An intelligent automatic control system and implementation method for a submersible motor pump used in brine wells

Abstract

The present application discloses an intelligent automatic control system and implementation method for a submersible motor pump used for lifting brine in a brine well, belonging to the technical field of motor control. It includes a frequency converter. The L terminal and N terminal of the frequency converter are connected to an AC220V power supply. The S terminal and T terminal of the frequency converter are connected to a submersible motor pump W1. A current transformer CT1 is connected in series between the submersible motor pump W1 and the T terminal of the frequency converter. The current transformer CT1 is connected to an AC / DC converter, and the AC / DC converter is connected to the in-phase terminal of a comparison operational amplifier OP1, the inverting terminal of a comparison operational amplifier OP2, and the in-phase terminal of a comparison operational amplifier OP3. It has the following advantages: It can automatically adjust the blade speed of the submersible motor pump according to the brine viscosity to keep the brine output flow constant when the viscosity changes, and automatically adjust the speed of the submersible motor pump to maintain the balance of the brine well liquid level. By monitoring the current of the submersible motor pump, it can prevent the submersible motor pump motor from being burned out due to idling and jamming.

Description

Technical Field

[0001] The present invention is an intelligent automatic control system and implementation method for a submersible motor pump used for lifting brine in a brine well, belonging to the field of motor control. Background Art

[0002] A brine well, also known as a salt well, is a well drilled for extracting underground salt mines. Lifting brine from a brine well means using mining equipment such as a submersible motor pump for brine extraction to pump brine from the salt well underground to the ground for extracting inorganic salts and rare elements. China is rich in salt lake resources and has a long history of brine extraction from salt wells. With the development of modern industry, the demand for mineral resources has increased, and the number of brine wells is also increasing continuously. Since the salt fields are located in remote areas, there are numerous brine wells that are relatively scattered and far apart from each other, making it difficult to manage and control the brine wells. Often, due to inadequate supervision and maintenance, the brine extraction output decreases, and the brine extraction equipment is damaged.

[0003] The existing technology is to manually inspect the site, check the values of the voltage meter and ammeter of the submersible motor pump on-site, visually observe the brine flow rate and the liquid level of the brine well, and manually adjust the brine extraction parameters, but it has the following disadvantages:

[0004] 1. Low efficiency

[0005] By manually inspecting the site and manually adjusting the brine extraction parameters, a large amount of manpower and material resources need to be invested, with a long cycle and low efficiency;

[0006] 2. High energy consumption

[0007] In the fixed working mode of the submersible motor pump, it cannot adapt to the dynamic changes of the brine. The submersible motor pump starts and stops frequently, resulting in energy waste;

[0008] 3. The equipment is prone to damage

[0009] In the case of siltation, the rotation speed of the submersible motor pump becomes slower or even blocked, and the large current is likely to burn out; in the case of too large brine extraction flow rate, the submersible motor pump for brine extraction runs dry and idles, losing the lubrication and cooling of water, and the submersible motor pump for brine extraction is prone to overheating and damage. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide an intelligent automatic control system and implementation method for a submersible motor pump used for lifting brine in a brine well, which can automatically adjust the blade rotation speed of the submersible motor pump according to the brine viscosity, keep the brine output flow rate constant when the viscosity changes, and automatically adjust the rotation speed of the submersible motor pump to maintain the balance of the brine well liquid level, and prevent the submersible motor pump motor from burning out due to idling and blocking by monitoring the current of the submersible motor pump.

[0011] To solve the above technical problems, the present invention adopts the following technical solutions:

[0012] An intelligent automatic control system for a submersible electric pump used for lifting water from a brine well, including a frequency converter. The L terminal and N terminal of the frequency converter are connected to an AC220V power supply. The S terminal and T terminal of the frequency converter are connected to a submersible electric pump W1. A current transformer CT1 is connected in series between the submersible electric pump W1 and the T terminal of the frequency converter. The current transformer CT1 is connected to an AC / DC converter, and the AC / DC converter is connected to the non-inverting terminal of a comparison operational amplifier OP1, the inverting terminal of a comparison operational amplifier OP2, and the non-inverting terminal of a comparison operational amplifier OP3;

[0013] The intelligent automatic control system further includes a laser altimeter HT1. The laser altimeter HT1 is installed at the brine wellhead. The V-OUT terminal of the laser altimeter HT1 is connected to one end of a resistor R1, and the other end of the resistor R1 is connected to the FV terminal of the frequency converter;

[0014] The PWM terminal of the frequency converter is connected to a conductivity detection electrode CP1, and the conductivity detection electrode CP1 is immersed below the brine liquid level near the submersible electric pump W1.

[0015] Further, the FWD terminal of the frequency converter is connected to one end of the normally open contact KM1-1 of a forward rotation relay. The other end of the normally open contact KM1-1 of the forward rotation relay is connected to one end of the normally closed contact KM2-2 of a reverse rotation relay. The other end of the normally closed contact KM2-2 of the reverse rotation relay is connected to the COM terminal of the frequency converter and grounded. The REV terminal of the frequency converter is connected to one end of the normally open contact KM2-1 of the reverse rotation relay. The other end of the normally open contact KM2-1 of the reverse rotation relay is connected to the COM terminal of the frequency converter and grounded.

[0016] Further, the inverting terminal of the comparison operational amplifier OP1 is connected to one end of a resistor R2 and one end of a variable resistor RV3. The other end of the resistor R2 is connected to a DC24V power supply, and the other end of the variable resistor RV3 is grounded. The output terminal of the comparison operational amplifier OP1 is connected to the positive electrode of a diode D1. The negative electrode of the diode D1 is connected to the negative electrode of a diode D2 and the G pole of a field effect transistor FET1. The D pole of the field effect transistor FET1 is connected to a DC24V power supply, and the S pole of the field effect transistor FET1 is connected to one end of a forward rotation relay coil KM1-0. The other end of the forward rotation relay coil KM1-0 is grounded.

[0017] Further, the output terminal of the comparison operational amplifier OP2 is connected to the positive electrode of the diode D2. The non-inverting terminal of the comparison operational amplifier OP2 is connected to one end of a resistor R3 and one end of a variable resistor RV4. The other end of the resistor R3 is connected to a DC24V power supply, and the other end of the variable resistor RV4 is grounded.

