Electronic water pump control method with two-in-one

Abstract

This invention discloses a two-wire integrated electronic water pump control method, which includes outputting a PWM signal to a driver chip, wherein when 0% < D < 8%, the driver chip outputs the maximum drive current I to the stator assembly. max The rotor assembly operates at its maximum speed n max Rotation; when 8% ≤ D < 13%, the driver chip does not output drive current I to the stator assembly, and the rotor assembly does not rotate; when 13% ≤ D ≤ 93%, the driver chip outputs drive current I to the stator assembly, and the rotor assembly rotates. Furthermore, as the duty cycle D of the PWM signal increases linearly, the driver chip outputs drive current I from the minimum drive current I... min It begins to increase linearly until it reaches the maximum drive current I. max The rotor assembly starts from the minimum speed n min It begins to increase linearly until it reaches the maximum speed n. max This invention primarily addresses the problem of providing an electronic water pump that is easy to implement linear control and provides operational status feedback. The invention uses a specific protocol, specifically a PWM signal duty cycle, to linearly control the operation of the electronic water pump and provides feedback on its operational status, thereby reducing the secondary development costs of the electronic water pump.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of precise motor control methods, and particularly to a two-wire electronic water pump control method. BACKGROUND

[0002] Electronic water pumps have high output efficiency and can achieve precise flow control, so they are widely used in automobiles, household appliances and industrial equipment. New energy vehicles usually have two or more electronic water pumps, which are the power source of the entire cooling system of new energy vehicles. The power battery and drive motor of new energy vehicles need to rely on electronic water pumps to drive the circulation of coolant for cooling.

[0003] The electronic water pump in the prior art usually includes a pump cover, a pump shell, a shaft core, a rotor assembly and a stator assembly. The pump cover and the pump shell are combined with each other and fixed to each other to form a cavity. The two ends of the shaft core are fixed on the pump cover and the pump shell. The rotor assembly is supported in the cavity between the pump cover and the pump shell through the shaft core. The stator assembly is arranged outside the cavity and can magnetically couple the rotor assembly to rotate in the cavity between the pump cover and the pump shell, so as to drive the liquid medium through the impeller on the rotor assembly to flow in a certain direction.

[0004] When controlling the operation of the electronic water pump, the voltage, current and waveform input to the stator assembly are actually controlled to drive the stator assembly to generate a rotating magnetic field with a certain shape and strength. The rotating magnetic field can magnetically couple the rotor assembly to rotate at a certain speed, and finally drive the impeller to rotate at a certain speed. For the feedback of the operating state of the electronic water pump, the voltage, current and waveform of the stator assembly are often required.

[0005] The process of controlling the voltage, current and waveform of the stator assembly to control the speed of the impeller is often not linear. The voltage, current and waveform of the stator assembly also need to be measured by a special measuring device. Therefore, for the application party of the electronic water pump, not only a special control circuit needs to be developed, but also a special program needs to be developed for the control circuit, which has high secondary development cost. In addition, many manufacturers of equipment hope to control the controlled appliance with the least signal line to further reduce the hardware cost and secondary development cost.

[0006] In summary, how to provide an electronic water pump that is easy to realize linear control and operating state feedback to reduce the secondary development cost of the application party has become a problem to be solved. SUMMARY

[0007] The present application aims to provide a two-wire electronic water pump control method which is easy to realize linear control and operating state feedback.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a two-wire integrated electronic water pump control method, which is applied to an electronic water pump; the electronic water pump includes at least a drive chip, a stator assembly, and a rotor assembly; the drive chip and the stator assembly are electrically connected according to their phase polarities, so that the drive chip can drive the stator assembly to generate a rotating magnetic field, thereby magnetically coupling the rotor assembly to rotate through the rotating magnetic field; the drive chip at least provides a signal input / output interface.

