor's real-time speed and the set speed value. If the real-time speed is greater than the set speed value, increase the number of solenoid valve channels; if the real-time speed is less than the set speed value, reduce the number of solenoid valve channels.

[0031] Step 4.2: Collect the motor speed. If the real-time speed is greater than the set speed value, increase the number of solenoid valve channels; if the real-time speed is less than the set speed value, reduce the number of solenoid valve channels.

[0032] Step 4.3: Busbar high voltage acquisition RT segment AD acquisition, determine whether the temperature and voltage are abnormal. If the temperature and voltage are abnormal, turn off the PWM output, stop the motor, and close the solenoid valve; if the temperature and voltage are normal, continue the cycle acquisition;

[0033] Step 5: Use PWM's segmented modulation output to control the solenoid valve to start and stop quickly at a higher voltage, and maintain an open or closed state with lower energy consumption at a lower voltage. The control signal drives the MOS tube of the circuit to operate, thereby making the motor and solenoid valve operate in a closed loop.

[0034] Compared with the existing technology, the present invention has the following advantages: by designing a joint control program of the solenoid valve and the motor, on the basis of stable motor speed control, the solenoid valve controls the number of channels according to the motor speed to ensure that the pressure in the pump is basically constant, thereby achieving the purpose of constant pressure; it accelerates the response speed of the control system, realizes perfect closed-loop control, and is a high-pressure pump with a constant pressure and constant speed dual-mode control circuit system that can maintain stable pressure in the pump while adaptively adapting to the load and adjusting the motor speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the circuit diagram of the main control module MCU of the present invention;

[0036] Figure 2 This is a power supply circuit diagram of the present invention;

[0037] Figure 3 This is a circuit diagram of the anti-reverse connection power supply of the present invention;

[0038] Figure 4 This is a solenoid valve driving circuit diagram of the present invention;

[0039] Figure 5 This is a motor drive circuit diagram of the present invention;

[0040] Figure 6 This is a three-phase full-bridge inverter circuit diagram of the present invention;

[0041] Figure 7 This is the undervoltage and overcurrent protection circuit of the present invention;

[0042] Figure 8 This is a bus voltage detection circuit diagram of the present invention;

[0043] Figure 9 This is the temperature protection circuit of the present invention;

[0044] Figure 10 This is the key circuit of the present invention;

[0045] Figure 11 This is the circuit diagram of the power indicator light of the present invention;

[0046] Figure 12 This is the circuit diagram of the burning program of the present invention;

[0047] Figure 13 This is a back electromotive force detection circuit diagram of the present invention;

[0048] Figure 14It is the PID control diagram of the present invention;

[0049] Figure 15 It is a control flow chart of the present invention. Implementation Method

[0050] The present invention will be further described below with reference to the accompanying drawings.

[0051] The entire high-pressure pump system mainly consists of a micro plunger pump, sun and planetary gears, a brushless DC motor (BLDC), a three-position four-way solenoid valve, and a control PCB board. The motor and sun and planetary gears are connected through a shaft hole, and the micro plunger pump and sun and planetary gears are connected through a hexagon socket. This reduces the input speed, increases torque, and increases the stability of the transmission mechanism to achieve the purpose of ideal transmission effect.

[0052] like Figure 1-11 The high-pressure pump constant pressure and constant speed dual-mode control circuit shown includes a main control module MCU, a power module, a solenoid valve drive module, a motor drive module, a bus voltage acquisition module and a three-phase full-bridge inverter circuit. The three-phase full-bridge inverter circuit is electrically connected to the motor drive module and the main control module MCU respectively, and the power module, solenoid valve drive module, and bus voltage acquisition circuit are all electrically connected to the main control module MCU.

