Design method of sensorless deep-well pump constant-pressure water supply and dual-power-supply switching control system

Abstract

The invention discloses a design method of a sensorless deep-well pump constant-pressure water supply and dual-power-supply switching control system. The system comprises a sensorless vector control module, a constant-pressure module, a dual-power-supply switching module and a system architecture module. Under the scene of the deep-well pump, the method does not depend on a rotor position sensor and a waterway pressure sensor, so that the deep-well pump can directly supply constant-pressure water to a household pipe network; the deep-well pump controller adopts dual-power-supply power supply and automatic switching, solar direct-current power supply is preferentially achieved, automatic undisturbed switching to alternating-current power grid power supply is achieved when solar energy is insufficient, and the deep-well pump controller has the reverse flow prevention, soft access, surge limiting and anti-jitter switching capacity; household constant-pressure water supply is achieved through an algorithm by means of a single deep-well pump, the equipment and maintenance cost is reduced, and a system architecture of water tower water storage and a household booster pump is replaced.

Description

Technical Field

[0001] This invention belongs to the field of pump frequency conversion control technology, specifically relating to a design method for a sensorless deep well pump constant pressure water supply and dual power supply switching control system. Background Technology

[0002] Deep well pumps, also known as submersible pumps, are commonly used to extract groundwater from deep wells for domestic, irrigation, or industrial use. In traditional solutions, a method of "deep well pumping at a constant speed, water storage in a water tower or tank, and secondary pressurization by a domestic booster pump" is typically used to achieve household water supply. With the development of solar power generation and motor frequency conversion control, solar water pump controllers and frequency conversion constant pressure water supply controllers have emerged on the market. However, in deep well pump applications, the motor is often underwater or underground, the cable is long, the environment is humid, and maintenance is difficult. If relying on position sensors such as encoders and resolvers or water pressure sensors, although the reliability is improved, the cost is also significantly increased.

[0003] Existing technologies include the following solutions: Deep well pumps use power frequency or simple frequency conversion to pump water to water towers or storage tanks, and booster pumps on the household side use closed-loop speed regulation based on pressure sensors to achieve constant pressure water supply; pressure sensors are configured in the deep well pump controller, and frequency converters are used to regulate speed so that the pipeline pressure is maintained at the set value. The motors are mostly induction motors or permanent magnet synchronous motors, and some solutions require rotor position or speed sensors to achieve high-performance control; photovoltaic arrays are boosted through maximum power point tracking to drive frequency converters to run pumps. Some products stop when there is insufficient sunlight or require manual switching to mains power. Some products use relays or contactors to switch between photovoltaic and AC power, but this is prone to problems such as DC bus impact, backflow, and frequent vibration.

[0004] Based on the above solutions, the existing technology has the following drawbacks: High dependence on sensors; position sensors are difficult to install on the underwater motor end and have a high failure rate; pressure sensors are prone to drift or damage when operating in humid, water hammer, or silty environments, resulting in high maintenance costs; Unsmooth start-up and mode switching; Sensorless vector control has very small back EMF at low and zero speeds, making direct closed-loop control prone to instability; If open-loop V / f or simple If start-up is used, angle jumps are likely to occur when switching to the observer angle, causing torque pulses, pipeline pressure fluctuations, and water hammer; Unreliable solar / AC switching; Simple relay switching can cause DC bus capacitor charging and discharging impacts, voltage drops, and overshoots; Without backflow prevention and soft connection, the solar side may be reverse-charged or AC side devices may be overstressed, and frequent switching under critical illumination can cause vibration; Complex and costly system; Water towers and booster pumps require additional equipment and installation space, posing a risk of secondary pollution; Two-stage pump systems have high energy consumption, numerous maintenance points, and slow response. Summary of the Invention

[0005] In the context of deep well pumps, this invention enables the deep well pump to directly supply constant pressure water to the household water supply network without relying on rotor position sensors and water pressure sensors. The deep well pump controller adopts dual power supply and automatic switching, prioritizing solar DC power supply and automatically and seamlessly switching to AC grid power supply when solar energy is insufficient. It also has anti-backflow, soft access, surge limiting, and anti-vibration switching capabilities. By using a single deep well pump and algorithms to achieve constant pressure water supply to the household, it reduces equipment and maintenance costs and replaces the system architecture of water tower storage and household booster pumps.