[0009] The method includes:

[0010] The host computer outputs a PWM signal to the driver chip through the signal input / output interface. The duty cycle of the PWM signal is defined as D. Then:

[0011] When 0% < D < 8%, the driver chip outputs the maximum drive current I to the stator assembly. max The rotor assembly operates at a maximum speed n max Rotate;

[0012] When 8% ≤ D < 13%, the drive chip does not output drive current I to the stator assembly, and the rotor assembly does not rotate;

[0013] When 13% ≤ D ≤ 93%, the drive chip outputs a drive current I to the stator assembly, and the rotor assembly rotates. Furthermore, as the duty cycle D of the PWM signal increases linearly, the drive chip outputs a minimum drive current I. min It begins to increase linearly until it reaches the maximum drive current I. max The rotor assembly starts from the minimum speed n min It begins to increase linearly until it reaches the maximum speed n. max ;

[0014] When 93% < D ≤ 100%, the driver chip outputs the maximum drive current I to the stator assembly. max The rotor assembly operates at a maximum speed n max Rotate;

[0015] The drive chip outputs a level change signal to the host computer through the signal input / output interface to indicate the operating status of the rotor assembly.

[0016] In the above technical solution, the level change signal specifically includes: a continuous high-level signal, a continuous low-level signal, and a high-level signal and a low-level signal that appear cyclically and have the same or different durations.

[0017] The operation state of the rotor assembly includes a normal operation state, an idle protection state, a locked-rotor protection state, an over-temperature protection state, an overload protection state, and a PWM signal receiving abnormal state.

[0018] The level change signal includes:

[0019] The normal operation state includes a 4.5s high level signal and a 0.5s low level signal.

[0020] The idle protection state includes a 1.0s high level signal and a 1.0s low level signal.

[0021] The locked-rotor protection state includes a 1.0s high level signal and a 1.5s low level signal.

[0022] The over-temperature protection state includes a 1.0s high level signal and a 2.0s low level signal.

[0023] The overload protection state includes a 1.0s high level signal and a 2.5s low level signal.

[0024] The PWM signal receiving abnormal state includes a continuous high level signal.

[0025] The specific method for determining whether to enter the idle protection state includes:

[0026] If the ratio of the square of the rotation speed n of the rotor assembly to the driving current I output by the driving chip to the stator assembly is greater than a preset first threshold value, then it is further determined whether the rotation speed n of the rotor assembly is greater than a preset second threshold value. 2 If not, the idle protection count value is increased by 1, and if yes, the idle protection count value is decreased by 1.

[0027] If the driving current I output by the driving chip to the stator assembly is less than a preset third threshold value, then the idle protection count value is increased by 1.

[0028] If the rotation speed n of the rotor assembly is greater than a preset fourth threshold value, then the idle protection count value is increased by 1.

[0029] If the above conditions are not met, then the idle protection count value is decreased by 1.

[0030] When the idle protection count value is greater than a preset fifth threshold value, the idle protection state is triggered.

[0031] In the technical solution, the first threshold value is 10000, the second threshold value is 1800 rpm, the third threshold value is 0.4A, the fourth threshold value is 6500 rpm, and the fifth threshold value is 2500.

[0032] In the technical solution, the specific method for determining whether to enter the locked-rotor protection state is:

[0033] In a clock cycle, if the ratio of the rotation speed n of the rotor assembly to the driving current I output by the driving chip to the stator assembly is less than a preset sixth threshold value, then the locked-rotor protection count value is incremented by 1;

[0034] In a clock cycle, if the rotation speed n of the rotor assembly is less than a preset seventh threshold value, then the locked-rotor protection count value is incremented by 1;

[0035] In a clock cycle, if the rotation speed n of the rotor assembly is greater than a preset eighth threshold value, then the locked-rotor protection count value is incremented by 1;

[0036] When the locked-rotor protection count value is greater than a preset ninth threshold value, the locked-rotor protection state is triggered.

