Battery-powered water pump electric quantity control method

Abstract

The invention belongs to the technical field of water pumps, and particularly relates to a battery-powered water pump electric quantity control method which comprises the following steps: S1, connecting a battery to a water pump, S2, detecting the current voltage to obtain V1; s3, starting a water pump; s4, accelerated operation of the water pump; s5, calculating Vs according to a formula; s6, if the current rotating speed reaches the rated rotating speed or the current power reaches the rated power, executing S7; otherwise, executing S14; s7, detecting the current voltage to obtain V2; s8, the water pump operates stably; s9, performing real-time monitoring to obtain Qi; s10, calculating the ratio of Vc, Vb, Qi and Vc according to a formula; s11, if Vb is greater than Y, executing S15; otherwise, executing S12; s12, if Vb is greater than Z, executing S13; otherwise, executing S8; s13, if the ratio of Qi to Vc is smaller than the dimension, executing S15; otherwise, executing S8; s14, if Vc is greater than X, executing S15; otherwise, executing S4; and S15, setting a low electric quantity mark. Whether various batteries are in a low-power state or not can be accurately judged, and the batteries are effectively prevented from being discharged completely.

Description

Technical Field

[0001] The present invention belongs to the technical field of water pumps, and particularly relates to a method for controlling the power of a battery-powered water pump. Background Art

[0002] Battery-powered water pumps are increasingly used, and the application of using the battery of an electric vehicle as a power source is also becoming more and more widespread. There is a problem with using the battery of an electric vehicle as a power source, that is, it is afraid that the battery power will be exhausted and the electric vehicle cannot be ridden back, which brings trouble to users. Therefore, a method is needed to judge the battery power and reserve the power for the user to go back.

[0003] For different types of batteries and different numbers of battery cells, the voltage values in the low-power state are different. When the type and number of battery cells are known, it can be judged whether it is in the low-power state by detecting whether the battery voltage value is lower than the set voltage value. However, due to the variety of battery types of electric vehicles and the uncertainty of the number of battery cells, the set voltage value cannot be determined, so this method cannot be used for control. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for controlling the power of a battery-powered water pump, which can accurately judge whether various batteries are in the low-power state and effectively avoid the exhaustion of battery power.

[0005] The present invention is implemented as follows:

[0006] A method for controlling the power of a battery-powered water pump includes the following steps:

[0007] S1. Connect the water pump to the battery, initialize the single-chip microcomputer, and set the dimension M, voltage drop rates X, Y, Z, rated speed S0, and rated power P0, where the voltage drop rates X, Y, Z satisfy: X > Y > Z;

[0008] S2. Detect the current voltage to obtain the initial battery voltage V1;

[0009] S3. Start the water pump and continuously monitor the current I i , the current voltage V i , the current speed S i and the current power P i ;

[0010] S4. Accelerate the operation of the water pump;

[0011] S5. According to the formula V s = (V1 - V i ) * 100% / V1, calculate the voltage drop rate V s during the accelerated operation;

[0012] S6. If the current speed S iReach the rated speed S0 or the current power P i If the rated power P0 is reached, then execute step S7; otherwise execute step S14;

[0013] S7. Detect the current voltage to obtain the operating voltage V2;

[0014] S8. The water pump runs stably;

[0015] S9. Monitor in real time to obtain the discharge power Q i ;

[0016] S10. According to the formula V c =V2 - V i , calculate the voltage difference V c ; According to the formula V b =V c *100% / V2, calculate the stable operating voltage drop rate V b ; According to the formula R = Q i / V c , calculate the ratio R of the discharge power Q i to the voltage difference V c ;

[0017] S11. If the stable operating voltage drop rate V b is greater than the voltage drop rate Y, then execute step S15; otherwise execute step S12;

[0018] S12. If the stable operating voltage drop rate V b is greater than the voltage drop rate Z, then execute step S13; otherwise execute step S8;

[0019] Sll. If the ratio R of the discharge power Q i to the voltage difference V c is less than the dimension M, then execute step S15; otherwise execute step S8;

[0020] S14. If the accelerating operating voltage drop rate V s is greater than the voltage drop rate X, then execute step S15; otherwise execute step S4;

[0021] S15. Set the low - power flag and stop driving the water pump.

[0022] In the above - mentioned method for controlling the power of a battery - powered water pump, in step S3, the current current I i and the current voltage V i are obtained by taking the average. Set a buffer to store N latest current values and N latest voltage values. When there is a new value, the oldest value is sent out. Take the average of the N current values after removing the extreme values to obtain the current current I i, the extreme values of N voltage values are removed and averaged to obtain the current voltage V i .