[0053] like Figure 2 and 3 As shown, the power module includes a reverse polarity protection circuit. This circuit primarily uses MOSFETs and diodes to prevent reverse polarity. The MOSFET reverse polarity protection circuit utilizes the switching characteristics of MOSFETs to control the on / off state of the circuit. Since MOSFETs can now achieve milliohm-level polarity, this solves the voltage drop and excessive power consumption issues associated with diode-based reverse polarity protection. If the polarity of the protected circuit's power supply is reversed, the protective field-effect transistor (FET) will open the circuit, preventing the current from burning out the FET components within the circuit and protecting the entire circuit. In this embodiment, a (HY1603) P-MOSFET is used to prevent system failures caused by reverse power connection. The output terminal is connected to the positive power supply, the input terminal is connected to the negative power supply, the 12V is connected to the positive terminal of the circuit board, and the GND is connected to the negative terminal of the circuit board. The P-MOSFET conduction condition is the voltage between the gate and source. When the power supply is connected in a positive direction, the gate is low, the MOSFET conducts, and the power supply operates normally. When the power supply is reversed, or the input and output are reversed, the gate is high, the MOSFET turns off, and the circuit does not operate.

[0054] In addition, the power supply circuit uses the principle of capacitor voltage reduction to achieve voltage reduction of the input voltage. It mainly consists of circuits such as a voltage reduction capacitor, current limiting, rectification filtering, and voltage stabilization and shunting. The principle is as follows: The amplitude / rms value of the voltage and current on the capacitor also follows Ohm's law. When the voltage amplitude and frequency applied to the capacitor are constant, a stable sinusoidal alternating current flows through. By connecting a suitable load in series with this capacitor, a reduced voltage source is obtained. After rectification and filtering, a stable output is achieved. In the power supply module, for the voltage reduction module, the 12V to 5V module uses a 78L05 chip, which is a commonly used three-terminal voltage regulator, stably outputting 5V voltage with an output current not exceeding 0.1A and having built-in overcurrent and overload protection circuits to supply power to some components; the 5V to 3.3V module uses an AMS1117-3.3 chip, which is a commonly used positive low-dropout voltage regulator, stabilizing the 5V voltage to 3.3V output and is commonly used to control the microcontroller with high-level signals.

[0055] As Figure 4 shown, the main function of the solenoid valve drive module is to drive the solenoid valve, receive instructions from the MCU main control chip to achieve dual-voltage control of the solenoid valve, and achieve high efficiency and energy saving of the solenoid valve. In the embodiment of this application, the solenoid valve drive module is centered around the IR2101S chip. The IR2101S integrated chip is a dual-channel, high-voltage, high-speed power driver. This chip can provide a driving voltage of up to 600V and has a large driving current; it has independent low-side and high-side output channels and can control the switching of two MOS transistors simultaneously. The internal block diagram and pin diagram of the IR2101S chip, where HIN corresponds to the high-side logic input, LIN corresponds to the low-side logic input, VDD corresponds to the logic power supply, VSS corresponds to the logic ground, VB corresponds to the high-side floating supply, HO corresponds to the high-side gate driver output, Vs corresponds to the return of the high-side floating supply, LO corresponds to the low-side gate driver output, and COM corresponds to the common ground terminal. The solenoid valve drive module includes a key circuit. The key circuit sets a delay relay, and changes the duty cycle through pulse width modulation technology to reduce the current in the circuit. The delay function (delay) called by the delay relay is used in the key program to avoid misjudgment by the microcontroller, effectively prevent IO jitter, and is also beneficial to improving the efficiency of the microcontroller. By using pulse width modulation technology, while achieving a fast response at the moment of starting the solenoid valve, during the stable stage of the solenoid valve, the duty cycle is reduced to lower the voltage across the electromagnet to reduce energy consumption. In the illustrated program, the set value of CCR2 is C, and the value of TIM3 during the solenoid valve opening stage is A, that is, the duty cycle is A / C; in the stable stage, the program autonomously controls and adjusts the value of TIM3 to B (B < A), that is, the duty cycle is reduced to B / C, reducing the pulse width to achieve the purpose of voltage reduction. It should be noted that at this time, the voltage is still greater than the minimum operating voltage of the solenoid valve, and the solenoid valve still operates normally.