[0006] The technical problem solved by this invention can be achieved by the following technical solution: a design method for a sensorless deep well pump constant pressure water supply and dual power supply switching control system, comprising a sensorless vector control module, a constant pressure module, a dual power supply switching module, and a system architecture module, characterized in that: The sensorless vector control module includes the following steps: A1. Establish a DC bus and complete self-checks for undervoltage, overvoltage, overcurrent, and overtemperature. A2. When the motor is stationary or at low speed, use If start to set the d-axis current command id*=0 and the q-axis current command iq*=Iq in the virtual synchronous coordinate system d*q*. start The electric angular velocity ramp ωe*(t) is set and integrated to obtain the virtual angle θ. e* The inner loop of the current control limits the acceleration and current, enabling the motor to start and accelerate to the threshold speed ω under heavy load conditions. th ; A3. Construct a back EMF state observer using the voltage-current relationship of the permanent magnet synchronous motor in the αβ coordinate system, and estimate the back EMF e. α and e β The phase of the back electromotive force is locked by a phase-locked loop, and the estimated electrical angle θ is output. e With estimation of electric angular velocity ω e ; A4. When the motor accelerates to the threshold speed ω th Furthermore, when the back electromotive force is observable, the angle alignment compensator is activated, causing the angle difference Δθ to gradually converge to 0, where Δθ = θ e -θ e* ; A5. When |Δθ| is less than the threshold εθ and this continues for T... align Then, the vector control angle source is transferred from θ. e* Switch to θ e This achieves a seamless transition from open-loop to sensorless closed-loop operation, where T align The duration threshold for angle alignment determination; The constant voltage module includes the following steps: B1. The estimated electric angular velocity ω is obtained through a sensorless vector control module.e The estimated torque T is obtained by combining the q-axis current iq with the motor torque constant Kt, and the estimated mechanical power P is obtained from this. m =T·ω e ; B2. By estimating the electric angular velocity ω e And estimate mechanical power P m Given the flow rate Q and head H, calculate the pressure p = ρgH; B3. Set the target pressure p*, calculate the pressure error ep=p*−p, obtain the speed command ω* through proportional-integral regulation, and generate iq* to adjust the pump output by passing through the speed loop or torque loop or directly as a reference for the sensorless vector control module. The dual-power switching module includes solar modules and an AC grid, and also includes the following steps: C1. The output of the solar module enters the DC-DC converter. The controller adjusts the converter through the maximum power point tracking algorithm to convert the power into a controllable DC voltage suitable for the DC bus, which is then connected to the DC bus through the first ideal diode. C2. The AC input of the AC power grid is filtered by electromagnetic interference and then enters the rectifier bridge. The DC voltage is obtained through the energy storage capacitor, and its output is connected to the DC bus through the second ideal diode. C3. A pre-charge branch is set up between the energy storage capacitor and the DC bus. The pre-charge branch includes a pre-charge resistor and a controllable switch. When |V is detected... Cac -V bus When |V is large, the controllable switch is closed, and the bus capacitor is charged through the pre-charging resistor. Cac -V bus When the voltage drops below the threshold, the second ideal diode or the bypass pre-charge resistor is activated, where V... Cac V is the voltage of the energy storage capacitor. bus This is the DC bus voltage; C4, the first ideal diode, and the second ideal diode form a parallel OR-ing; C5, Power Management Controller Real-Time Sampling of V pv I pv and / or P pv V bus A signal exists between the AC power grid and the voltage hysteresis threshold V is set. low and V high Power hysteresis threshold P min and P high Delay determination time T low and T high and minimum holding time T min V pv For the voltage of the solar module, I pv For the current of the solar module, Ppv Power of the solar panel; It also includes a system architecture module, which comprises a deep well pump, a deep well pump controller, and a household pipe network, and includes the following steps: D1. The deep well pump is connected to the deep well pump controller located on the ground via a cable; D2. The deep well pump controller connects to the solar panel input and the AC grid input, and supplies power from the DC bus to the inverter drive unit. D3. Water from the deep well pump enters the household pipe network.

