Electromechanical parameter detection method of direct current permanent magnet brush motor and related assembly

Abstract

The invention discloses an electromechanical parameter detection method of a direct-current permanent magnet brush motor and a related component, which are applied to the technical field of motors, and comprise the following steps: when the motor is in a first state, determining a motor voltage, a motor current and a no-load rotating speed in the first state; after the motor is switched from the first state to the second state, motor voltage and motor current at the initial moment of the second state are determined; the first state indicates that the motor is connected with a direct-current power supply and runs to a stable state without load; the second state indicates that the motor is separated from the direct-current power supply and connected with the load resistor after separation, or freely decelerates after separation; and determining the internal resistance of the motor under the condition of no-load rotating speed based on the motor voltage and the motor current in the first state and at the initial moment of the second state. According to the scheme, electromechanical parameter detection of the motor can be effectively achieved, and the detection accuracy is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of electric motors, and particularly to a method for detecting electromechanical parameters of a DC permanent magnet brushed motor and related components. Background Art

[0002] The resistance of a DC permanent magnet brushed motor (hereinafter referred to as the motor) includes the winding resistance of the armature coil, the lead resistance from the terminal to the carbon brush, the carbon brush resistance, and the contact resistance between the carbon brush and the commutator, which constitute the internal resistance of the motor. Due to the influence of the contact resistance, the internal resistance will change with the rotational speed. The internal resistance and the back electromotive force constant of the motor have an important influence on the operating characteristics of the motor. Accurately measuring their parameter values provides basic data for correctly obtaining the electromechanical characteristics of the motor.

[0003] Currently, one of the methods for detecting the internal resistance of a motor is to calculate the internal resistance from the voltage and current at the moment of motor startup (stall). However, since the measured internal resistance is different when the commutator of the motor stops at different positions relative to the carbon brush, the test data has poor repeatability and large errors. Moreover, due to the existence of the armature inductance, there will also be a large deviation between the internal resistance calculated from the voltage and current at the startup moment and the actual internal resistance.

[0004] In summary, how to effectively implement the detection of the electromechanical parameters of the motor and ensure the accuracy of the detection is a technical problem that those skilled in the art urgently need to solve at present. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for detecting electromechanical parameters of a DC permanent magnet brushed motor and related components to effectively implement the detection of the electromechanical parameters of the motor and ensure the accuracy of the detection.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a method for detecting electromechanical parameters of a DC permanent magnet brushed motor, including:

[0008] When the motor is in a first state, determining the motor voltage, motor current, and no-load speed in the first state;

[0009] After the motor switches from the first state to the second state, determining the motor voltage and motor current at the initial moment of the second state;

[0010] Wherein, the first state means that the motor is connected to a DC power supply and runs no-load to a stable state; the second state means that the motor disconnects from the DC power supply and connects a load resistor after disconnection, or freely decelerates after disconnection.

[0011] Based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force in the first state is consistent with the motor back electromotive force at the initial moment of the second state, the internal resistance of the motor under the no-load speed condition is determined.

[0012] In one embodiment, it further includes:

[0013] Based on the motor voltage, motor current, no-load speed in the first state, and the determined internal resistance of the motor under the no-load speed condition, the motor back electromotive force constant is determined.

[0014] In one embodiment, based on the motor voltage, motor current, no-load speed in the first state, and the determined internal resistance of the motor under the no-load speed condition, determining the motor back electromotive force constant includes:

[0015] Based on the motor voltage, motor current, no-load speed in the first state, and the determined internal resistance of the motor under the no-load speed condition, through the calculation method, the motor back electromotive force constant K is determined e ;

[0016] wherein, V1 is the motor voltage in the first state; is the motor current in the first state; n0 is the no-load speed in the first state; r1 is the determined internal resistance of the motor under the no-load speed n0; K e is the determined motor back electromotive force constant.

[0017] In one embodiment, based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force in the first state is consistent with the motor back electromotive force at the initial moment of the second state, determining the internal resistance of the motor under the no-load speed condition includes:

[0018] Based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force E0 in the first state is consistent with the motor back electromotive force E0 at the initial moment of the second state, through the calculation method, the internal resistance r1 of the motor under the no-load speed n0 is determined;

[0019] wherein, V1 is the motor voltage in the first state; I0 is the motor current in the first state; n0 is the no-load speed in the first state; r1 is the internal resistance of the motor at the no-load speed n0; E0 is the back electromotive force value of the motor at the no-load speed n0; V S V is the motor voltage at the initial moment of the second state; I is the motor current at the initial moment of the second state.

[0020] In one embodiment, after the motor switches from the first state to the second state, determining the motor voltage at the initial moment of the second state includes:

[0021] Dividing the discharge period into X sampling intervals; wherein, the discharge period represents the period from when the motor switches from the first state to the second state until the motor stops rotating; X is a positive integer not less than 2;

[0022] For each sampling interval, taking the integral mean of the motor voltage within the sampling interval as the motor voltage at the midpoint moment of the sampling interval;

[0023] Based on the motor voltages at the midpoint moments of the X sampling intervals respectively, obtaining an (X - 1)-order curve function of the motor voltage varying with time during the discharge period;

[0024] Based on the (X - 1)-order curve function of the motor voltage varying with time during the discharge period, obtaining the motor voltage at the initial moment of the second state.

[0025] In one embodiment, when the second state is specifically that the motor disconnects from the DC power supply and freely decelerates after disconnection, the determined motor current at the initial moment of the second state is 0;

[0026] When the second state is specifically that the motor disconnects from the DC power supply and connects a load resistor after disconnection, after the motor switches from the first state to the second state, determining the motor current at the initial moment of the second state includes:

[0027] Dividing the discharge period into X sampling intervals; wherein, the discharge period represents the period from when the motor switches from the first state to the second state until the motor stops rotating; X is a positive integer not less than 2;

[0028] For each sampling interval, taking the integral mean of the motor current within the sampling interval as the motor current at the midpoint moment of the sampling interval;

[0029] Based on the motor current at the mid-time of each of the X sampling intervals, obtain the (X - 1)-order curve function of the motor current varying with time during the discharge period;

[0030] Based on the (X - 1)-order curve function of the motor current varying with time during the discharge period, obtain the motor current at the initial moment of the second state.