[0018] Further, one end of a resistor R4 and one end of a variable resistor RV5 are connected to the inverting terminal of the comparison operational amplifier OP3. The other end of the resistor R4 is connected to the DC24V power supply, and the other end of the variable resistor RV5 is grounded. The output terminal of the comparison operational amplifier OP3 is connected to the G pole of a field effect transistor FET2. The D pole of the field effect transistor FET2 is connected to the DC24V power supply, and one end of the reverse relay coil KM2-0 is connected to the S pole of the field effect transistor FET2. The other end of the reverse relay coil KM2-0 is grounded.

[0019] Further, the other end of the resistor R1 is also connected to one end of a variable resistor RV2. The other end of the variable resistor RV2 is grounded. The VCC terminal of the laser altimeter HT1 is connected to the DC24V power supply, and the GND terminal of the laser altimeter HT1 is grounded.

[0020] One end of the conductivity detection electrode CP1 is connected to the DC24V power supply, and the other end of the conductivity detection electrode CP1 is connected to one end of a variable resistor RV1 and the PWM terminal of the frequency converter. The other end of the variable resistor RV1 is grounded.

[0021] A method for realizing an intelligent automatic control system of a submersible electric pump for lifting water from a brine well includes the following steps:

[0022] Step 1, automatically adjust the blade speed of the submersible electric pump W1 according to the brine viscosity to maintain the brine output flow rate:

[0023] The conductivity detection electrode CP1 is immersed below the brine liquid level near the submersible electric pump W1. Due to the conductivity of the brine, a resistor Rp with a certain resistance value is formed at both ends of the conductivity detection electrode CP1. The higher the brine concentration, the smaller the resistance value of the resistor Rp, and vice versa, the lower the brine concentration, the larger the resistance value of the resistor Rp.

[0024] The variable resistor RV1 and the resistor Rp are connected in series to form a voltage dividing circuit. The DC24V power supply is connected to the PWM terminal of the frequency converter through the voltage division of the variable resistor RV1 to generate a ground voltage Vp. The higher the brine concentration, the lower the voltage divided by the resistor Rp, and the higher the ground voltage Vp. Vice versa, the lower the brine concentration, the lower the ground voltage Vp. The calculation formula is as follows:

[0025] ;

[0026] When the brine concentration increases due to geological reasons, the resistance value of the resistor Rp becomes smaller, the ground voltage Vp generated at the PWM terminal of the frequency converter increases, the frequency converter adjusts the sine pulse width duty cycle of the output voltage, increases the effective value of the voltage of the submersible electric pump W1, the blade speed of the submersible electric pump W1 increases, compensates for the increase in brine viscosity, and keeps the water lifting volume unchanged.

[0027] Under a certain viscosity of the brine, the voltage of the PWM terminal of the frequency converter to the ground is Vp1, and the sine pulse width duty cycle for the frequency converter to adjust the output voltage is PW1. After the viscosity of the brine changes, the voltage of the PWM terminal of the frequency converter to the ground becomes Vp2, then the sine pulse width duty cycle PW2 is required, satisfying the formula , which can ensure that the water extraction volume remains unchanged;

[0028] By adjusting the resistance value of the adjustable resistor RV1, the voltage division ratio of the adjustable resistor RV1 can be adjusted, the Vp value of the voltage to the ground under the same brine concentration can be modified, and the blade speed of the submersible pump W1 can be adjusted to ensure that the water extraction volume remains unchanged.

[0029] Furthermore, the implementation method further includes step 2 of automatically adjusting the blade speed of the submersible pump W1 according to the height of the brine level:

[0030] The voltage output from the V-OUT terminal of the laser altimeter HT1 is divided by the resistor R1 and the adjustable resistor RV2. The voltage Vh of the adjustable resistor RV2 to the ground is connected to the FV terminal of the frequency converter. When the brine level changes, the voltage of the V-OUT terminal of the laser altimeter HT1 changes, the voltage Vh of the adjustable resistor RV2 to the ground changes, the output frequency of the FV terminal of the frequency converter is adjusted, and the speed of the submersible pump W1 is adjusted to keep the liquid level at a constant position;

[0031] By adjusting the resistance value of the adjustable resistor RV2, the voltage division ratio of the adjustable resistor RV2 can be adjusted, and there is: ;

[0032] Set the intermediate appropriate value of the brine level. At this time, the median voltage of the FV terminal of the frequency converter is Vh0, and the voltage output from the V-OUT terminal of the laser altimeter HT1 is V0. By adjusting the resistance value of the adjustable resistor RV2, the voltage Vh of the adjustable resistor RV2 to the ground is made equal to the median voltage Vh0 of the FV terminal of the frequency converter. At this voltage, the output frequency of the frequency converter remains unchanged, that is ;

[0033] Set the upper limit value of the brine level. The voltage output from the V-OUT terminal of the laser altimeter HT1 is V1, and the voltage of the FV terminal of the frequency converter is , which is greater than the median voltage Vh0. The output voltage of the frequency converter increases, and the impeller speed of the submersible pump W1 increases, causing the brine level to gradually decrease;

[0034] Set the lower limit value of the brine level. The voltage output from the V-OUT terminal of the laser altimeter HT1 is V2, and the voltage of the FV terminal of the frequency converter is , which is less than the median voltage Vh0. The output frequency of the frequency converter decreases, and the impeller speed of the submersible pump W1 decreases, causing the brine level to gradually increase;

[0035] After n cycles of detection and adjustment, Vh2 gradually increases and approaches Vh0. When the brine level reaches the middle, the voltage at the FV terminal of the frequency converter is equal to the median voltage Vh0, and the output frequency of the frequency converter remains unchanged. The brine level remains constant at the middle value.

[0036] Furthermore, the implementation method further includes Step 3: The submersible pump W1 rotates in reverse to clear silt:

[0037] The current transformer monitors the operating current of the submersible pump W1. When siltation occurs, the current increases to the threshold value, and the reverse function of the frequency converter is activated. The blades of the submersible pump W1 rotate in reverse to discharge the siltation.