[0037] In the technical solution, the sixth threshold value is 55, the seventh threshold value is 300 rpm, the eighth threshold value is 10000 rpm, and the ninth threshold value is 1000.

[0038] In the technical solution, the over-temperature protection state specifically refers to:

[0039] The temperature acquisition module built in the driving chip is used to acquire the temperature of the driving chip;

[0040] When the temperature of the driving chip is higher than 135℃, the rotation speed n of the rotor assembly is limited to 80% of the maximum rotation speed n max .

[0041] When the temperature of the driving chip is higher than 145℃, the rotation speed n of the rotor assembly is limited to 60% of the maximum rotation speed n max .

[0042] When the temperature of the driving chip is higher than 165℃, the driving chip stops outputting the driving current I, and the rotor assembly does not rotate.

[0043] In the technical solution, the high level of the PWM signal and the level change signal is greater than or equal to 0.6 times the input voltage, and the low level is less than or equal to 0.4 times the input voltage.

[0044] Compared with the prior art, the beneficial effects of the application are that the two-in-one electronic water pump control method can linearly control the driving current I and the rotating speed n of the rotor assembly by adjusting the duty cycle D of the PWM signal, can feed back the operating state of the rotor assembly through the level change signal, can linearly control the operation of the electronic water pump in the form of the duty cycle of the PWM signal through a single external interface, and can feed back the operating state of the electronic water pump, thereby reducing the secondary development cost of the electronic water pump. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 It is a schematic diagram of the system of the application.

[0046] Figure 2 It is a circuit schematic diagram of the application. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0048] The embodiment provides a two-in-one electronic water pump control method, which can allow the upper computer to linearly control the operation of the electronic water pump in the form of the duty cycle of the PWM signal and can feed back the operating state of the electronic water pump through the level change signal.

[0049] Please refer to Figure 1 and Figure 2 The electronic water pump at least comprises a driving chip, a stator assembly and a rotor assembly; wherein the driving chip is a motor special driving MCU, the model of which is P621212E series, and the driving chip is an integrated motor driver; the stator assembly is a winding based on a stator core, which has three phases (U, V, W); the rotor assembly is arranged in the cavity of the electronic water pump, which has a magnetic ring and an impeller, and can rotate under the action of the rotating magnetic field.

[0050] The driving chip is electrically connected with the stator assembly in phase poles, so that the driving chip can drive the stator assembly to generate a rotating magnetic field. Specifically, the GH1 pin, the SH1 pin and the GL1 pin of the driving chip are respectively connected with a U phase of the stator assembly through field effect tubes, the GH2 pin, the SH2 pin and the GL2 pin of the driving chip are respectively connected with a V phase of the stator assembly through field effect tubes, and the GH3 pin, the SH3 pin and the GL3 pin of the driving chip are respectively connected with a W phase of the stator assembly through field effect tubes. The driving chip leads at least a signal input / output interface (FG interface), an input signal is connected to the FG interface of the driving chip after being stabilized by a voltage stabilizing chip, and an output signal of the driving chip is output through a triode.

[0051] The two-in-one electronic water pump control method of the embodiment comprises:

[0052] The host computer outputs a PWM signal to the driving chip through the signal input / output interface, and defines a duty ratio D of the PWM signal, so that:

[0053] When 0% < D < 8%, the driving chip outputs a maximum driving current I to the stator assembly max , and the rotor assembly rotates at a maximum rotational speed n max .

[0054] When 8% ≤ D < 13%, the driving chip does not output a driving current I to the stator assembly, and the rotor assembly does not rotate.

[0055] When 13% ≤ D ≤ 93%, the driving chip outputs a driving current I to the stator assembly, the rotor assembly rotates, and as the duty ratio D of the PWM signal linearly increases, the driving chip linearly increases from a minimum driving current I min to a maximum driving current I max , and the rotor assembly linearly increases from a minimum rotational speed n min to a maximum rotational speed n max .