[0007] Step A5 also includes introducing an angle compensation amount θ. c After the shock-free switching, the vector control angle is (θ). e +θ c ), by iterative adjustment, the equivalent q-axis voltage component u q′ Maximize or make the equivalent d-axis voltage component u d′ It approaches 0 to eliminate the residual position error δ.

[0008] When the phase-locked loop loses lock, the bus is undervoltage, overcurrent, lacks water, or runs dry, the controller will reduce power and limit speed or revert to step A2.

[0009] In step B2, the deep well pump characteristic data is preset or calibrated in the controller. This data includes a mapping table of rotational speed n and torque T with flow rate Q and head H. The electrical angular velocity ω is estimated. e Estimate the torque T, and obtain the head H by looking up a table or interpolation.

[0010] In step B2, based on the similarity law of centrifugal pumps and the characteristics of the pipeline network, H = H0·(n / n0) 2 −k·Q 2 P m =T·ω e =ρgQH / η, where n0 is the rated speed, H0 is the head at the rated speed, k is the head-flow characteristic coefficient, and η is the efficiency of the deep well pump.

[0011] In step B3, any one or more of the following can be applied to ω*: dω / dt limiting, dead zone, anti-integral saturation, and minimum start / stop time.

[0012] When the solar panel power is insufficient or V bus When the voltage approaches the undervoltage threshold, the controller limits ω* or iq* by power limiting or voltage drooping, and automatically restores it to the target pressure when the AC grid is connected or sunlight is restored.

[0013] Step C5 also includes an inverter; when there is insufficient sunlight, P pv Below the load requirement, V bus Drop to threshold Vlow And continue T low At that time, the power management controller closes the controllable switch, triggering pre-charging of the AC power grid branch until V... Cac ≈V bus After the second ideal diode is turned on or the AC grid contactor is closed, the DC bus is kept continuously powered by OR-ing during the switching process.

[0014] When light returns, P pv Above the threshold P high And V pv Within the maximum power point tracking available range and for a sustained T high At this time, the power management controller adjusts the maximum power point tracking output to be slightly higher than the AC grid branch output, and the solar panels are powered.

[0015] Compared with existing technologies, this invention has the following advantages: In the case of deep well pumps, this invention does not rely on rotor position sensors and water pressure sensors, enabling deep well pumps to directly supply constant pressure water to household pipe networks; the deep well pump controller adopts dual power supply and automatic switching, prioritizing solar DC power supply, and automatically and seamlessly switching to AC grid power supply when solar energy is insufficient, and has anti-backflow, soft access, surge limiting, and anti-vibration switching capabilities; using a single deep well pump to achieve constant pressure water supply to households through algorithms reduces equipment and maintenance costs, and replaces the system architecture of water tower storage and household booster pumps. Detailed Implementation

[0016] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention is further described below.

[0017] In the description of this invention, it should be understood that the terms "one end", "the other end", "outer side", "upper", "inner side", "horizontal", "coaxial", "center", "end", "length", "outer end", etc., indicating the orientation or positional relationship are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0018] This embodiment discloses a design method for a sensorless deep well pump constant pressure water supply and dual power supply switching control system, including a sensorless vector control module, a constant pressure module, a dual power supply switching module, and a system architecture module.