[0038] The current transformer CT1 is installed on the wire between the frequency converter and the submersible pump W1. The current generated by the operation of the submersible pump W1 generates an alternating induced electromotive force on the current transformer CT1 due to alternating mutual induction. The magnitude of the alternating induced voltage is proportional to the operating current of the submersible pump W1.

[0039] The AC / DC converter converts the alternating induced voltage on the current transformer CT1 into a DC voltage U1 and connects it to the non-inverting terminal of the comparator operational amplifier OP3.

[0040] The resistor R4 and the adjustable resistor RV5 form a voltage-dividing circuit. The inverting terminal of the comparator operational amplifier OP3 is connected to the upper end of the adjustable resistor RV5, and the inverting voltage of the comparator operational amplifier OP3 is U2.

[0041] When the non-inverting voltage U1 of the comparator operational amplifier OP3 is greater than the inverting voltage U2, the output terminal of the comparator operational amplifier OP3 is at a high level, the field-effect transistor FET2 conducts, the reverse relay coil KM2-0 is energized, and the normally open contact KM2-1 of the reverse relay conducts. The REV terminal of the frequency converter is short-circuited to the COM terminal of the frequency converter through the normally open contact KM2-1 of the reverse relay. The frequency converter outputs a reverse voltage and frequency, and the submersible pump W1 rotates in reverse to discharge the siltation inside the blades of the submersible pump W1.

[0042] When the siltation is discharged and the current of the submersible pump W1 decreases, the inverting voltage U2 of the comparator operational amplifier OP3 is greater than the non-inverting voltage U1. The output terminal of the comparator operational amplifier OP3 is at a low level, the field-effect transistor FET2 connected to the output terminal of the comparator operational amplifier OP3 is cut off, the reverse relay coil KM2-0 is not energized, the normally open contact KM2-1 of the reverse relay is disconnected, and the frequency converter stops outputting in the reverse direction.

[0043] Furthermore, the implementation method further includes Step 4: Monitoring the current of the submersible pump W1 to prevent the submersible pump W1 from running idle or being blocked and burned out when it exposes above the water surface:

[0044] Let the no-load current of the submersible motor pump W1 be A1 and the locked-rotor current be A2. Then, the operating current of the submersible motor pump W1 that is greater than A1 and less than A2 is regarded as the normal operating current;

[0045] The resistor R2 and the adjustable resistor RV3 form a voltage-dividing circuit to provide an inverting reference voltage U3 to the inverting input terminal of the comparator operational amplifier OP1. The resistor R3 and the adjustable resistor RV4 form a voltage-dividing circuit to provide a non-inverting reference voltage U4 to the non-inverting input terminal of the comparator operational amplifier OP2. By adjusting the resistance values of the adjustable resistor RV3 and the adjustable resistor RV4, U3 < U4;

[0046] The current transformer CT1 is installed on the wire between the frequency converter and the submersible motor pump W1. The current generated by the operation of the submersible motor pump W1 generates an alternating induced electromotive force on CT1 due to alternating mutual induction. The magnitude of the alternating induced voltage is proportional to the operating current of the submersible motor pump W1;

[0047] The AC / DC converter converts the alternating induced voltage on the current transformer CT1 into a DC voltage U1, and simultaneously connects it to the inverting input terminal of the comparator operational amplifier OP2 and the non-inverting input terminal of the comparator operational amplifier OP1. The comparator operational amplifier OP1 and the comparator operational amplifier OP2 form a window comparator circuit; when U3 < U1 < U4, that is, when U1 is between U3 and U4, the comparator operational amplifier OP1 and the comparator operational amplifier OP2 both output a high level, the positive rotation relay coil KM1-0 is energized, and the normally open contact KM1-1 of the positive rotation relay is turned on. The FWD terminal of the frequency converter is short-circuited to the common terminal COM through the normally open contact KM1-1 of the positive rotation relay, and the submersible motor pump W1 operates normally;

[0048] When U1 < U3 or U1 > U4, and the submersible motor pump W1 is in the no-load state, the comparator operational amplifier OP1 and the comparator operational amplifier OP2 both output a low level, the positive rotation relay coil KM1-0 is disconnected, and the submersible motor pump W1 stops operating.

[0049] Adopting the above technical solutions, compared with the prior art, the present invention has the following technical effects:

[0050] The present invention can automatically adjust the blade speed of the submersible motor pump according to the brine viscosity, keep the brine output flow constant when the viscosity changes, and automatically adjust the speed of the submersible motor pump to maintain the balance of the brine well liquid level. By monitoring the current of the submersible motor pump, it can prevent the submersible motor pump from being burned out due to no-load and locked-rotor.

[0051] 1. Realize automatic control: Realize the automation of the brine extraction process, reduce manual intervention, improve the economic benefits of brine extraction efficiency, and reduce the manual inspection cost by 60%.

[0052] 2. Reduced energy consumption: By using sensors to monitor the liquid level height and brine viscosity of the brine well in real time, the brine extraction parameters are optimized, reducing the energy consumption of brine extraction. Through precise control, energy waste is reduced by 20%.

[0053] 3. Achieved equipment protection: By collecting sensor data to adjust the brine flow rate to control the liquid level height of the brine well, it avoids the damage of the submersible motor pump caused by dry running; and monitors the equipment current. In case of siltation, it starts reverse flushing; in case of blocked rotation and overcurrent, it quickly cuts off the power supply of the submersible motor pump to avoid motor burnout, extends the equipment life by 30%, and reduces the equipment failure rate by 70%. Description of the Drawings

[0054] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0055] Figure 1 It is the circuit diagram of the intelligent automatic control system for lifting water from the brine well in the present invention. Specific Embodiments

[0056] Embodiment, as Figure 1 shown, an intelligent automatic control system for a submersible motor pump for lifting water from a brine well includes a frequency converter. The L terminal and N terminal of the frequency converter are connected to an AC220V power supply. The S terminal and T terminal of the frequency converter are connected to a submersible motor pump W1. A current transformer CT1 is connected in series between the submersible motor pump W1 and the T terminal of the frequency converter. The current transformer CT1 is connected to an AC / DC converter. The FWD terminal of the frequency converter is connected to one end of the normally open contact KM1-1 of the forward rotation relay. The other end of the normally open contact KM1-1 of the forward rotation relay is connected to one end of the normally closed contact KM2-2 of the reverse rotation relay. The other end of the normally closed contact KM2-2 of the reverse rotation relay is connected to the COM terminal of the frequency converter and grounded. The REV terminal of the frequency converter is connected to one end of the normally open contact KM2-1 of the reverse rotation relay. The other end of the normally open contact KM2-1 of the reverse rotation relay is connected to the COM terminal of the frequency converter and grounded.