[0056] When 93% < D ≤ 100%, the driving chip outputs a maximum driving current I max to the stator assembly, and the rotor assembly rotates at a maximum rotational speed n max .

[0057] The driving chip outputs a level change signal to the host computer through the signal input / output interface to indicate the running state of the rotor assembly.

[0058] According to the protocol, the host computer can linearly control the rotational speed of the rotor assembly through the PWM signal.

[0059] The host computer is an MCU such as a single-chip microcomputer or an embedded chip on a household appliance, a driving computer of an automobile, a vehicle controller (VCU) of a new energy automobile, and a programmable controller (PLC) or an industrial computer on an industrial device, and the host computer has at least a PWM signal output interface with adjustable duty cycle and an input interface capable of acquiring high and low level signals.

[0060] Specifically, the level change signal specifically includes: a continuous high level signal, a continuous low level signal, and a high level signal and a low level signal that cyclically appear and have the same or different durations.

[0061] Specifically, the operating state of the rotor assembly specifically includes: a normal operating state, an idling protection state, a locked-rotor protection state, an over-temperature protection state, an overload protection state, and a PWM signal reception abnormal state.

[0062] Further specifically, the level change signal specifically is:

[0063] Normal operating state: 4.5s high level signal and 0.5s low level signal that cyclically appear;

[0064] Idling protection state: 1.0s high level signal and 1.0s low level signal that cyclically appear;

[0065] Locked-rotor protection state: 1.0s high level signal and 1.5s low level signal that cyclically appear;

[0066] Over-temperature protection state: 1.0s high level signal and 2.0s low level signal that cyclically appear;

[0067] Overload protection state: 1.0s high level signal and 2.5s low level signal that cyclically appear;

[0068] PWM signal reception abnormal state: continuous high level signal.

[0069] With this protocol, the host computer can acquire the operating state of the rotor assembly by acquiring the level change signal.

[0070] It should be noted that the high level of the PWM signal and the level change signal is ≥0.6*input voltage, and the low level is ≤0.4*input voltage; for example, when the input voltage is 12V, the high level range should be ≥7.2V, and the low level range should be ≤4.8V.

[0071] It should be noted that the specific method for determining whether to enter the idling protection state is:

[0072] In one clock cycle, if the ratio of the square of the rotational speed n of the rotor assembly to the driving current I output by the driving chip to the stator assembly is n 2If I is greater than a preset first threshold value, then further determine whether the rotation speed n of the rotor assembly is greater than a preset second threshold value, if not, then increase the idle protection count value by 1, if yes, then decrease the idle protection count value by 1;

[0073] If the driving current I outputted by the driving chip to the stator assembly is less than a preset third threshold value in a clock cycle, then increase the idle protection count value by 1;

[0074] If the rotation speed n of the rotor assembly is greater than a preset fourth threshold value in a clock cycle, then increase the idle protection count value by 1;

[0075] If the above conditions are not met in a clock cycle, then decrease the idle protection count value by 1;

[0076] When the idle protection count value is greater than a preset fifth threshold value, then trigger the idle protection state.

[0077] Further specifically, the first threshold value is 10000 (the first threshold value is a ratio, so no physical unit is needed), the second threshold value is 1800 rpm, the third threshold value is 0.4 A, the fourth threshold value is 6500 rpm, and the fifth threshold value is 2500 (the fifth threshold value is a count value in a register, so it has no physical unit).

[0078] The rotor assembly during idling is prone to wear due to lack of lubrication of the liquid medium, and is prone to heat accumulation due to lack of heat conduction of the liquid medium, so the driving chip needs to start the idle protection mode and enter the idle protection state, such as stopping outputting after a delay.