[0031] In one implementation, it further includes:

[0032] Through N detections, determine the corresponding motor internal resistance under different no-load speeds; where N is a positive integer not less than 2.

[0033] Based on the determined corresponding motor internal resistance under different no-load speeds, obtain the (N - 1)-order curve function of the motor internal resistance varying with speed.

[0034] In a second aspect, the present invention provides an electromechanical parameter detection system for a DC permanent magnet brushed motor, including:

[0035] A first state detection module, configured to determine the motor voltage, motor current, and no-load speed in the first state when the motor is in the first state;

[0036] A second state detection module, configured to determine the motor voltage and motor current at the initial moment of the second state after the motor switches from the first state to the second state;

[0037] Wherein, the first state means that the motor is connected to a DC power supply and runs no-load to a stable state; the second state means that the motor disconnects from the DC power supply and connects a load resistor after disconnection, or freely decelerates after disconnection;

[0038] A motor internal resistance determination module, configured to determine the motor internal resistance under the no-load speed based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force in the first state is consistent with the motor back electromotive force at the initial moment of the second state.

[0039] In a third aspect, the present invention provides an electromechanical parameter detection device for a DC permanent magnet brushed motor, including:

[0040] A memory, configured to store a computer program;

[0041] A processor, configured to execute the computer program to implement the steps of the electromechanical parameter detection method for the DC permanent magnet brushed motor as described above.

[0042] In a fourth aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for detecting the electromechanical parameters of the DC permanent magnet brushed motor as described above are implemented.

[0043] Applying the technical solution provided by the embodiment of the present invention, when the motor is in the first state, the motor voltage, motor current, and no-load speed in the first state will be determined. The first state means that the motor is connected to the DC power supply and runs without load until it reaches a stable state. Therefore, it can be seen that the motor voltage, motor current, and no-load speed in the first state obtained by the solution of the present application are all relatively accurate values. The motor voltage and motor current in the first state are also the no-load voltage and no-load current. And from the electromechanical equation of the motor running without load, it can be known that the magnitude of the no-load current depends on the no-load voltage, the internal resistance of the motor, and the back electromotive force of the motor at this time. After that, the motor switches from the first state to the second state, and it is necessary to determine the motor voltage and motor current at the initial moment of the second state. The second state means that the motor is disconnected from the DC power supply and a load resistor is connected after disconnection, or it freely decelerates after disconnection. Considering that the back electromotive force of the motor does not change suddenly during the switching instant, based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, according to the principle that the back electromotive force of the motor in the first state is consistent with the back electromotive force of the motor at the initial moment of the second state, the internal resistance of the motor under the no-load speed condition can be determined. It can be seen that in the solution of the present application, the internal resistance is not calculated by using the voltage and current in the starting moment (stall) state of the motor as in the traditional solution. Therefore, there will be no situation of poor repeatability and large error. That is to say, in the solution of the present application, the accuracy of the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state can be effectively guaranteed, and thus the accuracy of the internal resistance of the motor under the no-load speed condition determined can also be effectively guaranteed.

[0044] In summary, the solution of the present application can effectively implement the detection of the electromechanical parameters of the motor and ensure the accuracy of the detection. Description of the Drawings

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0046] Figure 1It is the implementation flowchart of the electromechanical parameter detection method for the DC permanent magnet brushed motor provided by a specific embodiment of the present invention;

[0047] Figure 2 It is the schematic diagram of the detection circuit used for detecting the electromechanical parameters of the motor in a specific embodiment of the present invention;

[0048] Figure 3 It is the equivalent circuit diagram of the motor in the first state in a specific embodiment of the present invention;

[0049] Figure 4 It is the equivalent circuit diagram of the motor in the second state in a specific embodiment of the present invention;

[0050] Figure 5 It is the schematic diagram of the ideal waveforms of the motor voltage and the motor current when the motor is disconnected from the DC power supply and then the load resistance is connected in a specific embodiment of the present invention;

[0051] Figure 6 It is the schematic diagram of the actual waveforms of the motor voltage and the motor current when the motor is disconnected from the DC power supply and then the load resistance is connected in a specific embodiment of the present invention;

[0052] Figure 7 It is the schematic diagram of the ideal waveforms of the motor voltage and the motor current when the motor is disconnected from the DC power supply and then freely decelerates in a specific embodiment of the present invention;

[0053] Figure 8 It is the schematic diagram of the actual waveforms of the motor voltage and the motor current when the motor is disconnected from the DC power supply and then freely decelerates in a specific embodiment of the present invention;

[0054] Figure 9 It is the schematic diagram of the actual waveforms of the motor voltage and the motor current when the motor is disconnected from the DC power supply and then the load resistance is connected in another specific embodiment of the present invention;

[0055] Figure 10 It is the schematic diagram of the quadratic curve function of the motor internal resistance changing with the rotational speed determined in a specific embodiment of the present invention.

[0056] Figure 11 It is the schematic diagram of the structure of the electromechanical parameter detection system of the motor provided by a specific embodiment of the present invention;

[0057] Figure 12 It is the schematic diagram of the structure of the electromechanical parameter detection device of the motor provided by a specific embodiment of the present invention. Specific embodiment

[0058] The core of the present invention is to provide a method, system, device and storage medium for detecting the electromechanical parameters of a DC permanent magnet brushed motor, which can effectively realize the detection of the electromechanical parameters of the motor and ensure the accuracy of the detection.

[0059] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0060] Please refer to Figure 1 , Figure 1 is the flowchart of the implementation of the method for detecting the electromechanical parameters of a DC permanent magnet brushed motor provided by a specific embodiment of the present invention. The method for detecting the electromechanical parameters of the DC permanent magnet brushed motor may include the following steps:

[0061] Step S101: When the motor is in the first state, determine the motor voltage, motor current and no-load speed in the first state.

[0062] The motor described in the solution of the present application may be a DC permanent magnet brushed motor. Of course, in other specific scenarios, it may be set as other types of motors according to actual needs. That is, for other types of motors, the principle of the present application can be selected and used to realize the detection of electromechanical parameters according to actual needs, which does not affect the implementation of the present application.

[0063] The first state means that the motor is connected to the DC power supply and runs without load until it reaches a stable state. Therefore, in actual applications, the motor can be connected to the DC power supply, so that the motor runs without load. After waiting for the operation to be stable, the motor voltage, motor current and no-load speed can be detected. It can be understood that the motor voltage and motor current detected at this time are also the no-load voltage and no-load current of the motor.