[0023] In the above-mentioned method for controlling the power of a battery-powered water pump, it further includes a current detection circuit and a voltage detection circuit. The current detection circuit samples the current using a resistor RS, filters it through resistors R1 and C1, and sends it to the single-chip microcomputer. After being converted by ADC1 (analog-to-digital converter), it forms a current value; the voltage detection circuit divides the voltage using resistors R2 and R3, filters it through resistors R4 and C2, and sends it to the single-chip microcomputer. After being converted by ADC2 (analog-to-digital converter), it forms a voltage value.

[0024] In the above-mentioned method for controlling the power of a battery-powered water pump, in step S3, the current current I i and the current voltage V i are monitored once every T time to obtain a current current I i and a current voltage V i ; in step S3, the current rotational speed S i and the current power P i are monitored once every T time to obtain a current rotational speed S i and a current power P i .

[0025] In the above-mentioned method for controlling the power of a battery-powered water pump, in step S9, the discharge power Q i is obtained by an integration method, and each current current I i is multiplied by T and then accumulated respectively.

[0026] In the above-mentioned method for controlling the power of a battery-powered water pump, in step S3, the current rotational speed S i is measured by a variable frequency board or a Hall sensor connected to the water pump motor.

[0027] In the above-mentioned method for controlling the power of a battery-powered water pump, in step S3, the current power P i is measured by a variable frequency board or a power sensor connected to the water pump motor.

[0028] The prominent advantages of the present invention compared with the prior art are:[[]]

[0029] The present invention respectively judges whether the battery is in a low power state in two states of the water pump during acceleration operation and stable operation. When the water pump is in acceleration operation, if the acceleration operation voltage drop rate V sIf it is greater than the voltage drop rate X, it indicates that when the water pump is accelerating, the voltage drops too fast, and the battery is already in a low power state. There is no need to continue running, and it should be stopped in time to avoid over-discharging the battery. When the water pump is in a stable operation state, first, through the stable operation voltage drop rate V b Compare with the voltage drop rate Y. If the stable operation voltage drop rate V b is greater than the voltage drop rate Y, it indicates that when the water pump is in stable operation, the voltage drops too fast, and the battery is in a low power state. Then, when the stable operation voltage drop rate V b is less than or equal to the voltage drop rate Y, the stable operation voltage drop rate V b is compared with the voltage drop rate Z, and the discharged charge Q i is compared with the voltage difference V c The ratio R of is compared with the dimension M. When the stable operation voltage drop rate V b is greater than the voltage drop rate Z, and the ratio R of the discharged charge Q i to the voltage difference V c is less than the dimension M, it indicates that when the discharged charge Q i is constant, the voltage difference V c is too large, which is also an indication that the battery is in a low power state. Therefore, the judgment is more accurate, effectively avoiding misjudgment. At the same time, the voltage drop rate Y can be set as high as possible, so that the water pump can use more electricity while ensuring a margin. The present invention can accurately judge whether various batteries are in a low power state and effectively avoid discharging the battery completely. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the control flow chart of the present invention;

[0031] Figure 2 is the circuit schematic diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] The following further describes the present invention with specific embodiments. Refer to Figure 1 、 2 :

[0033] A method for controlling the power of a battery-powered water pump includes the following steps:

[0034] S1. Connect the water pump to the battery, initialize the single-chip microcomputer, and set the dimension M, voltage drop rate X, voltage drop rate Y, voltage drop rate Z, rated speed S0, and rated power P0. The voltage drop rates X, Y, and Z satisfy: X > Y > Z;

[0035] S2. Detect the current voltage to obtain the initial battery voltage V1;

[0036] S3. Start the water pump and continuously monitor the current I i 、the current voltage Vi and the current rotational speed S i and the current power P i ;

[0037] S4. The water pump runs at an accelerated speed;

[0038] S5. According to the formula V s = (V1 - V i ) * 100% / V1, calculate the voltage drop rate V s ;

[0039] S6. If the current rotational speed S i reaches the rated rotational speed S0 or the current power P i reaches the rated power P0, then execute step S7; otherwise execute step S14;

[0040] S7. Detect the current voltage to obtain the operating voltage V2;

[0041] S8. The water pump runs stably;

[0042] S9. Monitor in real time to obtain the discharged electricity quantity Q i ;

[0043] C S10. According to the formula V c = V2 - V i , calculate the voltage difference V c ; According to the formula V b = V c * 100% / V2, calculate the stable operating voltage drop rate V b ; According to the formula R = Q i / V c , calculate the ratio R of the discharged electricity quantity Q i to the voltage difference V c ;

[0044] S11. If the stable operating voltage drop rate V b is greater than the voltage drop rate Y, then execute step S15; otherwise execute step S12;

[0045] S12. If the stable operating voltage drop rate V b is greater than the voltage drop rate Z, then execute step S13; otherwise execute step S8;

[0046] S13. If the ratio R of the discharged electricity quantity Q i to the voltage difference V c is less than the dimension M, then execute step S15; otherwise execute step S8;

[0047] S14. If the accelerated operating voltage drop rate V s is greater than the voltage drop rate X, then execute step S15; otherwise execute step S4;

[0048] S15. Set the low - power flag and stop driving the water pump.