[0079] It should be noted that the specific method for determining whether to enter the stall protection state is as follows:

[0080] If the ratio n:I of the rotation speed n of the rotor assembly and the driving current I outputted by the driving chip to the stator assembly is less than a preset sixth threshold value in a clock cycle, then increase the stall protection count value by 1;

[0081] If the rotation speed n of the rotor assembly is less than a preset seventh threshold value in a clock cycle, then increase the stall protection count value by 1;

[0082] If the rotation speed n of the rotor assembly is greater than a preset eighth threshold value in a clock cycle, then increase the stall protection count value by 1;

[0083] When the stall protection count value is greater than a preset ninth threshold value, then trigger the stall protection state.

[0084] Further specifically, the sixth threshold value is 55 (the sixth threshold value is a ratio, so no physical unit is used), the seventh threshold value is 300 rpm, the eighth threshold value is 10000 rpm, and the ninth threshold value is 1000 (the ninth threshold value is a count value in a register, so it has no physical unit).

[0085] Stall is harmful to the driving chip, the stator assembly, and the rotor assembly, so the driving chip needs to start a stall protection mode and enter a stall protection state, for example, stop outputting after a delay.

[0086] It should be noted that the over-temperature protection state is specifically:

[0087] The temperature of the driving chip is collected by a temperature collection module built in the driving chip.

[0088] When the temperature of the driving chip is higher than 135℃, the speed n of the rotor assembly is limited to 80% of the maximum speed n max .

[0089] When the temperature of the driving chip is higher than 145℃, the speed n of the rotor assembly is limited to 60% of the maximum speed n max .

[0090] When the temperature of the driving chip is higher than 165℃, the driving chip stops outputting the driving current I, and the rotor assembly does not rotate.

[0091] Over-temperature is harmful to the driving chip, the stator assembly, and the rotor assembly, so the driving chip needs to start an over-temperature protection mode and enter an over-temperature protection state.

[0092] In this embodiment, the speed n of the rotor assembly is obtained by the driving chip collecting the bus currents of each phase of the rotor assembly, calculating three-phase currents, and operating through a built-in flux observer module.

[0093] The overload protection state is that the driving voltage U and / or the driving current I output by the driving chip are greater than a preset threshold value, that is, the overload protection mode is started and the overload protection state is entered, for example, stop outputting after a delay; wherein the driving voltage U and the driving current I output by the driving chip are detected through the built-in module of the driving chip.

[0094] The two-wire electronic water pump control method of this embodiment can linearly control the driving current I and the speed n of the rotor assembly by adjusting the duty cycle D of the PWM signal, can feed back the running state of the rotor assembly through the level change signal, and can linearly control the running of the electronic water pump in the form of PWM signal duty cycle through a single external interface with a certain protocol, and can feed back the running state of the electronic water pump, thereby reducing the secondary development cost of the electronic water pump.