[0057] The intelligent automatic control system further includes a comparison operational amplifier OP1. The non-inverting input terminal of the comparison operational amplifier OP1 is connected to the AC / DC converter. One end of a resistor R2 and one end of a variable resistor RV3 are connected to the inverting input terminal of the comparison operational amplifier OP1. The other end of the resistor R2 is connected to the DC24V power supply, and the other end of the variable resistor RV3 is grounded. The output terminal of the comparison operational amplifier OP1 is connected to the positive electrode of a diode D1. The negative electrode of the diode D1 is connected to the negative electrode of a diode D2 and the G pole of a field effect transistor FET1. The D pole of the field effect transistor FET1 is connected to the DC24V power supply, and one end of the positive rotation relay coil KM1-0 is connected to the S pole of the field effect transistor FET1. The other end of the positive rotation relay coil KM1-0 is grounded.

[0058] The intelligent automatic control system further includes a comparison operational amplifier OP2. The inverting input terminal of the comparison operational amplifier OP2 is connected to the AC / DC converter. The output terminal of the comparison operational amplifier OP2 is connected to the positive electrode of a diode D2. One end of a resistor R3 and one end of a variable resistor RV4 are connected to the non-inverting input terminal of the comparison operational amplifier OP2. The other end of the resistor R3 is connected to the DC24V power supply, and the other end of the variable resistor RV4 is grounded.

[0059] The intelligent automatic control system further includes a comparison operational amplifier OP3. The non-inverting input terminal of the comparison operational amplifier OP3 is connected to the AC / DC converter. One end of a resistor R4 and one end of a variable resistor RV5 are connected to the inverting input terminal of the comparison operational amplifier OP3. The other end of the resistor R4 is connected to the DC24V power supply, and the other end of the variable resistor RV5 is grounded. The output terminal of the comparison operational amplifier OP3 is connected to the G pole of a field effect transistor FET2. The D pole of the field effect transistor FET2 is connected to the DC24V power supply, and one end of the reverse rotation relay coil KM2-0 is connected to the S pole of the field effect transistor FET2. The other end of the reverse rotation relay coil KM2-0 is grounded.

[0060] The intelligent automatic control system further includes a laser altimeter HT1. The laser altimeter HT1 is installed at the brine wellhead. One end of a resistor R1 is connected to the V-OUT terminal of the laser altimeter HT1. The other end of the resistor R1 is connected to the FV terminal of a frequency converter and one end of a variable resistor RV2. The other end of the variable resistor RV2 is grounded. The VCC terminal of the laser altimeter HT1 is connected to the DC24V power supply, and the GND terminal of the laser altimeter HT1 is grounded.

[0061] The intelligent automatic control system further includes a conductivity detection electrode CP1. One end of the conductivity detection electrode CP1 is connected to the DC24V power supply. The other end of the conductivity detection electrode CP1 is connected to one end of a variable resistor RV1 and the PWM terminal of a frequency converter. The other end of the variable resistor RV1 is grounded. The conductivity detection electrode CP1 is immersed below the brine liquid level near the submersible pump W1.

[0062] The PWM terminal of the frequency converter is a sine pulse width modulation input terminal. By adjusting the voltage value of the PWM terminal of the frequency converter with respect to the ground, the sine pulse width of the output voltage of the frequency converter can be modulated, and the rotational speed of the submersible pump W1 can be changed; the FV terminal of the frequency converter is a frequency modulation input terminal. By adjusting the voltage value of the FV terminal with respect to the ground, the frequency of the output voltage of the frequency converter can be modulated, and the rotational speed of the submersible pump W1 can be changed; the FWD terminal of the frequency converter is a forward rotation signal input terminal. When the FWD terminal is short-circuited with the common terminal COM, the frequency converter outputs a positive-phase frequency voltage, and the submersible pump W1 rotates forward for water pumping operation; the REV terminal of the frequency converter is a reverse rotation signal input terminal. When the REV terminal is short-circuited with the common terminal COM, the frequency converter outputs an inverse-phase frequency voltage, and the submersible pump W1 rotates in reverse for silt cleaning operation.

[0063] A method for implementing an intelligent automatic control system for a submersible pump used for lifting brine in a brine well includes the following steps:

[0064] Step 1, automatically adjust the blade rotational speed of the submersible pump W1 according to the brine viscosity to maintain the brine output flow rate:

[0065] The conductivity detection electrode CP1 is immersed below the brine liquid level near the submersible pump W1. Since the brine has conductivity, a resistor Rp with a certain resistance value is formed at both ends of the conductivity detection electrode CP1. The higher the brine concentration, the smaller the resistance value of the resistor Rp, and vice versa, the lower the brine concentration, the larger the resistance value of the resistor Rp.

[0066] The adjustable resistor RV1 and the resistor Rp are connected in series to form a voltage dividing circuit. The DC24V power supply is connected to the PWM terminal of the frequency converter through the adjustable resistor RV1 to generate a voltage Vp with respect to the ground. The higher the brine concentration, the lower the voltage divided by the resistor Rp, and the higher the voltage Vp with respect to the ground; vice versa, the lower the brine concentration, the lower the voltage Vp with respect to the ground. The calculation formula is as follows:

[0067] .

[0068] Because the increase of solute will enhance the cohesion of the brine, the higher the concentration, the greater the viscosity of the brine, and the greater the resistance to the blades of the submersible pump W1. If the submersible pump W1 does not increase the voltage to increase the blade rotational speed, the water pumping volume will become smaller.