[0049] In this embodiment, the voltage drop rate X is 15%, the voltage drop rate Y is 5%, the voltage drop rate Z is 3%, and the dimension M is 30.

[0050] After the water pump starts, it is first in an accelerating operation state. When the current speed S i reaches the rated speed S0 or the current power P i reaches the rated power P0, the water pump will no longer accelerate, that is, when one or both of the current speed S i and the current power P i reach the specified value, the water pump will be in a stable operation state.

[0051] As Figure 1 shown, the present invention determines whether the battery is in a low - power state respectively in two states of the accelerating operation and the stable operation of the water pump. When the water pump is in the accelerating operation, if the accelerating - operation voltage drop rate V s is greater than the voltage drop rate X, it indicates that when the water pump is in the accelerating operation, the voltage drops too fast, and the battery is already in a low - power state. There is no need to continue running, and it should be stopped in time to avoid over - discharging of the battery. When the water pump is in the stable operation state, first compare the stable - operation voltage drop rate V b with the voltage drop rate Y. If the stable - operation voltage drop rate V b is greater than the voltage drop rate Y, it indicates that when the water pump is in the stable operation, the voltage drops too fast, and the battery is in a low - power state. Then when the stable - operation voltage drop rate V b is less than or equal to the voltage drop rate Y, compare the stable - operation voltage drop rate V b with the voltage drop rate Z, and compare the ratio R of the discharged charge Q i to the voltage difference V c with the dimension M. When the stable - operation voltage drop rate V b is greater than the voltage drop rate Z and the ratio R of the discharged charge Q i to the voltage difference V c is less than the dimension M, it indicates that when the discharged charge Q i is certain, the voltage difference V c is too large, which is also an indication that the battery is in a low - power state. Therefore, the judgment is more accurate, effectively avoiding misjudgment. At the same time, the voltage drop rate Y can be set as high as possible, so that the water pump can use more electricity while ensuring a margin.

[0052] To obtain the accurate current I i and the current voltage V i , in step S3, the current I iand the current voltage V i It is obtained by taking the average. A buffer is set up to store N latest current values and N latest voltage values. When there is a new value, the oldest value is sent out. The extreme values of the N current values are removed and the average is taken to obtain the current I i The extreme values of the N voltage values are removed and the average is taken to obtain the current voltage V i .

[0053] Detection methods of current and voltage: As Figure 2 shown, it also includes a current detection circuit and a voltage detection circuit. The current detection circuit samples the current using the resistor RS, filters it through the resistors R1 and the capacitor C1 and then sends it to the single-chip microcomputer, and forms a current value after being converted by the ADC1 (analog-to-digital converter); the voltage detection circuit divides the voltage using the resistors R2 and R3, filters it through the resistor R4 and the capacitor C2 and then sends it to the single-chip microcomputer, and forms a voltage value after being converted by the ADC2 (analog-to-digital converter).

[0054] Figure 2 In, U1 is an inverter drive circuit, which is a conventional circuit. The resistor RS is a current sampling resistor. After the inverter circuit converges, it is connected to GND through the resistor RS. The current measured here is equivalent to the battery discharge current. The resistors R1 and the capacitor C1 form a filtering circuit. The filtered signal is sent to the input of the ADC1 (analog-to-digital converter) of the single-chip microcomputer to convert the analog signal into a digital signal to form a current value; the battery voltage is divided by the resistors R2 and R3, filtered through the resistor R4 and the capacitor C2 and then sent to the input of the ADC2 (analog-to-digital converter) of the single-chip microcomputer to convert the analog signal into a digital signal to form a voltage value.

[0055] In this embodiment, the single-chip microcomputer uses ES8P0283.

[0056] Furthermore, in step S3, the current I i and the current voltage V i are monitored once every T time to obtain a current I i and a current voltage V i ; in step S3, the current rotational speed S i and the current power P i are monitored once every T time to obtain a current rotational speed S i and a current power P i .