[0064] For easy understanding, please refer to Figure 2 and Figure 3 , Figure 2 is a schematic diagram of the detection circuit used for detecting the electromechanical parameters of the motor in a specific embodiment, Figure 3 is the equivalent circuit diagram when the motor is in the first state. Figure 2 and Figure 3 In, the DC voltage output by the DC power supply is denoted as Ep. The motor can be connected to the DC power supply through the first switch K1. Figure 2 In, V and A shown respectively represent a voltmeter and an ammeter for detecting the motor voltage and motor current respectively, and M represents the motor.

[0065] After the motor is connected to the DC power supply Ep and runs no-load to a stable state, the motor voltage, motor current, and no-load speed can all be obtained through detection, and are respectively denoted as the motor voltage V1 in the first state, the motor current in the first state and the no-load speed n0 in the first state. Of course, from Figure 3 it can also be seen that the motor voltage V1 at this time is equal to Ep, that is, V1 = Ep. Therefore, in practical applications, since the voltage magnitude output by the DC power supply Ep is pre-given, the motor voltage V1 in the first state can be directly given without detection, that is, directly use Ep as the motor voltage V1 in the first state.

[0066] The motor current and no-load speed can usually be detected based on methods such as a speed sensor.

[0067] In addition, it can be known from the electromechanical equation of the motor running no-load that the magnitude of the no-load current depends on the no-load voltage, the internal resistance of the motor, and the back electromotive force of the motor at this time. In the first state, the electromechanical equation of the motor running no-load can be expressed as . E0 is the value of the back electromotive force of the motor at the no-load speed n0. In Figure 3 the back electromotive force value E0 of the motor and the internal resistance r1 of the motor at the no-load speed n0 are also shown. And through it can be seen that since both E0 and r1 are unknowns, only based on the motor voltage V1 and motor current in the first state it is impossible to calculate the internal resistance r1 of the motor.

[0068] Step S102: After the motor switches from the first state to the second state, determine the motor voltage and motor current at the initial moment of the second state.

[0069] After determining the motor voltage, motor current, and no-load speed in the first state, the motor needs to be switched from the first state to the second state. In the solution of this application, the second state means that the motor is disconnected from the DC power supply and then connected to a load resistor after disconnection, or freely decelerates after disconnection.

[0070] First, take the example of connecting a load resistor after disconnection for illustration. From Figure 2 it can be known that by controlling the first switch K1 and the second switch K2, the motor can be disconnected from the DC power supply Ep and connected to the load resistor R. The equivalent circuit diagram at this time can be referred to Figure 4 .

[0071] At the initial moment of the second state, that is, at the instant of switching, the motor speed is equal to the no-load speed n0 in the first state, and the back electromotive force value of the motor at this instant does not change suddenly. At this time, the electromechanical equation of the motor operation can be expressed as , V S and are the motor voltage and motor current at the initial moment of the second state, which can be directly detected or indirectly detected as described in the embodiments of the present invention later.

[0072] If it is free deceleration after disconnection, that is, after disconnection, the load resistance is not connected, but free deceleration from the no-load speed to stop. From Figure 2 it can be seen that, similarly, through the control of the first switch K1 and the second switch K2, the motor does not connect the load resistance after disconnecting from the DC power supply Ep. At this time, the electromechanical equation of the motor operation can also be expressed as , but it can be understood that since the motor does not connect the load resistance after disconnecting from the DC power supply (or can be regarded as connecting a load resistance with an infinite resistance value), after entering the second state, the motor current is equal to 0.

[0073] Step S103: Based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the back electromotive force of the motor in the first state is consistent with the back electromotive force of the motor at the initial moment of the second state, determine the internal resistance of the motor at the no-load speed.

[0074] After obtaining the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, as described above, at the instant of state switching, the motor speed is equal to the no-load speed n0 in the first state, and the back electromotive force value of the motor at this instant does not change suddenly. Therefore, in accordance with the principle that the back electromotive force of the motor in the first state is consistent with the back electromotive force of the motor at the initial moment of the second state, the internal resistance of the motor at the no-load speed can be determined.

[0075] In a specific embodiment of the present invention, step S103 may specifically include:

[0076] Based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the back electromotive force E0 of the motor in the first state is consistent with the back electromotive force E0 of the motor at the initial moment of the second state, through the calculation method, determine the internal resistance r1 of the motor at the no-load speed n0;

[0077] Among them, V1 is the motor voltage in the first state; is the motor current in the first state; n0 is the no-load speed in the first state; r1 is the internal resistance of the motor under the no-load speed n0; E0 is the back electromotive force value of the motor under the no-load speed n0; V S is the motor voltage at the initial moment of the second state; is the motor current at the initial moment of the second state.

[0078] In this embodiment, it is considered that the motor voltage V1 and the motor current in the first state are detected , so in the first state, the electromechanical equation of the motor running without load can be expressed as . And at the moment when the motor is switched from the first state to the second state, the motor voltage V at this moment is obtained S and the motor current After that, since the speed and the back electromotive force of the motor do not change suddenly, the electromechanical equation of the motor running at this time can be expressed as .

[0079] In this embodiment, it is possible to combine and to obtain , that is, the internal resistance r1 of the motor under the no-load speed n0 can be determined by calculation method.

[0080] It can be seen that in this embodiment, the internal resistance r1 of the motor is calculated by , which is simple and convenient in calculation, and as long as the motor voltage V1 and the motor current in the first state can be accurately determined , and the motor voltage V in the second state S and the motor current , the internal resistance r1 of the motor under the no-load speed n0 can be accurately obtained. In addition, in the first state, the motor runs stably in the no-load state, so V1, and n0 can all be directly measured by relevant detection circuits / sensors, and the accuracy is relatively high. Of course, as described above, V1 can also be directly given in practical applications.

[0081] In a specific embodiment of the present invention, it may further include:

[0082] Based on the motor voltage, motor current, no-load speed in the first state, and the determined internal resistance of the motor under the no-load speed, determine the back electromotive force constant of the motor.

[0083] This implementation mode takes into account that the back electromotive force constant of the motor represents the value of the back electromotive force generated per unit speed of the motor, which also has an important impact on the operating characteristics of the motor. Therefore, this implementation mode will also calculate the back electromotive force constant of the motor based on the motor voltage, motor current, no-load speed in the first state, and the determined internal resistance of the motor under no-load speed conditions.