[0069] When the brine concentration increases due to geological reasons, since the resistance value of the resistor Rp becomes smaller, the voltage Vp generated at the PWM terminal of the frequency converter increases. The frequency converter adjusts the duty cycle of the sine pulse width of the output voltage, increases the effective value of the voltage of the submersible pump W1, and the blade rotational speed of the submersible pump W1 increases to compensate for the increase in brine viscosity and keep the water pumping volume unchanged.

[0070] Under a certain viscosity of brine, the voltage of the PWM terminal of the frequency converter to the ground is Vp1, and the sine pulse width duty ratio for the frequency converter to adjust the output voltage is PW1. After the viscosity of the brine changes, the voltage of the PWM terminal of the frequency converter to the ground becomes Vp2, and then the sine pulse width duty ratio PW2 is required, satisfying the formula , which can ensure that the water extraction volume remains unchanged.

[0071] By adjusting the resistance value of the adjustable resistor RV1, the voltage division ratio of the adjustable resistor RV1 can be adjusted, the Vp value of the voltage to the ground under the same brine concentration can be modified, and the blade speed of the submersible pump W1 can be adjusted to ensure that the water extraction volume remains unchanged.

[0072] Step 2: Automatically adjust the blade speed of the submersible pump W1 according to the height of the brine level, so as to keep the brine well level at the intermediate value, realize smooth operation of the submersible pump W1, and save power consumption:

[0073] The laser altimeter HT1 is installed at the brine wellhead to monitor the height of the brine level. The lower the brine level, the greater the distance between the liquid level and the laser altimeter HT1, and the smaller the output voltage of the V-OUT terminal of the laser altimeter HT1. On the contrary, the higher the brine level, the smaller the distance between the liquid level and the laser altimeter HT1, and the greater the output voltage of the V-OUT terminal of the laser altimeter HT1.

[0074] The output voltage of the V-OUT terminal of the laser altimeter HT1 is divided by the resistor R1 and the adjustable resistor RV2. The voltage Vh of the adjustable resistor RV2 to the ground is connected to the FV terminal of the frequency converter. When the brine level changes, the voltage of the V-OUT terminal of the laser altimeter HT1 changes, the voltage Vh of the adjustable resistor RV2 to the ground changes, the output frequency of the FV terminal of the frequency converter is adjusted, and the speed of the submersible pump W1 is adjusted to keep the liquid level at a constant position.

[0075] Furthermore, by adjusting the resistance value of the adjustable resistor RV2, the voltage division ratio of the adjustable resistor RV2 can be adjusted, and there is: ;

[0076] Set the appropriate intermediate value of the brine level. At this time, the median voltage of the FV terminal of the frequency converter is Vh0, and the output voltage of the V-OUT terminal of the laser altimeter HT1 is V0. By adjusting the resistance value of the adjustable resistor RV2, the voltage Vh of the adjustable resistor RV2 to the ground is made equal to the median voltage Vh0 of the FV terminal of the frequency converter. At this voltage, the output frequency of the frequency converter remains unchanged, that is ;

[0077] Set the upper limit value of the brine level. The output voltage of the V-OUT terminal of the laser altimeter HT1 is V1, and the voltage of the FV terminal of the frequency converter is , which is greater than the median voltage Vh0. The output voltage of the frequency converter increases, and the impeller speed of the submersible pump W1 increases, causing the brine level to gradually decrease.

[0078] Set the lower limit value of the brine level. The voltage output from the V-OUT terminal of the laser altimeter HT1 is V2, and the voltage of the FV terminal of the frequency converter is , which is less than the median voltage Vh0. The output frequency of the frequency converter decreases, and the impeller speed of the submersible pump W1 decreases, causing the brine level to gradually rise.

[0079] After n cycles of detection and adjustment, Vh2 gradually rises and approaches Vh0. When the brine level reaches the middle, the voltage of the FV terminal of the frequency converter is equal to the median voltage Vh0, the output frequency of the frequency converter remains unchanged, and the brine level remains unchanged at the middle value.

[0080] Step 3, reverse the submersible pump W1 for silt cleaning:

[0081] Due to blockage of the blades of the submersible pump W1 by sludge, debris, etc., the rotational resistance of the submersible pump W1 becomes larger, the water extraction volume becomes smaller, and the brine level rises. At this time, if the rotational speed of the submersible pump W1 is increased to increase the water extraction volume, it will cause serious blockage and the blades of the submersible pump W1 will be stuck. In the present invention, the operating current of the submersible pump W1 is monitored by a current transformer. When siltation occurs, the current increases to the threshold value, and the reverse function of the frequency converter is started. The blades of the submersible pump W1 rotate in reverse to discharge the siltation.

[0082] The current transformer CT1 is installed on the wire between the frequency converter and the submersible pump W1. The current generated by the operation of the submersible pump W1 generates an alternating induced electromotive force on the current transformer CT1 due to alternating mutual induction. The magnitude of the alternating induced voltage is proportional to the operating current of the submersible pump W1.

[0083] The AC / DC converter converts the alternating induced voltage on the current transformer CT1 into a DC voltage U1 and connects it to the non-inverting terminal of the comparator operational amplifier OP3.

[0084] The resistor R4 and the adjustable resistor RV5 form a voltage dividing circuit. The inverting terminal of the comparator operational amplifier OP3 is connected to the upper end of the adjustable resistor RV5, and the inverting voltage of the comparator operational amplifier OP3 is U2.

[0085] When the non-inverting voltage U1 of the comparator operational amplifier OP3 is greater than the inverting voltage U2, the output terminal of the comparator operational amplifier OP3 is at a high level, the field effect transistor FET2 is turned on, the reverse relay coil KM2-0 is energized, and the normally open contact KM2-1 of the reverse relay is turned on. The REV terminal of the frequency converter is short-circuited to the COM terminal of the frequency converter through the normally open contact KM2-1 of the reverse relay. The frequency converter outputs a reverse voltage and frequency, and the submersible pump W1 rotates in reverse to discharge the siltation inside the blades of the submersible pump W1.