[0095] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A two-wire-in-one electronic water pump control method applied to an electronic water pump; characterized in that, The electronic water pump at least comprises a driving chip, a stator assembly and a rotor assembly; The driving chip is electrically connected with the stator assembly in phase polarity, so that the driving chip can drive the stator assembly to generate a rotating magnetic field, and the rotor assembly is driven to rotate by magnetic coupling of the rotating magnetic field, and the driving chip at least leads a signal input / output interface; The method comprises: The host computer outputs a PWM signal to the driving chip through the signal input / output interface, and defines a duty cycle D of the PWM signal, so that: When 0% < D < 8%, the driving chip outputs maximum driving current I to the stator assembly max , and the rotor assembly rotates at maximum rotating speed n max . When 8%≤D<13%, the driving chip does not output a driving current I to the stator assembly, and the rotor assembly does not rotate; when 13% < D < 93%, the driving chip outputs driving current I to the stator assembly, the rotor assembly rotates, and as the duty cycle D of the PWM signal linearly increases, the driving chip starts from minimum driving current I min linearly increases until reaching maximum driving current I max , the rotor assembly starts from minimum rotating speed n min linearly increases until reaching maximum rotating speed n max ; When 93% < D ≤ 100%, the driving chip outputs maximum driving current I to the stator assembly max , and the rotor assembly rotates at maximum rotating speed n max . The driving chip outputs a level change signal to the host computer through the signal input / output interface to indicate the running state of the rotor assembly; The running state of the rotor assembly specifically comprises: a normal running state, an idling protection state, a locked-rotor protection state, an over-temperature protection state, an overload protection state and a PWM signal reception abnormal state; The specific method for determining whether to enter the idling protection state is: In one clock cycle, if the ratio of the square of the rotation speed n of the rotor assembly and the driving current I output by the driving chip to the stator assembly is n 2 :I is greater than the preset first threshold value, then further determine whether the rotation speed n of the rotor assembly is greater than the preset second threshold value, if not, the idle protection count value is +1, if yes, the idle protection count value is -1; In one clock cycle, if the driving current I output by the driving chip to the stator assembly is less than a preset third threshold value, the idling protection count value is increased by 1; In one clock cycle, if the rotating speed n of the rotor assembly is greater than a preset fourth threshold value, the idling protection count value is increased by 1; In one clock cycle, if the above conditions are not met, the idling protection count value is decreased by 1; When the idling protection count value is greater than a preset fifth threshold value, the idling protection state is triggered; The first threshold value is 10000, the second threshold value is 1800 rpm, the third threshold value is 0.4 A, the fourth threshold value is 6500 rpm, and the fifth threshold value is 2500; The specific method for determining whether to enter the locked-rotor protection state is: In one clock cycle, if the ratio n:I of the rotating speed n of the rotor assembly to the driving current I output by the driving chip to the stator assembly is less than a preset sixth threshold value, the locked-rotor protection count value is increased by 1; In one clock cycle, if the rotating speed n of the rotor assembly is less than a preset seventh threshold value, the locked-rotor protection count value is increased by 1; In one clock cycle, if the rotating speed n of the rotor assembly is greater than a preset eighth threshold value, the locked-rotor protection count value is increased by 1; When the locked-rotor protection count value is greater than a preset ninth threshold value, the locked-rotor protection state is triggered; The sixth threshold value is 55, the seventh threshold value is 300 rpm, the eighth threshold value is 10000 rpm, and the ninth threshold value is 1000.

2. The two-in-one electronic water pump control method according to claim 1, wherein The level change signal specifically comprises: a continuous high-level signal, a continuous low-level signal, and a high-level signal and a low-level signal that cyclically appear and have the same or different continuous durations.

3. The two-in-one electronic water pump control method according to claim 1, wherein The level change signal specifically is: Normal running state: 4.5s high-level signal and 0.5s low-level signal cyclically appear; Idling protection state: 1.0s high-level signal and 1.0s low-level signal cyclically appear; Locked-rotor protection state: 0.5s high-level signal and 0.5s low-level signal cyclically appear. Stall protection state: 1.0s high level signal and 1.5s low level signal appear cyclically; Over-temperature protection state: 1.0s high level signal and 2.0s low level signal appear cyclically; Overload protection state: 1.0s high level signal and 2.5s low level signal appear cyclically; PWM signal receiving abnormal state: continuous high level signal.

4. The two-in-one electronic water pump control method according to claim 1, wherein The over-temperature protection state specifically comprises: collecting the temperature of the driving chip through a temperature collection module built in the driving chip; when the temperature of the drive chip is higher than 135℃, the rotating speed n of the rotor assembly is limited to the maximum rotating speed n max 80% of the maximum rotating speed n. when the temperature of the drive chip is higher than 145℃, the rotating speed n of the rotor assembly is limited to the maximum rotating speed n max 60%; when the temperature of the driving chip is higher than 165 DEG C, the driving chip stops outputting the driving current I, and the rotor assembly does not rotate.

5. The two-in-one electronic water pump control method according to claim 1, wherein The high level of the PWM signal and the level change signal is greater than or equal to 0.6 times the input voltage, and the low level is less than or equal to 0.4 times the input voltage.

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