[0084] There are various specific implementation methods for determining the back electromotive force constant of the motor. In a specific implementation mode of the present invention, based on the motor voltage, motor current, no-load speed in the first state, and the determined internal resistance of the motor under no-load speed conditions, determining the back electromotive force constant of the motor may specifically include:

[0085] Based on the motor voltage, motor current, no-load speed in the first state, and the determined internal resistance of the motor under no-load speed conditions, through the calculation method, determine the back electromotive force constant K of the motor e ;

[0086] Among them, V1 is the motor voltage in the first state; is the motor current in the first state; n0 is the no-load speed in the first state; r1 is the determined internal resistance of the motor under the no-load speed n0; E0 is the back electromotive force value of the motor under the no-load speed n0; K e is the determined back electromotive force constant of the motor.

[0087] This implementation mode takes into account that when the motor operates under no-load, the back electromotive force constant of the motor , the back electromotive force E0 of the motor is an unknown quantity, and as described above, in the first state, the electromechanical equation of the motor operating under no-load can be expressed as , so it can be seen that after determining the internal resistance r1 of the motor under the no-load speed n0, based on the motor voltage, motor current, no-load speed in the first state, and the determined internal resistance r1 of the motor, through the calculation method, conveniently determine the back electromotive force constant K of the motor e . In addition, it can be understood that in the first state, the motor operates stably under no-load, so the motor voltage V1 in the first state, the motor current in the first state, and the no-load speed n0 in the first state can all be accurately measured. When accurately obtaining the internal resistance r1 of the motor under the no-load speed n0, this implementation mode can accurately obtain the back electromotive force constant K of the motor e .

[0088] In a specific embodiment of the present invention, after the motor switches from the first state to the second state, determining the motor voltage at the initial moment of the second state includes:

[0089] Dividing the discharge period into X sampling intervals; wherein, the discharge period refers to the period from when the motor switches from the first state to the second state until the motor stops rotating; X is a positive integer not less than 2;

[0090] For each sampling interval, taking the integral mean value of the motor voltage within the sampling interval as the motor voltage at the midpoint moment of the sampling interval;

[0091] Based on the motor voltages at the midpoint moments of the X sampling intervals respectively, obtaining an (X - 1)-order curve function of the motor voltage varying with time within the discharge period;

[0092] Based on the (X - 1)-order curve function of the motor voltage varying with time within the discharge period, obtaining the motor voltage at the initial moment of the second state.

[0093] To determine the motor voltage Vs at the initial moment of the second state, a simple implementation is to directly detect the motor voltage by means of a voltmeter, etc. at the initial moment of the second state, that is, the detection result at the initial moment of the second state can be directly used as the motor voltage Vs at the initial moment of the second state.

[0094] This embodiment further considers that at the moment when the motor switches from the first state to the second state, due to the influence of factors such as carbon brush commutation and coil inductance, the actual working parameter waveform has ripples, especially at the moment when the first state switches to the second state, irregular spike noise is likely to occur. Refer to Figure 5 , Figure 6 , Figure 7 and Figure 8 , Figure 5 which are schematic diagrams of the ideal waveforms of the motor voltage and the motor current when the motor is disconnected from the DC power supply and then connected to the load resistance, Figure 6 while Figure 7 is a schematic diagram of the actual waveforms of the motor voltage and the motor current in this case. Figure 8 is a schematic diagram of the ideal waveforms of the motor voltage and the motor current when the motor freely decelerates after being disconnected from the DC power supply, Figure 5 while Figure 6 is a schematic diagram of the actual waveforms of the motor voltage and the motor current in this case. Figure 7 and Figure 8 where the moment ts is the moment when the motor switches from the first state to the second state, that is, before the moment ts, the motor is in the first state, from Figure 6 andFigure 8 It can be seen that when switching from the first state to the second state, regardless of whether the load resistance is connected or the motor decelerates freely after the motor is disconnected from the DC power supply, a large voltage fluctuation occurs in the motor voltage at the moment of switching and for a short period of time afterwards. Moreover, from Figure 6 it can be seen that when the load resistance is connected after the motor is disconnected from the DC power supply, a large current fluctuation also occurs in the motor current at the moment of switching and for a short period of time afterwards.

[0095] In this embodiment, instead of directly detecting the motor voltage at the moment of switching from the first state to the second state and using the detection result as the motor voltage at that moment, after the motor switches from the first state to the second state, X sampling intervals are divided from the discharge period, and then the motor voltage at the switching moment is obtained by calculation.

[0096] The discharge period described in this embodiment refers to the period from when the motor switches from the first state to the second state until the motor stops rotating, that is, the discharge period starts after entering the second state. Dividing X sampling intervals from the discharge period, the specific division method can be set and adjusted according to actual needs. For example, in practical applications, considering that the motor voltage fluctuates greatly at the moment of just switching to the second state and for a short period of time afterwards, the starting moment of the first sampling interval can be set at a moment after avoiding the peak clutter. The duration of each sampling interval can be the same, or the duration of each sampling interval can be adjusted according to needs. The value of X can also be set according to needs. And considering that after entering the second state, the change of the motor voltage approximates a quadratic curve, so X can preferably be 3. Of course, in other specific situations, the value of X can be adjusted according to needs.

[0097] For example Figure 9 is a schematic diagram of the theoretical waveforms of the motor voltage and the motor current when the load resistance is connected after the motor is disconnected from the DC power supply in a specific embodiment. In Figure 9 this example, X is set to 3, that is, 3 sampling intervals are divided from the discharge period. The first sampling interval is from Figure 9 the moment t0 in Figure 9 to the moment t1, the second sampling interval is from Figure 9 the moment t1 in

[0098] For each sampling interval, the integral mean value of the motor voltage within the sampling interval needs to be used as the motor voltage at the midpoint moment of the sampling interval. That is to say, for each sampling interval, by detecting the motor voltage, the motor voltages at different moments within the sampling interval can be obtained, and then integrated. And the motor voltage within this sampling interval is regarded as changing in a linear trend. Therefore, the integral mean value of the motor voltage within this sampling interval can be used as the motor voltage at the midpoint moment of this sampling interval.