[0086] When the sediment is discharged, the current of the submersible motor pump W1 decreases. The inverting voltage U2 of the comparator operational amplifier OP3 is greater than the non-inverting voltage U1. The output terminal of the comparator operational amplifier OP3 is at a low level. The field effect transistor FET2 connected to the output terminal of the comparator operational amplifier OP3 is cut off. The reverse relay coil KM2-0 does not attract. The normally open contact KM2-1 of the reverse relay is disconnected. The frequency converter stops reverse output.

[0087] Step 4, monitor the current of the submersible motor pump W1 to prevent the submersible motor pump W1 from running idle and burning out when exposed above the water surface, and prevent the submersible motor pump W1 from burning out due to blocked rotation:

[0088] The geological conditions of the brine well are complex, and there may be a phenomenon of formation water leakage and a sudden significant drop in the brine level. At this time, the submersible motor pump W1 runs idle above the water surface. Because it loses the lubrication and cooling of water, the submersible motor pump W1 will burn out after running idle for a period of time. Due to sludge and debris blocking the blades of the submersible motor pump W1, after the submersible motor pump W1 is dredged, the debris is not discharged, and the submersible motor pump W1 has a blocked rotation and a large current. If the power supply is not stopped in time, the submersible motor pump W1 will overheat and burn out.

[0089] Let the no-load current of the submersible motor pump W1 be A1 and the blocked-rotation current be A2. Then, the working current of the submersible motor pump W1 that is greater than A1 and less than A2 is regarded as the normal working current.

[0090] The resistor R2 and the adjustable resistor RV3 form a voltage-dividing circuit to provide an inverting reference voltage U3 for the inverting terminal of the comparator operational amplifier OP1. The resistor R3 and the adjustable resistor RV4 form a voltage-dividing circuit to provide a non-inverting reference voltage U4 for the non-inverting terminal of the comparator operational amplifier OP2. By adjusting the resistance values of the adjustable resistor RV3 and the adjustable resistor RV4, U3 < U4.

[0091] The current transformer CT1 is installed on the wire between the frequency converter and the submersible motor pump W1. The current generated by the operation of the submersible motor pump W1 generates an alternating induced electromotive force on CT1 due to AC mutual induction. The magnitude of the alternating induced voltage is proportional to the operating current of the submersible motor pump W1.

[0092] The AC / DC converter converts the alternating induced voltage on the current transformer CT1 into a DC voltage U1, and at the same time connects it to the inverting terminal of the comparator operational amplifier OP2 and the non-inverting terminal of the comparator operational amplifier OP1. The comparator operational amplifier OP1 and the comparator operational amplifier OP2 form a window comparison circuit; when U3 < U1 < U4, that is, when U1 is between U3 and U4, the comparator operational amplifier OP1 and the comparator operational amplifier OP2 both output high levels. The forward relay coil KM1-0 attracts. The normally open contact KM1-1 of the forward relay conducts. The FWD terminal of the frequency converter is short-circuited to the common terminal COM through the normally open contact KM1-1 of the forward relay. The submersible motor pump W1 operates normally.

[0093] When U1 < U3 or U1 > U4 and the submersible pump W1 is in the idling state, the comparison operational amplifiers OP1 and OP2 both output low levels simultaneously, the forward relay coil KM1-0 disconnects, and the submersible pump W1 stops running.

[0094] For the three threshold voltage signals, the reverse voltage threshold U2, the idling voltage threshold U3, and the blocked-rotor voltage threshold U4, there is U3 < U2 < U4. Each threshold is adjusted and set through the adjustable resistors RV5, RV3, and RV4 connected thereto.

[0095] The electronic control system determines the working state of the submersible pump W1 according to the magnitude of the voltage U1 at the output end of the AC / DC converter. When U1 < U3, the determination result is that the submersible pump W1 is idling; when U1 is greater than U3 and less than U2, the submersible pump W1 is normal; when U1 is greater than U2 and less than U4, the submersible pump W1 is silted and reversed; when U1 is greater than U4, the submersible pump W1 is blocked-rotor.

[0096] After the submersible pump W1 is reversed for silt cleaning, its working current turns to a normal value, and the submersible pump W1 automatically turns to the forward rotation state and continues to work.

[0097] When the submersible pump W1 stops due to idling and blocked-rotor, since the current drops to zero, the system will not start by itself. It is forced to start through the RMT terminal of the frequency converter for remote communication control. If the idling and blocked-rotor states disappear, the frequency converter can resume normal operation.

[0098] If the idling and blocked-rotor states continue to exist, an alarm message is sent through the RMT port of the frequency converter for remote communication control to remind manual on-site inspection.