[0019] Based on the above, the sensorless vector control module includes the following steps: A1. Establish a DC bus and complete self-checks for undervoltage, overvoltage, overcurrent, and overtemperature. A2. When the motor is stationary or at low speed, use If start to set the d-axis current command id*=0 and the q-axis current command iq*=Iq in the virtual synchronous coordinate system d*q*. start To overcome the load, the electric angular velocity ramp ωe*(t) is set and integrated to obtain the virtual angle θ. e* The inner loop of the current control limits the acceleration and current, enabling the motor to start and accelerate to the threshold speed ω under heavy load conditions. th ; A3. Construct a back EMF state observer using the voltage-current relationship of the permanent magnet synchronous motor in the αβ coordinate system, and estimate the back EMF e. α and e β The phase of the back electromotive force is locked by a phase-locked loop, and the estimated electrical angle θ is output. e With estimation of electric angular velocity ω e For use with Park / inverse Park transformation and velocity closed loop; A4. When the motor accelerates to the threshold speed ω th Furthermore, when the back electromotive force is observable, the angle alignment compensator is activated, causing the angle difference Δθ to gradually converge to 0, where Δθ = θ e -θ e* After normalization from -π to π, the speed proportional-integral output remains continuous and iq* does not change abruptly during the alignment process, thus avoiding torque step jumps. A5. When |Δθ| is less than the threshold εθ and this continues for T... align Then, the vector control angle source is transferred from θ. e* Switch to θ e This achieves a seamless transition from open-loop to sensorless closed-loop operation, where T align The duration threshold for angle alignment determination is used to confirm that the state of |Δθ| being less than εθ is maintained continuously for a sufficient time before allowing angle source switching to be performed, thereby avoiding erroneous switching and torque and current surges caused by noise or angle estimation fluctuations. Based on the above, by collecting the inverter-side phase current, DC current, and DC bus voltage, and combining the modulation command with the inverter model, the stator voltage u is reconstructed. αβ When long cables and output filters are present, equivalent RLC parameters of the cable can be introduced to compensate and filter voltage and current, thereby improving the accuracy of back EMF estimation.

[0020] In summary, step A5, after the impact-free switching, considers the residual position error δ caused by inductor saturation, control delay, dead zone, or voltage error, and also includes the introduction of an angle compensation amount θ. c After the shock-free switching, the vector control angle is (θ). e +θ c ), by iterative adjustment, the equivalent q-axis voltage component u q′Maximizing this is equivalent to making cos δ approach 1, or making the equivalent d-axis voltage component u d′ Approaching 0, this is used to gradually eliminate the δ between the estimated angle and the actual rotor angle without needing to accurately model all sources of error, thereby improving steady-state efficiency and dynamic stability, and reducing noise.

[0021] In summary, when abnormalities such as phase-locked loop loss, bus undervoltage, overcurrent, water shortage, or dry running are detected, the controller will reduce power and limit speed or revert to step A2 to ensure system reliability and safety.

[0022] In summary, once the steady-state sensorless vector control operation is entered, id*=0 or id* is given by the field weakening strategy, iq* is given by the outer loop such as the pressure loop or speed loop, and the inner current loop maintains a fast response.

[0023] In summary, under sensorless conditions, a smooth transition from zero speed to sensorless vector control is achieved through If start-up, alignment compensation, and position error iterative compensation, thereby reducing torque pulses.

[0024] Based on the above, the constant voltage module includes the following steps: B1. The estimated electric angular velocity ω is obtained through a sensorless vector control module. e The estimated torque T is obtained by combining the q-axis current iq with the motor torque constant Kt, and the estimated mechanical power P is obtained from this. m =T·ω e ; B2. By estimating the electric angular velocity ω e And estimate mechanical power P m Given the flow rate Q and head H, calculate the pressure p = ρgH, where ρ is the liquid density and g is the gravitational acceleration. B3. Set the target pressure p*, which is set by the user, preferably 0.25-0.4MPa. Calculate the pressure error ep=p*−p, and obtain the speed command ω* through proportional-integral regulation. ω* is used as a reference for the speed loop or torque loop or directly as a sensorless vector control module to generate iq* to regulate the pump output. The proportional-integral regulation generates the speed command based on the proportional term of the current value of the pressure error and its integral term of the cumulative value over time, in order to achieve rapid response and eliminate steady-state pressure deviation.