[0099] Still taking Figure 9 as an example, for the first sampling interval, the integral mean value of the motor voltage can be expressed as . The midpoint moment of the first sampling interval is denoted as t 01 , and the motor voltage at this moment is denoted as V 01 , then V 01 = . It can be seen that the motor voltage V 01 is not obtained by detection at the moment of t 01 , but is obtained by integrating and averaging all the detection results from the moment of t0 to the moment of t1, so that the obtained motor voltage V 01 has a higher accuracy and can effectively reduce interference.

[0100] In addition, it can be understood that since this implementation method requires calculating the integral mean value of the motor voltage within the sampling interval, in order to ensure accuracy, it is usually possible to detect periodically and set a relatively high detection frequency, so that the motor voltages at multiple different moments within the sampling interval can be obtained, thereby ensuring the accuracy of the calculation of the integral mean value of the motor voltage within this sampling interval.

[0101] Similarly, for Figure 9 's second sampling interval, the integral mean value of the motor voltage can be expressed as . The midpoint moment of the second sampling interval is denoted as t 12 , and the motor voltage at this moment is denoted as V 12 , then V 12 = . The motor voltage V 12 is not obtained by detection at the moment of t 12 , but is obtained by integrating and averaging all the detection results from the moment of t1 to the moment of t2, so that the obtained motor voltage V 12 has a higher accuracy and can effectively reduce interference.

[0102] Similarly, for Figure 9 's third sampling interval, the integral mean value of the motor voltage can be expressed as The midpoint time of the third sampling interval is denoted as t 23 , and the motor voltage at this time is denoted as V 23 , then V 23 = . The motor voltage V 23 is not obtained by detection at time t 23 , but by integrating and averaging all the detection results from time t2 to time t3, so that the obtained motor voltage V 23 has a higher accuracy and can effectively reduce interference.

[0103] The variation of the motor voltage with time during the discharge period can be regarded as a quadratic curve function. Therefore, after obtaining the motor voltages at the midpoint times of each of the X sampling intervals, the quadratic curve function of the motor voltage varying with time during the discharge period can be obtained based on the motor voltages at the midpoint times of each of the X sampling intervals. For example, the quadratic curve function of the motor voltage varying with time during the discharge period is denoted as , where Va, Vb, and Vc in this formula are all unknown parameters. In the above Figure 9 example, after obtaining the motor voltages at the midpoint times of each of the 3 sampling intervals, Va, Vb, and Vc can be determined accordingly, which can be expressed as:

[0104] , and by determining Va, Vb, and Vc, that is, determining the quadratic curve function of the motor voltage varying with time during the discharge period.

[0105] In addition, in practical applications, when the value of X is set to more than 3, the curve function of the corresponding order of the motor voltage varying with time during the discharge period can also be obtained by calculation based on the motor voltages at the midpoint times of each of the X sampling intervals. For example, when X is set to 4, a cubic curve function of the motor voltage varying with time during the discharge period can be obtained. Of course, as described above, the change of the motor voltage is close to a quadratic curve, so X is preferably 3.

[0106] In this example, after obtaining the quadratic curve function of the motor voltage varying with time during the discharge period, substituting the initial time ts of the second state into this quadratic curve function can obtain the motor voltage Vs at the initial time of the second state.

[0107] In this implementation manner, since the motor voltages at the midpoint times of each sampling interval can be obtained relatively accurately, the quadratic curve function of the motor voltage varying with time during the discharge period determined accordingly is also relatively accurate, so that the motor voltage Vs at the initial time of the second state obtained based on this quadratic curve function is a relatively accurate value.

[0108] In addition, it should be noted that, as described above with Figure 9 as an example in detail, Figure 9 in the embodiment of , after the motor is disconnected from the DC power supply, the load resistance is connected. If the embodiment of the motor freely decelerating after being disconnected from the DC power supply is adopted, the motor voltage Vs at the initial moment of the second state can also be obtained according to the principle of this embodiment, and the obtained motor voltage Vs at the initial moment of the second state is a relatively accurate value.

[0109] In a specific embodiment of the present invention, when the second state is specifically that the motor is disconnected from the DC power supply and freely decelerates after disconnection, the determined motor current at the initial moment of the second state is 0.

[0110] When the second state is specifically that the motor is disconnected from the DC power supply and the load resistance is connected after disconnection, after the motor switches from the first state to the second state, determining the motor current at the initial moment of the second state includes:

[0111] Dividing the discharge period into X sampling intervals; wherein, the discharge period refers to the period from when the motor switches from the first state to the second state until the motor stops rotating;

[0112] For each sampling interval, taking the integral mean value of the motor current within the sampling interval as the motor current at the midpoint moment of the sampling interval;

[0113] Based on the motor currents at the midpoint moments of the X sampling intervals respectively, obtaining an (X - 1) - order curve function of the motor current varying with time within the discharge period;

[0114] Based on the (X - 1) - order curve function of the motor current varying with time within the discharge period, obtaining the motor current at the initial moment of the second state.

[0115] This embodiment takes into account that if the embodiment of the motor freely decelerating after being disconnected from the DC power supply is adopted when the motor switches from the first state to the second state, then Figure 7 it can be known that after entering the second state, the motor current is equal to 0, that is, the motor current at the initial moment of the second state can be directly obtained is 0, and there is no need to perform detection or calculation.

[0116] If the embodiment of the motor being disconnected from the DC power supply and the load resistance being connected after disconnection is adopted, reference can be made to Figure 9, similar to the motor voltage, at the moment when the motor switches from the first state to the second state, due to factors such as carbon brush commutation and armature inductance, the waveform of the actual working parameters has ripples. Especially at the moment when the first state switches to the second state, irregular spike noise is likely to occur. Therefore Figure 9 in it, at the moment when the motor switches from the first state to the second state and within a short period of time afterwards, both the motor voltage and the motor current show significant fluctuations.

[0117] In response to this, in this implementation manner, the detection of the motor current is not directly carried out at the moment when the first state switches to the second state, but after the motor switches from the first state to the second state, X sampling intervals are divided from the discharge period. As described above, in Figure 9 the example of, 3 sampling intervals are set.

[0118] For each sampling interval, the integral mean value of the motor current within the sampling interval needs to be used as the motor current at the midpoint moment of the sampling interval. That is to say, for each sampling interval, through the detection of the motor current, the motor currents at different moments within the sampling interval can be obtained, and then integrated. And the motor current in this sampling interval is regarded as changing in a linear trend. Therefore, the integral mean value of the motor current in this sampling interval can be used as the motor current at the midpoint moment of this sampling interval.