[0099] The description of the present invention is given for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are chosen and described in order to best explain the principles of the invention and its practical application, and to enable those of ordinary skill in the art to understand the invention so as to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for implementing an intelligent automatic control system of a submersible electric pump for lifting water from a brine well, characterized in that: The implementation method is applied to an intelligent automatic control system for a submersible motor pump used for lifting brine in a brine well. The intelligent automatic control system includes a frequency converter. The L terminal and N terminal of the frequency converter are connected to an AC220V power supply. The S terminal and T terminal of the frequency converter are connected to a submersible motor pump W1. A current transformer CT1 is connected in series between the submersible motor pump W1 and the T terminal of the frequency converter. The current transformer CT1 is connected to an AC / DC converter. The AC / DC converter is connected to the non-inverting terminal of a comparator operational amplifier OP1, the inverting terminal of a comparator operational amplifier OP2, and the non-inverting terminal of a comparator operational amplifier OP3; The intelligent automatic control system further includes a laser altimeter HT1. The laser altimeter HT1 is installed at the brine wellhead. The V-OUT terminal of the laser altimeter HT1 is connected to one end of a resistor R1. The other end of the resistor R1 is connected to the FV terminal of the frequency converter; The PWM terminal of the frequency converter is connected to a conductivity detection electrode CP1. The conductivity detection electrode CP1 is immersed below the brine liquid level near the submersible motor pump W1; The other end of the resistor R1 is also connected to one end of a variable resistor RV2. The other end of the variable resistor RV2 is grounded. The VCC terminal of the laser altimeter HT1 is connected to a DC24V power supply. The GND terminal of the laser altimeter HT1 is grounded; One end of the conductivity detection electrode CP1 is connected to a DC24V power supply. The other end of the conductivity detection electrode CP1 is connected to one end of a variable resistor RV1 and the PWM terminal of the frequency converter. The other end of the variable resistor RV1 is grounded; The implementation method includes the following steps: Step 1, automatically adjust the blade speed of the submersible motor pump W1 according to the brine viscosity to maintain the brine output flow rate: The conductivity detection electrode CP1 is immersed below the brine liquid level near the submersible motor pump W1. Since brine has conductivity, a resistor Rp with a certain resistance value is formed at both ends of the conductivity detection electrode CP1. The higher the brine concentration, the smaller the resistance value of the resistor Rp. Conversely, the lower the brine concentration, the larger the resistance value of the resistor Rp; The variable resistor RV1 and the resistor Rp are connected in series to form a voltage division circuit. The DC24V power supply is divided by the variable resistor RV1 and connected to the PWM terminal of the frequency converter to generate a ground voltage Vp. The higher the brine concentration, the lower the voltage divided by the resistor Rp, and the higher the ground voltage Vp. Conversely, the lower the brine concentration, the lower the ground voltage Vp; When the brine concentration increases due to geological reasons, the resistance value of the resistor Rp becomes smaller, the ground voltage Vp generated at the PWM terminal of the frequency converter increases, the frequency converter adjusts the sine pulse width duty ratio of the output voltage, increases the effective value of the voltage of the submersible motor pump W1, the blade speed of the submersible motor pump W1 increases, compensates for the increase in brine viscosity, and keeps the water extraction volume unchanged; Under a certain viscosity of brine, the voltage of the PWM terminal of the frequency converter to the ground is Vp1, and the sine pulse width duty ratio of the output voltage adjusted by the frequency converter is PW1. After the viscosity of the brine changes, the voltage of the PWM terminal of the frequency converter to the ground becomes Vp2, and the sine pulse width duty ratio PW2 is required, satisfying the formula , which can ensure that the water extraction volume remains unchanged; By adjusting the resistance value of the variable resistor RV1, the voltage division ratio of the variable resistor RV1 can be adjusted, the ground voltage Vp value under the same brine concentration can be modified, and the blade speed of the submersible motor pump W1 can be adjusted to ensure that the water extraction volume remains unchanged; Step 2, automatically adjust the blade speed of the submersible motor pump W1 according to the brine liquid level height; Step 3, reverse the submersible motor pump W1 for silt cleaning; Step 4, monitor the current of the submersible motor pump W1 to prevent the submersible motor pump W1 from running idle or being blocked and burned out when it exposes above the water surface.

2. The implementation method of an intelligent automatic control system for a submersible electric pump used for lifting water in a brine well, characterized in that: The FWD terminal of the frequency converter is connected to one end of the normally open contact KM1-1 of the forward rotation relay. The other end of the normally open contact KM1-1 of the forward rotation relay is connected to one end of the normally closed contact KM2-2 of the reverse rotation relay. The other end of the normally closed contact KM2-2 of the reverse rotation relay is connected to the COM terminal of the frequency converter and grounded. The REV terminal of the frequency converter is connected to one end of the normally open contact KM2-1 of the reverse rotation relay. The other end of the normally open contact KM2-1 of the reverse rotation relay is connected to the COM terminal of the frequency converter and grounded.

3. The implementation method of an intelligent automatic control system for a submersible electric pump used for lifting water from a brine well as claimed in claim 1, characterized in that: One end of a resistor R2 and one end of a variable resistor RV3 are connected to the inverting terminal of the comparator operational amplifier OP1. The other end of the resistor R2 is connected to the DC24V power supply. The other end of the variable resistor RV3 is grounded. The output terminal of the comparator operational amplifier OP1 is connected to the positive electrode of a diode D1. The negative electrode of the diode D1 is connected to the negative electrode of a diode D2 and the G pole of a field effect transistor FET1. The D pole of the field effect transistor FET1 is connected to the DC24V power supply. One end of the S pole of the field effect transistor FET1 is connected to one end of the forward rotation relay coil KM1-0. The other end of the forward rotation relay coil KM1-0 is grounded.

4. The implementation method of an intelligent automatic control system for a submersible motor pump used for lifting water from a brine well as claimed in claim 1, characterized in that: The output terminal of the comparator operational amplifier OP2 is connected to the positive electrode of the diode D2. One end of a resistor R3 and one end of a variable resistor RV4 are connected to the non-inverting terminal of the comparator operational amplifier OP2. The other end of the resistor R3 is connected to the DC24V power supply. The other end of the variable resistor RV4 is grounded.

5. The implementation method of an intelligent automatic control system for a submersible motor pump used for lifting water from a brine well, characterized in that: One end of a resistor R4 and one end of a variable resistor RV5 are connected to the inverting terminal of the comparator operational amplifier OP3. The other end of the resistor R4 is connected to the DC24V power supply. The other end of the variable resistor RV5 is grounded. The output terminal of the comparator operational amplifier OP3 is connected to the G pole of a field effect transistor FET2. The D pole of the field effect transistor FET2 is connected to the DC24V power supply. One end of the S pole of the field effect transistor FET2 is connected to one end of the reverse rotation relay coil KM2-0. The other end of the reverse rotation relay coil KM2-0 is grounded.