[0056] As Figure 5As shown, the motor driver module amplifies weak input signals into strong enough signals for external devices. The motor driver module is connected to the three-phase full-bridge inverter circuit via the MA, GAB, GAT, MB, GBB, GBT, MC, GCB, and GCT pins. The motor driver module has independent low-voltage and high-voltage output channels, enabling simultaneous switching of the MOSFETs in the three-phase full-bridge inverter circuit. The motor driver module uses standard TTL logic level control signals and features two enable control pins that enable or disable device operation independent of input signals. It also has a logic power input that allows the internal logic circuitry to operate at low voltages. An external sense resistor provides feedback to the control circuitry. Like the solenoid valve driver module, the motor driver module uses the imported IRS2101S chip, which operates at 12V. The matching resistor is a 100R resistor. The MOSFETs act as coupling capacitors for current dissipation. The use of a 100R resistor necessitates an antiparallel diode to accelerate the MOSFET switching. Calculation shows that when the resistance is 10R, an anti-parallel diode is not required. However, too small a matching resistance may lead to other problems, such as excessive current, etc. Therefore, an anti-parallel diode is still used in this embodiment.

[0057] like Figure 6 and 7 As shown in the figure, the three-phase full-bridge inverter circuit includes an undervoltage and overcurrent protection circuit to prevent excessive current from burning out components, or to prevent undervoltage from causing abnormal circuit operation. The voltage of the inverter circuit is compared and analyzed with the reference voltage of the main control chip through a comparison operational amplifier, thereby realizing the circuit protection function. Figure 7 As shown, the OC port of the undervoltage and overcurrent protection circuit is connected to the main control module MCU. When the input voltage falls below the specified value, certain components on the circuit board, such as transistors and switching regulators, may malfunction, compromising circuit performance and endangering the power supply. The undervoltage and overcurrent protection circuit operates by comparing the voltages at the positive and negative terminals of the voltage comparator to output a high / low level, thereby controlling the operating state of the buzzer. If the voltage at the positive terminal of the voltage comparator is greater than the voltage at the negative terminal, the output is high, and the buzzer is deactivated. When the VCC voltage drops below the set value, the voltage at the positive terminal of the voltage comparator becomes less than the voltage at the negative terminal, resulting in a low output, a buzzer activation, and an alarm signal indicating insufficient power supply voltage.

[0058] like Figure 8As shown in the figure, to prevent operational errors that could cause damage to components due to excessive voltage across the terminals, or performance degradation due to insufficient voltage, a bus voltage detection circuit is implemented. This circuit monitors the voltage on the circuit bus in real time and, through the microcontroller, processes the signal and feeds it back to the drive circuit. The bus voltage detection circuit performs voltage detection. Resistors R4 and R6 are connected in series, and resistor R6 is connected in parallel with capacitor C6. X is R4, and Y is R6. The detected voltage is stepped down to Y * bus voltage / (X + Y). Since the microcontroller input voltage signal is 3.3V, the maximum detection voltage range is 0 to 3.3V.

[0059] like Figure 9 As shown in the figure, the increasing integration and miniaturization of components within microcontrollers have significantly increased their power density per unit volume. If the temperature resistance of these components is not improved, circuit performance will inevitably decline or even damage, leading to component failure. Therefore, the main control module (MCU) is connected to a temperature protection circuit, which is connected to the NTC pin of the main control module. This temperature protection circuit utilizes an NTC thermistor to protect components from failure or damage at high temperatures. This circuit uses the temperature-dependent resistance change of the thermistor to establish a relationship between temperature and resistance, thereby determining the current temperature. An NTC, also known as a negative temperature coefficient thermistor, decreases in resistance as temperature increases. At low temperatures, its resistance is very high, representing an open circuit. At high temperatures, exceeding the design temperature, its resistance is very low, representing a short circuit, effectively shutting down other circuits and protecting the circuit from damage.