[0119] It should also be noted that the sampling intervals of the motor current and the motor voltage do not affect each other. That is to say, for the motor voltage, X sampling intervals can be set for it according to needs. For the motor current, X sampling intervals can also be set for it according to needs. The number of sampling intervals and the start and end moments of each sampling interval for the two can be the same or different, and can be set according to needs. Of course, in actual applications, for the convenience of calculation and setting, if the implementation manner of connecting the load resistance after the motor is disconnected from the DC power supply is adopted, the sampling intervals of the motor current and the motor voltage can usually be set to be the same, that is, the number of sampling intervals and the start and end moments of each sampling interval for the two are the same.

[0120] For Figure 9 the first sampling interval, the integral mean value of the motor current can be expressed as . The midpoint moment of the first sampling interval is denoted as t 01 , and the motor current at this moment is denoted as I 01 , then I 01 = , it can be seen that the motor current I 01 is not at t 01is not obtained by detection at a certain moment, but by integrating and averaging all the motor current detection results from time t0 to time t1, so that the obtained motor current I 01 has a relatively high accuracy and can effectively reduce interference.

[0121] Similarly, for Figure 9 the second sampling interval, the integral mean value of the motor current can be expressed as . The midpoint moment of the second sampling interval is denoted as t 12 , and the motor current at this moment is denoted as I 12 , then I 12 = . For Figure 9 the third sampling interval, the integral mean value of the motor current can be expressed as . The midpoint moment of the third sampling interval is denoted as t 23 , and the motor current at this moment is denoted as I 23 , then I 23 = . The motor current I 01 obtained by this implementation method, the motor current is denoted as I 12 and the motor current I 23 all have relatively high accuracy and can effectively reduce interference.

[0122] Similar to the motor voltage, in this implementation method, the variation of the motor current with time during the discharge period can be regarded as a quadratic curve function. Therefore, after obtaining the motor currents at the midpoint moments of the three sampling intervals respectively, the quadratic curve function of the motor current varying with time during the discharge period can be obtained accordingly. For example, the quadratic curve function of the motor current varying with time during the discharge period is denoted as , where Ia, Ib, and Ic in this formula are all unknown parameters. In the above Figure 9 example, after obtaining the motor currents at the midpoint moments of the three sampling intervals respectively, Ia, Ib, and Ic can be determined accordingly, which can be expressed as , and by determining Ia, Ib, and Ic, the quadratic curve function of the motor current varying with time during the discharge period is determined.

[0123] Similar to the motor voltage, in practical applications, when the value of X is set to other integers greater than 1, then based on the motor currents at the midpoint moments of X sampling intervals, the corresponding-order curve function of the motor current varying with time during the discharge period can be obtained. Then, by substituting the initial moment ts of the second state into the corresponding-order curve function, the motor current at the initial moment of the second state can be obtained For example, when X is set to 4, a cubic curve function of the motor current varying with time during the discharge period can be obtained. Of course, as described above, the change of the motor current with time during the discharge period approximates a quadratic curve, so X is preferably 3.

[0124] It can be seen that if the implementation mode of connecting the load resistor after the motor is disconnected from the DC power supply is adopted, in this implementation mode, since the motor current at the midpoint moment of each sampling interval can be obtained relatively accurately, the corresponding curve function of the motor current varying with time during the discharge period determined accordingly is also relatively accurate. Thus, based on the corresponding curve function, the motor current at the initial moment of the second state is a relatively accurate value.

[0125] In a specific implementation mode of the present invention, it may further include:

[0126] Through N detections, the corresponding motor internal resistance under different no-load speeds is determined; where N is a positive integer not less than 2, and the preferred value is 3.

[0127] Based on the determined corresponding motor internal resistances under different no-load speeds, a (N - 1) - order curve function of the motor internal resistance varying with the speed is obtained.

[0128] Due to the influence of many factors, the internal resistance r of the motor varies with the speed. In the above implementation mode, the internal resistance r1 of the motor under the no-load speed n0 can be determined. This implementation mode further considers that the change of the motor internal resistance with the no-load speed can also be represented by a curve function, and is preferably a quadratic curve function. Therefore, in practical applications, through 3 detections, the corresponding motor internal resistances under different no-load speeds can be determined, and then based on these motor internal resistances, a quadratic curve function of the motor internal resistance varying with the speed can be obtained.

[0129] When the specific value of N is 3, the quadratic curve function of the motor internal resistance r varying with the speed n can be expressed as , where ra, rb, and rc are the fitting curve constants of the quadratic curve function of the motor internal resistance varying with the speed, and are all unknowns. The values of ra, rb, and rc need to be determined through calculation. For example, in one case, based on the same principle, the internal resistance r1 of the motor under the no-load speed n0 is determined first, the internal resistance r2 of the motor under the no-load speed n1 is determined, and the internal resistance r3 of the motor under the no-load speed n2 is determined. Then, through r1, r2, and r3, the values of ra, rb, and rc can be obtained, which can be expressed as . After obtaining the values of ra, rb, and rc, the quadratic curve function of the motor internal resistance varying with the speed is determined. and it can be understood that by substituting any rotational speed into this quadratic curve function, the internal resistance of the motor under this rotational speed condition can be determined. Refer to Figure 10 , based on the internal resistance r1 of the motor under no-load rotational speed n0, the internal resistance r2 of the motor under no-load rotational speed n1, and the internal resistance r3 of the motor under no-load rotational speed n2, the quadratic curve function of the change of the motor internal resistance with the rotational speed can be determined.

[0130] In addition, it should also be noted that in this implementation manner, it is necessary to determine the corresponding internal resistance of the motor under different no-load rotational speed conditions. Refer to Figure 2 , by changing the magnitude of the output voltage Ep of the DC power supply, the magnitude of the no-load rotational speed can be adjusted. That is to say, at different magnitudes of Ep, in the manner described above, the detection of the internal resistance of the motor under the corresponding no-load rotational speed condition can be achieved.