[0057] Discharged electric quantity Q i Obtaining method: In step S9, the discharged electric quantity Q i is obtained by integration. Each current I i is multiplied by T and then accumulated. When T is 1 s, each current I iThe discharged electricity Q can be obtained by accumulation. i When T is 100 ms, each current I i is multiplied by 100 ms respectively and then accumulated to obtain the discharged electricity Q. i In this embodiment, T is 1 s, and the discharged electricity Q i is the accumulation of each current I i after the water pump operates stably.

[0058] Measurement method of the current speed S i : In step S3, the current speed S i is measured by a frequency conversion board or a Hall sensor connected to the water pump motor. In this embodiment, the current speed S i is read by the frequency conversion board.

[0059] Measurement method of the current power P i : In step S3, the current power P i is measured by a frequency conversion board or a power sensor connected to the water pump motor. In this embodiment, the current power P i is read by the frequency conversion board.

[0060] The above embodiments are only one of the preferred embodiments of the present invention, and do not limit the scope of implementation of the present invention. Therefore, all equivalent changes made according to the shape, structure, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for controlling the power of a battery-powered water pump, characterized in that: Including the following steps: S1. Connect the water pump to the battery, initialize the single-chip microcomputer, and set the dimension M, voltage drop rate X, voltage drop rate Y, voltage drop rate Z, rated speed S0, and rated power P0. The voltage drop rates X, Y, and Z satisfy: X > Y > Z; S2. Detect the current voltage to obtain the initial battery voltage V1; S3. Start the water pump and monitor the current I in real time i , the current voltage V i , the current speed S i and the current power P i ; S4. The water pump runs at an accelerated speed; S5. Calculate the acceleration operating voltage drop rate V s according to the formula V i = (V1 - V s ) * 100% / V1; S6. If the current speed S i reaches the rated speed S0 or the current power P i reaches the rated power P0, then execute step S7; Otherwise, execute step S14; S7. Detect the current voltage to obtain the operating voltage V2; S8. The water pump runs stably; S9. The discharged electricity Q is obtained through real-time monitoring i ; S10. Calculate the voltage difference V c according to the formula V i = V2 - V c ; calculate the stable operating voltage drop rate V b according to the formula V c = V b * 100% / V2; calculate the ratio R of the discharge charge Q i to the voltage difference V c according to the formula R = Q i / V c ; S11. If the stable operating voltage drop rate V b is greater than the voltage drop rate Y, then execute step S15; otherwise, execute step S12; S12. If the stable operating voltage drop rate V b is greater than the voltage drop rate Z, then execute step S13; Otherwise, execute step S8; S13. If the ratio R of the discharge charge Q i to the voltage difference V c is less than the dimension M, then execute step S15; otherwise, execute step S8; S14. If the acceleration operating voltage drop rate V s is greater than the voltage drop rate X, then execute step S15; otherwise, execute step S4; S15. Set the low battery flag and stop driving the water pump.

2. The method for controlling the power of a battery-powered water pump according to claim 1, characterized in that: In step S3, the current current I i and the current voltage V i are obtained by taking the average. A buffer is set up to store the N latest current values and the N latest voltage values. When a new value arrives, the oldest value is sent out. The current current I is obtained by taking the average of the N current values in the buffer after removing the extreme values i , and the current voltage V is obtained by taking the average of the N voltage values after removing the extreme values i .

3. A battery-powered water pump power control method according to claim 2, characterized in that: It also includes a current detection circuit and a voltage detection circuit. The current detection circuit samples the current using the resistor RS, filters it through the resistor R1 and the capacitor C1, sends it to the single-chip microcomputer, and forms a current value after being converted by ADC1; the voltage detection circuit divides the voltage using the resistor R2 and the resistor R3, filters it through the resistor R4 and the capacitor C2, sends it to the single-chip microcomputer, and forms a voltage value after being converted by ADC2.

4. A method for controlling the power of a battery-powered water pump according to claim 1, characterized in that: In step S3, the current I is monitored in real time i and the current voltage V i Once every T time intervals, a current I is monitored i and a current voltage V i ; In step S3, the current rotational speed S is monitored in real time i and the current power P i Once every T time intervals, a current rotational speed S is monitored i and a current power P i .

5. A method for controlling the power of a battery-powered water pump according to claim 4, characterized in that: In step S9, the discharge charge Q i is obtained by an integration method, where each current I i is multiplied by T and then accumulated respectively.

6. A battery-powered water pump power control method according to claim 1, characterized in that: In step S3, the current rotational speed S i is measured by a variable frequency board or a Hall sensor connected to the water pump motor.

7. A method for controlling the power of a battery-powered water pump according to claim 1, characterized in that: In step S3, the current power P i is measured by a variable frequency board or a power sensor connected to the water pump motor.

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