[0060] like Figure 10As shown in the figure, the main control module MCU is connected to the key module. The key circuit is connected to the SW pin of the main control module MCU and includes four-way key switches. The circuit control system can achieve the functions of starting, stopping and speed regulation of the motor through the key switches. Through the key circuit on the PCB control board of the main control module MCU, the multi-channel operation of the solenoid valve can be controlled to meet the needs of the multi-functional parallel operation of the plunger pump. Multiple execution tools can be externally connected at the same time to complete the operations under complex working conditions. The solenoid valve control program uses pulse width modulation technology. By changing the duty cycle, a large starting current is given to the solenoid valve at the starting stage of the solenoid valve to ensure the quick response of the solenoid valve. After the response, in the holding state stage, the suction force required in the previous stage is not needed. In order to reduce the circuit energy consumption and extend the service life of the hardware, the design reduces the pulse duty cycle of the program circuit to reduce the current of the circuit, but still exceeds the adsorption current threshold of the solenoid valve, and the solenoid valve is still conducting and the energy consumption is reduced. The solenoid valve control program calls the delay function (delay) for the key program to avoid misjudgment of the single-chip microcomputer, effectively prevent IO jitter, and is also beneficial to the improvement of the efficiency of the single-chip microcomputer. Using pulse width modulation technology, while achieving a quick response at the moment of starting the solenoid valve, the duty cycle is reduced in the stable stage of the solenoid valve to reduce the voltage across the electromagnet to reduce the energy consumption. The CCR2 value set in the program is C, and the TIM3 value in the solenoid valve opening stage is A, that is, the duty cycle is A / C; in the stable stage, the program controls autonomously, adjusts the TIM3 value to B (B < A), that is, the duty cycle is reduced to B / C, reducing the pulse width to achieve the purpose of voltage reduction. It should be noted that at this time, the voltage is still greater than the minimum working voltage of the solenoid valve, and the solenoid valve still operates normally.

[0061] As Figure 11-13 shown, the main control module MCU is also connected to the power indicator circuit, the program burning circuit and the back electromotive force detection circuit. Among them, the main function of the power indicator circuit is to detect whether the power supply is powered on through the indicator light. The main function of the program burning circuit is to burn the algorithm code for realizing control into the chip, so that the chip can control the logical input and output of the high and low levels of each pin, thereby realizing various control functions, and is connected to the PD0, PD1, PC14, and PC15 pins of the main control module MCU. The back electromotive force circuit is connected to the SA, SB, and SC pins of the main control module MCU. It refers to the generation of electromotive force due to the tendency to resist the change of current. The brushless motor operating in the three-phase six-state 120° power-on mode is always powered on in two phases at any time, and the other phase winding is floating and not conducting. At this time, the terminal voltage of the non-conducting winding (from the winding end to the DC ground) or the phase voltage (from the winding end to the center point of the three-phase winding) reflects the induced electromotive force of this phase winding. By detecting the back electromotive force, the commutation moment of the motor can be obtained to realize the speed control of the motor.

[0062] As Figure 1As shown, in the embodiment of the present application, the main control module MCU selects STM32 single-chip microcomputer, which controls the three-way solenoid valve while controlling the starting voltage and the operating voltage through PWM pulse width modulation technology, and also accurately controls the motor speed, and adapts to the solenoid valve to achieve the control effect of constant voltage, constant speed and constant power system, while also having functions such as temperature protection, undervoltage detection, and overcurrent protection. Pulse width modulation technology is to modulate the width of a series of pulses through PWM signals, and the equivalent waveform digitally encodes the analog level signal, that is, to adjust the change of the signal and energy by adjusting the change of the duty cycle of the entire signal cycle. The motor control method of the present application adopts an incremental PID algorithm, such as Figure 14 As shown in the figure, after adjusting the proportional, integral, and differential parameters, the motor speed can be closed-loop controlled. The motor is initially under open-loop control, and a weighted transition is used to switch from open-loop to closed-loop control to reduce jitter during motor switching.

[0063] like Figure 15 The method of the high-pressure pump constant pressure and constant speed dual-mode control circuit shown includes the following steps:

[0064] Step 1: Define variable parameters, resource configuration initialization and definition of each pin;

[0065] Step 2: Start the solenoid valve;

[0066] Step 3: Start the motor;

[0067] Step 4: Joint control of the solenoid valve and motor;

[0068] Step 4.1: Read the motor rotor position signal and start the commutation program according to the size of the rotor position signal;

[0069] Step 4.1.1: When the rotor position signal exceeds the set value range, the stop button is activated, the PWM output is turned off, the motor stops, and the solenoid valve is closed;

[0070] Step 4.1.2: When the rotor position signal is less than the set value, start the commutation function, switch the rotor position signal, and re-read the rotor position signal; specifically, the rotor position signal can be a Hall signal value or a back electromotive force detection signal;

[0071] Step 4.1.3: When the rotor position signal is within the set value range, press the accelerator or decelerator to adjust the motor's real-time speed and the set speed value. If the real-time speed is greater than the set speed value, increase the number of solenoid valve channels; if the real-time speed is less than the set speed value, reduce the number of solenoid valve channels.