[0131] Applying the technical solution provided by the embodiment of the present invention, when the motor is in the first state, the motor voltage, motor current, and no-load rotational speed in the first state will be determined. The first state means that the motor is connected to the DC power supply and runs no-load until it reaches a stable state. Therefore, it can be seen that the motor voltage, motor current, and no-load rotational speed obtained by the solution of this application are all relatively accurate values. The motor voltage and motor current in the first state are also the no-load voltage and no-load current, and according to the electromechanical equation of the motor running no-load, the magnitude of the no-load current depends on the no-load voltage, the internal resistance of the motor, and the back electromotive force of the motor at this time. Then, the motor switches from the first state to the second state, and it is necessary to determine the motor voltage and motor current at the initial moment of the second state. The second state means that the motor is disconnected from the DC power supply and then connected to the load resistance after disconnection, or freely decelerates after disconnection. Considering that the back electromotive force of the motor does not change suddenly during the switching instant, based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, according to the principle that the back electromotive force of the motor in the first state is consistent with the back electromotive force of the motor at the initial moment of the second state, the internal resistance of the motor under the no-load rotational speed condition can be determined. It can be seen that in the solution of this application, unlike the traditional solution where the internal resistance is calculated by using the voltage and current in the starting moment (stall) state of the motor, there will be no situation of poor repeatability and large error. That is to say, in the solution of this application, the accuracy of the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state can be effectively guaranteed, and thus the accuracy of the internal resistance of the motor under the determined no-load rotational speed condition can also be effectively guaranteed.

[0132] In summary, the solution of this application can effectively achieve the detection of the electromechanical parameters of the motor and ensure the accuracy of the detection.

[0133] Corresponding to the above method embodiments, the embodiments of the present invention further provide an electromechanical parameter detection system for a motor, which can be correspondingly referred to with the above text.

[0134] See Figure 11 As shown, it is a schematic structural diagram of an electromechanical parameter detection system for a motor in the present invention, including:

[0135] The first state detection module 201 is used to determine the motor voltage, motor current, and no-load speed in the first state when the motor is in the first state;

[0136] The second state detection module 202 is used to determine the motor voltage and motor current at the initial moment of the second state after the motor switches from the first state to the second state;

[0137] Among them, the first state means that the motor is connected to a DC power supply and runs no-load to a stable state; the second state means that the motor is disconnected from the DC power supply and a load resistor is connected after disconnection, or freely decelerates after disconnection;

[0138] The motor internal resistance determination module 203 is used to determine the motor internal resistance under no-load speed conditions based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force in the first state is consistent with the motor back electromotive force at the initial moment of the second state.

[0139] In a specific embodiment of the present invention, it further includes a back electromotive force constant determination module for:

[0140] Based on the motor voltage, motor current, no-load speed in the first state, and the determined motor internal resistance under no-load speed conditions, determine the motor back electromotive force constant.

[0141] In a specific embodiment of the present invention, the back electromotive force constant determination module is specifically used for:

[0142] Based on the motor voltage, motor current, no-load speed in the first state, and the determined motor internal resistance under no-load speed conditions, through The calculation method to determine the motor back electromotive force constant K e ;

[0143] Among them, V1 is the motor voltage in the first state; Is the motor current in the first state; n0 is the no-load speed in the first state; r1 is the determined motor internal resistance under the no-load speed n0; K eis the determined back electromotive force constant of the motor.

[0144] In a specific embodiment of the present invention, the motor internal resistance determination module 203 is specifically configured to:

[0145] Based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force E0 in the first state is consistent with the motor back electromotive force E0 at the initial moment of the second state, by the calculation method, determine the motor internal resistance r1 at the no-load speed n0;

[0146] wherein, V1 is the motor voltage in the first state; is the motor current in the first state; n0 is the no-load speed in the first state; r1 is the motor internal resistance at the no-load speed n0; E0 is the motor back electromotive force value at the no-load speed n0; V S is the motor voltage at the initial moment of the second state; is the motor current at the initial moment of the second state.

[0147] In a specific embodiment of the present invention, after the motor switches from the first state to the second state, determining the motor voltage at the initial moment of the second state includes:

[0148] Dividing the discharge period into X sampling intervals; wherein, the discharge period refers to the period from the start of the motor switching from the first state to the second state until the motor stops rotating; X is a positive integer not less than 2;

[0149] For each of the sampling intervals, take the integral mean of the motor voltage within the sampling interval as the motor voltage at the midpoint moment of the sampling interval;

[0150] Based on the motor voltages at the midpoint moments of the X sampling intervals respectively, obtain the (X - 1)-th order curve function of the motor voltage varying with time during the discharge period;

[0151] Based on the (X - 1)-th order curve function of the motor voltage varying with time during the discharge period, obtain the motor voltage at the initial moment of the second state.

[0152] In a specific embodiment of the present invention, when the second state is specifically that the motor is disconnected from the DC power supply and freely decelerates after disconnection, the determined motor current at the initial moment of the second state is 0;

[0153] When the second state is specifically that the motor is disconnected from the DC power supply and a load resistor is connected after the disconnection, after the motor switches from the first state to the second state, determining the motor current at the initial moment of the second state includes:

[0154] Dividing the discharge period into X sampling intervals; wherein, the discharge period represents the period from when the motor switches from the first state to the second state until the motor stops rotating; X is a positive integer not less than 2;

[0155] For each of the sampling intervals, taking the integral mean of the motor current within the sampling interval as the motor current at the midpoint moment of the sampling interval;

[0156] Based on the motor currents at the midpoint moments of the X sampling intervals respectively, obtaining an (X - 1)-order curve function of the motor current varying with time during the discharge period;

[0157] Based on the (X - 1)-order curve function of the motor current varying with time during the discharge period, obtaining the motor current at the initial moment of the second state.

[0158] In a specific embodiment of the present invention, it further includes a resistance change curve determination module for:

[0159] Through N detections, determining the corresponding motor internal resistance under different no-load speeds; wherein, N is a positive integer not less than 2,

[0160] Based on the determined corresponding motor internal resistances under different no-load speeds, obtaining an (N - 1)-order curve function of the motor internal resistance varying with speed.

[0161] Corresponding to the above method and system embodiments, an embodiment of the present invention further provides an electromechanical parameter detection device for a DC permanent magnet brushed motor and a computer-readable storage medium, which can be mutually corresponding and referred to with the above text.