6. The implementation method of an intelligent automatic control system for a submersible motor pump used for lifting water in a brine well, characterized in that: The calculation formula for the voltage Vp to the ground in Step 1 is as follows: 。 7. The implementation method of an intelligent automatic control system for a submersible motor pump used in brine wells as described in claim 1, characterized in that: In Step 2, the specific process of automatically adjusting the blade speed of the submersible pump W1 according to the height of the brine level is as follows: The voltage output from the V-OUT terminal of the laser altimeter HT1 is divided by the resistor R1 and the variable resistor RV2. The voltage Vh to the ground of the variable resistor RV2 is connected to the FV terminal of the frequency converter. When the brine level changes, the voltage of the V-OUT terminal of the laser altimeter HT1 changes, and the voltage Vh to the ground of the variable resistor RV2 changes. The output frequency of the FV terminal of the frequency converter is adjusted, and the speed of the submersible pump W1 is adjusted to keep the liquid level at a constant position. By adjusting the resistance value of the adjustable resistor RV2, the voltage division ratio of the adjustable resistor RV2 can be adjusted, and there is: ; Set the intermediate appropriate value of the brine level. At this time, the median voltage of the FV terminal of the frequency converter is Vh0, and the output voltage of the V-OUT terminal of the laser altimeter HT1 is V0. By adjusting the resistance value of the adjustable resistor RV2, make the voltage Vh of the adjustable resistor RV2 to the ground equal to the median voltage Vh0 of the FV terminal of the frequency converter. At this voltage, the output frequency of the frequency converter remains unchanged, that is ; Set the upper limit value of the brine level. The voltage output from the V-OUT terminal of the laser altimeter HT1 is V1, and the voltage of the FV terminal of the frequency converter is , which is greater than the median voltage Vh0. The output voltage of the frequency converter increases, and the impeller speed of the submersible pump W1 rises, causing the brine level to gradually decrease; Set the lower limit value of the brine level. The voltage output from the V-OUT terminal of the laser altimeter HT1 is V2, and the voltage of the FV terminal of the frequency converter is , which is less than the median voltage Vh0. The output frequency of the frequency converter decreases, and the impeller speed of the submersible pump W1 decreases, causing the brine level to gradually rise; After n cycles of detection and adjustment, Vh2 gradually increases and approaches Vh0. When the brine level reaches the middle, the voltage of the FV terminal of the frequency converter is equal to the median voltage Vh0, and the output frequency of the frequency converter remains unchanged. The brine level remains unchanged at the middle value.

8. The implementation method of an intelligent automatic control system for a submersible motor pump used in brine well water lifting, characterized in that: In Step 3, the specific process of the reverse cleaning of the submersible pump W1 is as follows: The current transformer monitors the operating current of the submersible pump W1. When siltation occurs and the current increases to the threshold value, the reverse function of the frequency converter is started, and the blades of the submersible pump W1 rotate in reverse to discharge the siltation. The current transformer CT1 is installed on the wire between the frequency converter and the submersible pump W1. The current generated by the operation of the submersible pump W1 generates an alternating induced electromotive force on the current transformer CT1 due to AC mutual induction. The magnitude of the alternating induced voltage is proportional to the operating current of the submersible pump W1; The AC / DC converter converts the alternating induced voltage on the current transformer CT1 into a DC voltage U1 and connects it to the non-inverting input terminal of the comparator operational amplifier OP3; The resistor R4 and the adjustable resistor RV5 form a voltage dividing circuit. The inverting input terminal of the comparator operational amplifier OP3 is connected to the upper end of the adjustable resistor RV5, and the inverting voltage of the comparator operational amplifier OP3 is U2; When the non-inverting voltage U1 of the comparator operational amplifier OP3 is greater than the inverting voltage U2, the output terminal of the comparator operational amplifier OP3 is at a high level, the field effect transistor FET2 conducts, the reverse relay coil KM2-0 is energized, and the normally open contact KM2-1 of the reverse relay conducts. The REV terminal of the frequency converter is short-circuited to the COM terminal of the frequency converter through the normally open contact KM2-1 of the reverse relay. The frequency converter outputs a reverse voltage and frequency, and the submersible pump W1 rotates in reverse to discharge the sediment inside the impeller of the submersible pump W1; When the sediment is discharged, the current of the submersible pump W1 decreases. The inverting voltage U2 of the comparator operational amplifier OP3 is greater than the non-inverting voltage U1. The output terminal of the comparator operational amplifier OP3 is at a low level. The field effect transistor FET2 connected to the output terminal of the comparator operational amplifier OP3 is cut off. The reverse relay coil KM2-0 is not energized, and the normally open contact KM2-1 of the reverse relay is disconnected. The frequency converter stops reverse output.

9. The implementation method of an intelligent automatic control system for a submersible electric pump used for lifting water from a brine well according to claim 1, characterized in that: In step 4, the specific process of monitoring the current of the submersible pump W1 to prevent the submersible pump W1 from idling or being blocked and burned out when exposed above the water surface is as follows: Let the no-load current of the submersible pump W1 be A1 and the blocked-rotor current be A2. Then, the operating current of the submersible pump W1 that is greater than A1 and less than A2 is regarded as the normal operating current; The resistor R2 and the adjustable resistor RV3 form a voltage dividing circuit to provide an inverting reference voltage U3 for the inverting input terminal of the comparator operational amplifier OP1. The resistor R3 and the adjustable resistor RV4 form a voltage dividing circuit to provide a non-inverting reference voltage U4 for the non-inverting input terminal of the comparator operational amplifier OP2. By adjusting the resistance values of the adjustable resistor RV3 and the adjustable resistor RV4, U3 < U4; The current transformer CT1 is installed on the wire between the frequency converter and the submersible pump W1. The current generated by the operation of the submersible pump W1 generates an alternating induced electromotive force on the CT1 due to AC mutual induction. The magnitude of the alternating induced voltage is proportional to the operating current of the submersible pump W1; The AC / DC converter converts the alternating induced voltage on the current transformer CT1 into a DC voltage U1, and simultaneously connects it to the inverting terminal of the comparator operational amplifier OP2 and the non-inverting terminal of the comparator operational amplifier OP1. The comparator operational amplifier OP1 and the comparator operational amplifier OP2 form a window comparison circuit; when U3 < U1 < U4, that is, when U1 is between U3 and U4, both the comparator operational amplifier OP1 and the comparator operational amplifier OP2 output a high level, the forward relay coil KM1-0 is energized, and the normally open contact KM1-1 of the forward relay is turned on. The FWD terminal of the frequency converter is short-circuited through the normally open contact KM1-1 of the forward relay and the common terminal COM, and the submersible pump W1 operates normally; When U1 < U3 or U1 > U4, and the submersible pump W1 is in an idling state, both the comparator operational amplifier OP1 and the comparator operational amplifier OP2 output a low level, the forward relay coil KM1-0 is disconnected, and the submersible pump W1 stops operating.

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