[0072] Step 4.2: Collect the motor speed. If the real-time speed is greater than the set speed value, increase the number of solenoid valve channels; if the real-time speed is less than the set speed value, reduce the number of solenoid valve channels.

[0073] Step 4.3: Busbar high voltage acquisition RT segment AD acquisition, determine whether the temperature and voltage are abnormal. If the temperature and voltage are abnormal, turn off the PWM output, stop the motor, and close the solenoid valve; if the temperature and voltage are normal, continue the cycle acquisition;

[0074] Step 5: Use PWM's segmented modulation output to control the solenoid valve to start and stop quickly at a higher voltage, and maintain an open (or closed) state with lower energy consumption at a lower voltage. The control signal drives the MOS tube of the circuit to operate, thereby making the motor and solenoid valve operate in a closed loop.

[0075] The principle of joint control of the solenoid valve and motor: The micro-plunger pump system is controlled to operate at constant pressure and speed. On the basis of stable motor speed control, the solenoid valve controls the number of channels according to the motor speed to ensure that the pressure in the pump is basically constant, achieving the purpose of constant pressure. The motor is designed with an initial speed. When the RUN button is pressed, the motor starts, and the solenoid valve opens a single channel at this time; as the motor speed increases, the pressure in the pump increases. When the motor speed is greater than the set value 1, the solenoid valve opens two channels to reduce the pressure and maintain the pressure in the pump stable; similarly, when the motor speed exceeds the set value 2, all three channels of the solenoid valve are opened; and when the motor slows down, the program will also autonomously control the solenoid valve channels to close. Of course, in order to deal with emergencies, when the system needs to stop working immediately, pressing the STOP button can simultaneously close all solenoid valve channels and the motor.

[0076] As you can understand, the delay function (delay) called in the keystroke program prevents MCU misjudgment, effectively reduces I / O jitter, and improves MCU efficiency. The design utilizes pulse-width modulation (PWM) technology. While ensuring a rapid response to the solenoid valve's activation, it also reduces the duty cycle during the solenoid's stabilization phase to lower the voltage across the electromagnet and reduce energy consumption. The program shown sets the CCR2 value to 200, and the TIM3 value to 160 during the solenoid's activation phase, resulting in an 80% duty cycle. During the stabilization phase, the program autonomously adjusts the TIM3 value to 150, reducing the duty cycle to 75%. This reduces the pulse width to achieve voltage reduction. However, it's important to note that at this point, the voltage is still greater than the solenoid's minimum operating voltage, allowing the valve to operate normally. Pressing the RUN button activates the motor, which reaches its initial speed, determined by the set initial duty cycle. After determining the initial speed, initial position correction is performed at the start of startup. Pre-positioning a fixed phase is performed, and the motor begins open-loop operation. To ensure stable switching from open-loop to closed-loop operation and prevent jitter caused by sudden switching and angle inconsistencies, a weighted stable switching method is used. At the beginning of the switching phase, the open-loop angle is given a higher weight, while at the end of the switching phase, the Hall effect angle is given a higher weight. This weighted transition method achieves stable switching.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-pressure pump constant pressure and constant speed dual-mode control circuit, characterized in that: It includes a main control module MCU, a power module, a solenoid valve drive module, a motor drive module, a bus voltage acquisition module and a three-phase full-bridge inverter circuit. The three-phase full-bridge inverter circuit is electrically connected to the motor drive module and the main control module MCU respectively, and the power module, the solenoid valve drive module and the bus voltage acquisition circuit are all electrically connected to the main control module MCU; The main control module MCU is used to coordinate the operation of the entire system and realize signal reception, processing and transmission; The power supply module is used to provide the power required by the circuit. The power supply module includes an anti-reverse connection protection circuit. The anti-reverse connection power supply circuit includes a MOS tube and a diode. The switching characteristics of the MOS tube are used to control the conduction and disconnection of the circuit. The solenoid valve drive module is used to receive instructions from the main control module MCU to realize dual voltage control of the solenoid valve; The motor drive module is used to amplify the input weak current signal into a strong current signal for external equipment; The bus voltage acquisition module is used to detect the voltage on the circuit bus in real time; The three-phase full-bridge inverter circuit is used to control the speed of the motor drive. The three-phase full-bridge inverter circuit includes an undervoltage and overcurrent protection circuit. The undervoltage and overcurrent protection circuit is connected to the OC pin of the main control module MCU. The undervoltage and overcurrent protection circuit outputs a high / low level by comparing the voltage of the positive and negative poles of the voltage comparator to control the working state of the buzzer; The control method of the dual-mode control circuit comprises the following steps: Step 1: Define variable parameters; Step 1.1: Initialize resource configuration and define each pin; Step 2: Start the solenoid valve; Step 3: Start the motor; Step 4: Joint control of the solenoid valve and motor; Step 4.1: Read the motor rotor position signal and start the commutation program according to the size of the rotor position signal; Step 4.1.1: When the rotor position signal exceeds the set value range, the stop button is activated, the PWM output is turned off, the motor stops, and the solenoid valve is closed; Step 4.1.2: When the rotor position signal is less than the set value, start the commutation function, switch the rotor position signal, and re-read the rotor position signal; Step 4.1.3: When the rotor position signal is within the set value range, press the accelerator or decelerator to adjust the motor's real-time speed and the set speed value. If the real-time speed is greater than the set speed value, increase the number of solenoid valve channels; if the real-time speed is less than the set speed value, reduce the number of solenoid valve channels. Step 4.2: Collect the motor speed. If the real-time speed is greater than the set speed value, increase the number of solenoid valve channels; if the real-time speed is less than the set speed value, reduce the number of solenoid valve channels. Step 4.3: Busbar high voltage acquisition RT segment AD acquisition, determine whether the temperature and voltage are abnormal. If the temperature and voltage are abnormal, turn off the PWM output, stop the motor, and close the solenoid valve; if the temperature and voltage are normal, continue the cycle acquisition; Step 5: Use PWM's segmented modulation output to control the solenoid valve to start and stop quickly at a higher voltage, and maintain an open or closed state with lower energy consumption at a lower voltage. The control signal drives the MOS tube of the circuit to operate, thereby making the motor and solenoid valve operate in a closed loop.