[0162] See Figure 12 As shown, the device may include:

[0163] A memory 301 for storing a computer program;

[0164] A processor 302 for executing the computer program to implement the steps of the electromechanical parameter detection method for a DC permanent magnet brushed motor in any of the above embodiments.

[0165] A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, the steps of the method for detecting the electromechanical parameters of the DC permanent magnet brushed motor in any of the above embodiments are implemented. The computer-readable storage medium mentioned here includes random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium well-known in the technical field.

[0166] It should also be noted that in this application, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0167] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this application can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention. Specific examples are used in this application to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present invention. It should be noted that for those of ordinary skill in the technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A method for detecting the electromechanical parameters of a DC permanent magnet brushed motor, characterized in that, Including: When the motor is in the first state, determining the motor voltage, motor current, and no-load speed in the first state; After the motor switches from the first state to the second state, determining the motor voltage and motor current at the initial moment of the second state; Wherein, the first state means that the motor is connected to a DC power supply and runs no-load to a stable state; the second state means that the motor disconnects from the DC power supply and connects a load resistor after disconnection, or freely decelerates after disconnection; Based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force in the first state is consistent with the motor back electromotive force at the initial moment of the second state, determining the motor internal resistance under the no-load speed condition.

2. The electromechanical parameter detection method of the DC permanent magnet brushed motor according to claim 1, characterized in that, Further including: Based on the motor voltage, motor current, no-load speed in the first state, and the determined motor internal resistance under the no-load speed condition, determining the motor back electromotive force constant.

3. The electromechanical parameter detection method of the motor according to claim 2, characterized in that, Based on the motor voltage, motor current, no-load speed in the first state, and the determined motor internal resistance under the no-load speed condition, determining the motor back electromotive force constant, including: Based on the motor voltage, motor current, no-load speed in the first state, and the determined internal resistance of the motor at the no-load speed, through the calculation method, determine the motor back electromotive force constant K e ; Wherein, V1 is the motor voltage in the first state; is the motor current in the first state; n0 is the no-load speed in the first state; r1 is the determined internal resistance of the motor at the no-load speed n0; K e is the determined motor back EMF constant.

4. The electromechanical parameter detection method of the DC permanent magnet brushed motor according to claim 1, characterized in that Based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force in the first state is consistent with the motor back electromotive force at the initial moment of the second state, determining the motor internal resistance under the no-load speed condition, including: Based on the motor voltage and motor current in the first state, as well as the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force E0 in the first state is consistent with the motor back electromotive force E0 at the initial moment of the second state, through the calculation method, the motor internal resistance r1 under the no-load speed n0 is determined; Among them, V1 is the motor voltage in the first state; is the motor current in the first state; n0 is the no-load speed in the first state; r1 is the internal resistance of the motor at the no-load speed n0; E0 is the back electromotive force value of the motor at the no-load speed n0; V S is the motor voltage at the initial moment of the second state; is the motor current at the initial moment of the second state.

5. The electromechanical parameter detection method for the DC permanent magnet brushed motor according to claim 1, characterized in that, After the motor switches from the first state to the second state, determining the motor voltage at the initial moment of the second state, including: Dividing the discharge period into X sampling intervals; wherein, the discharge period means the period from when the motor switches from the first state to the second state until the motor stops rotating; X is a positive integer not less than 2; For each sampling interval, taking the integral mean of the motor voltage within the sampling interval as the motor voltage at the midpoint moment of the sampling interval; Based on the motor voltages at the midpoint moments of the X sampling intervals respectively, obtaining an (X - 1)-order curve function of the motor voltage varying with time during the discharge period; Based on the (X - 1)-order curve function of the motor voltage varying with time during the discharge period, obtaining the motor voltage at the initial moment of the second state.

6. The electromechanical parameter detection method of the DC permanent magnet brushed motor according to claim 1, characterized in that When the second state is specifically that the motor disconnects from the DC power supply and freely decelerates after disconnection, the determined motor current at the initial moment of the second state is 0; When the second state is specifically that the motor disconnects from the DC power supply and connects a load resistor after disconnection, after the motor switches from the first state to the second state, determining the motor current at the initial moment of the second state, including: Divide the discharge period into X sampling intervals; wherein, the discharge period refers to the period from when the motor switches from the first state to the second state until the motor stops rotating; X is a positive integer not less than 2; For each of the sampling intervals, take the integral mean of the motor current within the sampling interval as the motor current at the midpoint moment of the sampling interval; Based on the motor currents at the midpoint moments of the X sampling intervals respectively, obtain an (X - 1)-order curve function of the motor current varying with time within the discharge period; Based on the (X - 1)-order curve function of the motor current varying with time within the discharge period, obtain the motor current at the initial moment of the second state.

7. The method for detecting the electromechanical parameters of a DC permanent magnet brushed motor according to any one of claims 1 to 6, characterized in that, Further includes: Through N detections, determine the corresponding motor internal resistance under different no-load speeds; wherein, N is a positive integer not less than 2, Based on the determined corresponding motor internal resistances under different no-load speeds, obtain an (N - 1)-order curve function of the motor internal resistance varying with speed.

8. An electromechanical parameter detection system for a DC permanent magnet brushed motor, characterized in that, Includes: A first state detection module, configured to determine the motor voltage, motor current, and no-load speed in the first state when the motor is in the first state; A second state detection module, configured to determine the motor voltage and motor current at the initial moment of the second state after the motor switches from the first state to the second state; Wherein, the first state means that the motor is connected to a DC power supply and runs no-load to a stable state; the second state means that the motor disconnects from the DC power supply and connects a load resistor after disconnection, or freely decelerates after disconnection; A motor internal resistance determination module, configured to determine the motor internal resistance under the no-load speed condition based on the motor voltage and motor current in the first state, and the motor voltage and motor current at the initial moment of the second state, and in accordance with the principle that the motor back electromotive force in the first state is consistent with the motor back electromotive force at the initial moment of the second state.

9. An electromechanical parameter detection device for a DC permanent magnet brushed motor, characterized in that Includes: A memory, configured to store a computer program; A processor, configured to execute the computer program to implement the steps of the method for detecting the electromechanical parameters of a DC permanent magnet brushed motor according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer program is stored on a computer-readable storage medium, and when the computer program is executed by a processor, it implements the steps of the method for detecting the electromechanical parameters of a DC permanent magnet brushed motor according to any one of claims 1 to 7.

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