[0025] Based on the above, during steady-state operation, the controller does not use a water pressure sensor; instead, it estimates the network pressure p through motor electrical parameters. Any of the following methods can be used: In conjunction with the above, in step B2, the deep well pump characteristic data is preset or calibrated in the controller. The deep well pump characteristic data includes a mapping table of rotational speed n and torque T with flow rate Q and head H. The head H is obtained by estimating the electrical angular velocity ωe and estimating the torque T, and then looking up the table or interpolating.

[0026] Based on the above, in step B2, according to the similarity law of centrifugal pumps and the characteristics of the pipeline network, H = H0·(n / n0) 2 −k·Q 2 P m =T·ω e =ρgQH / η, where n0 is the rated speed, H0 is the head at the rated speed, k is the head-flow characteristic coefficient, and η is the efficiency of the deep well pump.

[0027] In combination with the above, in step B3, it is preferable to add any one or more of the following to ω*: dω / dt limiting, dead zone, anti-integral saturation, and minimum start-stop time interval, in order to avoid water hammer and pressure fluctuations.

[0028] In summary, when the power of the solar modules is insufficient or V bus When the voltage approaches the undervoltage threshold, the controller limits ω* or iq* by power limiting or voltage drooping to maintain pressure stability while ensuring the safety of the inverter, and automatically restores the pressure to the target level after the AC grid is connected or sunlight is restored.

[0029] Based on the above, pressure can be estimated by comparing the motor's electrical parameters with the pump model or pump curve, thus achieving constant pressure water supply without pressure sensors.

[0030] In conjunction with the above, the dual-power switching module, including solar modules and the AC grid, also includes the following steps: C1. Solar module side power supply branch: The output of the solar module enters the DC-DC converter. The controller adjusts the converter through the maximum power point tracking algorithm so that the solar module outputs the corresponding maximum power under different light conditions. The power is converted into a controllable DC voltage suitable for the DC bus and connected to the DC bus through the first ideal diode. Preferably, the first ideal diode adopts a back-to-back MOSFET structure and has reverse blocking capability to prevent the DC bus from back-feeding to the solar module side. C2. AC power supply branch on the mains side: The AC input from the mains is filtered for electromagnetic interference and then enters the rectifier bridge. After rectification, a power factor correction circuit is preferably set up. The control circuit improves the waveform of the AC input current, making the input current in phase with the input voltage and close to a sine wave, thereby improving the power factor and reducing harmonic current. The DC voltage on the AC side is obtained through the energy storage capacitor. Its output is connected to the DC bus through the second ideal diode. Preferably, the second ideal diode adopts a back-to-back MOSFET structure to achieve low voltage drop conduction and reverse blocking to prevent reverse flow. C3. To suppress the surge current to the DC bus energy storage capacitor at the moment of connection of the AC grid-side power supply branch, a pre-charging branch is set between the energy storage capacitor and the DC bus. The pre-charging branch includes a pre-charging resistor and a controllable switch. The pre-charging resistor is connected in series with the controllable switch. When |V is detected...Cac -V bus When |V is large, the controllable switch is closed, and the bus capacitor is charged through the pre-charging resistor. Cac -V bus When the voltage drops below a threshold, the second ideal diode or the bypass pre-charge resistor is activated to achieve soft access, where V... Cac V is the voltage of the energy storage capacitor. bus This is the DC bus voltage; C4, the first ideal diode and the second ideal diode form a parallel OR-ing to achieve power supply and reverse blocking on the side with higher voltage. By controlling the maximum power point tracking output voltage to be slightly higher than the AC grid rectified output, or by increasing the maximum power point tracking output setting when the solar module power is sufficient, priority power supply to the solar module is achieved. When the solar module power is insufficient and its output voltage drops, the first ideal diode automatically turns off or reduces its conduction, and the second ideal diode automatically takes over the power supply, achieving seamless switching. C5, Power Management Controller Real-Time Sampling of V pv I pv and / or P pv V bus A signal exists between the AC power grid and the voltage hysteresis threshold V is set. low and V high Power hysteresis threshold P min and P high Delay determination time T low and T high and minimum holding time T min Specifically, when P is satisfied pv Below P min And V bus Below V low The duration is not less than T low When solar power supply is insufficient, a switch to AC power is triggered; when P is satisfied... pv Higher than P high or / and V bus Higher than V high The duration is not less than T high And the minimum holding time T has been met. min When solar power is restored, it is determined that the system has resumed operation and is allowed to switch back to solar power to avoid frequent fluctuations under critical light conditions. V pv For the voltage of the solar module, I pv For the current of the solar module, P pv Power of the solar panel; In conjunction with the above, specifically step C5 also includes an inverter; when there is insufficient sunlight, P pv Below the load requirement, V bus Descending to Vlow And continue T low At that time, the power management controller closes the controllable switch, triggering pre-charging of the AC power grid branch until V... Cac ≈V bus After the second ideal diode is turned on or the AC grid contactor is closed, the DC bus is kept continuously powered by OR-ing during the switching process, and the inverter does not need to be shut down.