2. A high-pressure pump constant pressure and constant speed dual-mode control circuit according to claim 1, characterized in that: The solenoid valve drive module is connected to the AT and AB pins of the main control module MCU, and a time delay relay is set to reduce the current of the circuit by changing the duty cycle through pulse width modulation technology.

3. The high-pressure pump constant pressure and constant speed dual-mode control circuit according to claim 1, characterized in that: The motor drive module is connected to the three-phase full-bridge inverter circuit through the MA, GAB, GAT, MB, GBB, GBT, MC, GCB, and GCT pins. The motor drive module of the circuit has independent low-voltage and high-voltage output channels and can simultaneously control the switching of the MOS tubes of the three-phase full-bridge inverter circuit.

4. A high-pressure pump constant pressure and constant speed dual-mode control circuit according to claim 1, characterized in that: The main control module MCU is connected to a burning program circuit, which is connected to the PD0, PD1, PC14, and PC15 pins of the main control module MCU to burn the control algorithm code into the chip, so that the chip can control the high and low level logic input and output of each pin, thereby realizing various control functions.

5. A high-pressure pump constant pressure and constant speed dual-mode control circuit according to claim 4, characterized in that: The main control module MCU is connected to a key circuit, which is connected to the SW pin of the main control module MCU and includes a four-way key switch. The circuit control system can realize the start and stop and speed regulation functions of the motor through the key switch.

6. A high-pressure pump constant pressure and constant speed dual-mode control circuit according to claim 5, characterized in that: The main control module MCU is connected to a temperature protection circuit, which is connected to an NTC pin of the main control module MCU. The temperature protection circuit is provided with an NTC thermistor. The corresponding relationship between temperature and resistance value is established by changing the resistance value of the NTC thermistor with temperature, thereby determining the current temperature value.

7. The high-pressure pump constant pressure and constant speed dual-mode control circuit according to claim 5, characterized in that: The main control module MCU is connected to the back electromotive force circuit, and the back electromotive force circuit is connected to the SA, SB, and SC pins of the main control module MCU. The motor commutation moment is obtained by back electromotive force detection to achieve motor speed control.

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