[0031] In summary, when light returns, P pv Above the threshold P high And V pv Within the maximum power point tracking available range and for a sustained T high When the power management controller adjusts the maximum power point tracking output to be slightly higher than the AC grid branch output, the solar panels are powered. Preferably, the AC grid side power supply branch can also be delayed to reduce no-load losses.

[0032] In addition to the above, it also includes protection modules for reverse connection and reverse feed of solar modules, AC power grid surge and lightning strike protection, DC bus overvoltage clamping, undervoltage power limiting, overcurrent, short circuit and overtemperature fast shutdown.

[0033] In summary, the DC bus provides continuous power during the switching process between solar and AC power, avoiding downtime and shocks, improving the continuity and reliability of water supply. The use of ideal diode OR-ing and pre-charge branch enables seamless switching between solar modules and the AC grid, reducing losses, while also preventing backflow and surges.

[0034] In addition to the above, it also includes a system architecture module, which comprises a deep well pump, a deep well pump controller, and a household pipe network, and includes the following steps: D1. The deep well pump is connected to the deep well pump controller located on the ground via a cable; D2. The deep well pump controller connects to the solar panel input and the AC grid input, and supplies power from the DC bus to the inverter drive unit. D3. Water from the deep well pump enters the household pipe network.

[0035] In summary, the deep well pump operates at variable speed as needed under the constant pressure algorithm of the controller, dynamically adjusting its output according to the water supply at each point of use to achieve constant pressure water supply at the household level. Preferably, a check valve and filter are installed at the inlet of the household water supply network, and a small pressure stabilizing tank, air pressure tank, or bypass pressure relief valve is configured to absorb instantaneous water usage fluctuations, reduce water hammer, and improve comfort. Combined with automatic switching between solar and AC dual power sources, even in cases of insufficient sunlight or at night, AC power can be used to achieve continuous water supply around the clock.

[0036] In conjunction with the above, in other embodiments, it is preferable to add functional modules such as water shortage protection, dry-run protection, remote monitoring, timed disinfection, or multiple pumps in parallel. Specifically, when the estimated load torque T drops abnormally in a short period of time and is accompanied by a decrease in motor current, the water shortage protection module and the dry-run protection module can determine water shortage or dry running, execute speed reduction or shutdown, and periodically retry to protect the pump body; the remote monitoring module uploads data to P via 4G, LoRa, or WiFi. pv V bus Operating data such as speed and estimated pressure are used for operation and maintenance.

[0037] In combination with the above, in other embodiments, in high-flow-rate scenarios, multiple deep well pumps can be connected in parallel and rotated to achieve redundancy and graded speed regulation.

[0038] In summary, the system architecture module eliminates the water tower and secondary booster pump at the system level, reducing equipment and maintenance, and improving hygiene and energy efficiency.

[0039] In the context of deep well pumps, this invention enables the deep well pump to directly supply constant pressure water to the household water supply network without relying on rotor position sensors and water pressure sensors. The deep well pump controller adopts dual power supply and automatic switching, prioritizing solar DC power supply and automatically and seamlessly switching to AC grid power supply when solar energy is insufficient. It also has anti-backflow, soft access, surge limiting, and anti-vibration switching capabilities. By using a single deep well pump and algorithms to achieve constant pressure water supply to the household, it reduces equipment and maintenance costs and replaces the system architecture of water tower storage and household booster pumps.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, equivalent changes, or alterations made to the above embodiments based on the technical principles of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A design method for a sensorless deep well pump constant pressure water supply and dual power supply switching control system, comprising a sensorless vector control module, a constant pressure module, a dual power supply switching module, and a system architecture module, characterized in that: The sensorless vector control module includes the following steps: A1. Establish a DC bus and complete self-checks for undervoltage, overvoltage, overcurrent, and overtemperature. A2. When the motor is stationary or at low speed, use If start to set the d-axis current command id*=0 and the q-axis current command iq*=Iq in the virtual synchronous coordinate system d*q*. start The electric angular velocity ramp ωe*(t) is set and integrated to obtain the virtual angle θ. e* The inner loop of the current control limits the acceleration and current, enabling the motor to start and accelerate to the threshold speed ω under heavy load conditions. th ; A3. Construct a back EMF state observer using the voltage-current relationship of the permanent magnet synchronous motor in the αβ coordinate system, and estimate the back EMF e. α and e β The phase of the back electromotive force is locked by a phase-locked loop, and the estimated electrical angle θ is output. e With estimation of electric angular velocity ω e ; A4. When the motor accelerates to the threshold speed ω th Furthermore, when the back electromotive force is observable, the angle alignment compensator is activated, causing the angle difference Δθ to gradually converge to 0, where Δθ = θ e -θ e* ; A5. When |Δθ| is less than the threshold εθ and this continues for T... align Then, the vector control angle source is transferred from θ. e* Switch to θ e This achieves a seamless transition from open-loop to sensorless closed-loop operation, where T align The duration threshold for angle alignment determination; The constant voltage module includes the following steps: B1. The estimated electric angular velocity ω is obtained through a sensorless vector control module. e The estimated torque T is obtained by combining the q-axis current iq with the motor torque constant Kt, and the estimated mechanical power P is obtained from this. m =T·ω e ; B2. By estimating the electric angular velocity ω e And estimate mechanical power P m Given the flow rate Q and head H, calculate the pressure p = ρgH; B3. Set the target pressure p*, calculate the pressure error ep=p*−p, obtain the speed command ω* through proportional-integral regulation, and generate iq* to adjust the pump output by passing through the speed loop or torque loop or directly as a reference for the sensorless vector control module. Dual power switching module, including solar modules and AC grid; The system architecture module includes a deep well pump, a deep well pump controller, and a household pipe network.

2. The design method of a sensorless deep well pump constant pressure water supply and dual power supply switching control system according to claim 1, characterized in that: The dual power supply switching module also includes the following steps: C1. The output of the solar module enters the DC-DC converter. The controller adjusts the converter through the maximum power point tracking algorithm to convert the power into a controllable DC voltage suitable for the DC bus, which is then connected to the DC bus through the first ideal diode. C2. The AC input of the AC power grid is filtered by electromagnetic interference and then enters the rectifier bridge. The DC voltage is obtained through the energy storage capacitor, and its output is connected to the DC bus through the second ideal diode. C3. A pre-charge branch is set up between the energy storage capacitor and the DC bus. The pre-charge branch includes a pre-charge resistor and a controllable switch. When |V is detected... Cac -V bus When |V is large, the controllable switch is closed, and the bus capacitor is charged through the pre-charging resistor. Cac -V bus When the voltage drops below the threshold, the second ideal diode or the bypass pre-charge resistor is activated, where V... Cac V is the voltage of the energy storage capacitor. bus This is the DC bus voltage; C4, the first ideal diode, and the second ideal diode form a parallel OR-ing; C5, Power Management Controller Real-Time Sampling of V pv I pv and / or P pv V bus A signal exists between the AC power grid and the voltage hysteresis threshold V is set. low and V high Power hysteresis threshold P min and P high Delay judgment time T low and T high and minimum holding time T min V pv For the voltage of the solar module, I pv For the current of the solar module, P pv This refers to the power output of the solar panel.

3. The design method of a sensorless deep well pump constant pressure water supply and dual power supply switching control system according to claim 2, characterized in that: The system architecture module also includes the following steps: D1. The deep well pump is connected to the deep well pump controller located on the ground via a cable; D2. The deep well pump controller connects to the solar panel input and the AC grid input, and supplies power from the DC bus to the inverter drive unit. D3. Water from the deep well pump enters the household pipe network.

4. The design method of a sensorless deep well pump constant pressure water supply and dual power supply switching control system according to claim 1, characterized in that: Step A5 also includes introducing an angle compensation amount θ. c After the shock-free switching, the vector control angle is (θ). e +θ c ), by iterative adjustment, the equivalent q-axis voltage component u q′ Maximize or make the equivalent d-axis voltage component u d′ Approaching 0, used to eliminate residual position error δ; when the phase-locked loop loses lock, the bus is undervoltage, overcurrent, lacks water, or runs dry, the controller performs power reduction and speed limiting or returns to step A2.

5. The design method of a sensorless deep well pump constant pressure water supply and dual power supply switching control system according to claim 4, characterized in that: In step B2, the deep well pump characteristic data is preset or calibrated in the controller. This data includes a mapping table of rotational speed n and torque T with flow rate Q and head H. The electrical angular velocity ω is estimated. e Estimate the torque T, and obtain the head H by looking up a table or interpolation.

6. The design method of a sensorless deep well pump constant pressure water supply and dual power supply switching control system according to claim 4, characterized in that: In step B2, based on the similarity law of centrifugal pumps and the characteristics of the pipeline network, H = H0·(n / n0) 2 −k·Q 2 P m =T·ω e =ρgQH / η, where n0 is the rated speed, H0 is the head at the rated speed, k is the head-flow characteristic coefficient, and η is the efficiency of the deep well pump.

7. The design method for a sensorless deep well pump constant pressure water supply and dual power supply switching control system according to claim 5 or 6, characterized in that: In step B3, any one or more of the following can be applied to ω*: dω / dt limiting, dead zone, anti-integral saturation, and minimum start / stop time.

8. The design method of a sensorless deep well pump constant pressure water supply and dual power supply switching control system according to claim 7, characterized in that: When the solar panel power is insufficient or V bus When the voltage approaches the undervoltage threshold, the controller limits ω* or iq* by power limiting or voltage drooping, and automatically restores it to the target pressure when the AC grid is connected or sunlight is restored.

9. The design method of a sensorless deep well pump constant pressure water supply and dual power supply switching control system according to claim 2, characterized in that: Step C5 also includes an inverter; when there is insufficient sunlight, P pv Below the load requirement, V bus Drop to threshold V low And continue T low At that time, the power management controller closes the controllable switch, triggering pre-charging of the AC power grid branch until V... Cac ≈V bus After the second ideal diode is turned on or the AC grid contactor is closed, the DC bus is kept continuously powered by OR-ing during the switching process.

10. The design method of a sensorless deep well pump constant pressure water supply and dual power supply switching control system according to claim 9, characterized in that: When light returns, P pv Above the threshold P high And V pv Within the maximum power point tracking available range and for a sustained T high At this time, the power management controller adjusts the maximum power point tracking output to be slightly higher than the AC grid branch output, and the solar panels are powered.