CN109633259B - A brushless motor power detection method - Google Patents

Abstract

The invention discloses a brushless motor power detection method. In the prior art, the motor power is calculated by the voltage value at both ends of the motor, that is, the power supply voltage. However, when the motor current is large, the power consumption of the power drive tube cannot be completely ignored. When the positive and negative lead resistances of the power supply cannot be ignored, the error of the motor power calculated according to this method is relatively large; the present invention provides a more accurate detection method, which firstly detects the instantaneous value of the voltage at both ends of the motor, and simultaneously detects the two ends of the sampling resistor. Voltage, further calculate and obtain the instantaneous value of current at both ends of the voltage, and calculate the power of the motor according to the instantaneous value of the voltage and the instantaneous value of the current. Accuracy of motor power.

Description

A brushless motor power detection method

technical field

The invention relates to the field of real-time detection of motors, in particular to a power detection method of a brushless motor.

Background technique

At present, most motor detection modules only detect the instantaneous value of the motor current. The default voltage value at both ends of the motor is the power supply voltage to calculate the motor power. However, when the motor current is large, the power consumption of the power drive tube or FET It cannot be completely ignored, and the resistance of the positive and negative leads of the power supply cannot be ignored either. At this time, the error of the motor power calculated according to the above method is relatively large.

In order to improve the accuracy of detecting the motor power, the present invention calculates the motor power by detecting the instantaneous value of the motor voltage and the instantaneous value of the current.

SUMMARY OF THE INVENTION

The present invention provides a monitoring method for motor power, and when the motor current is relatively large, accurate motor power can be obtained.

The technical scheme adopted by the present invention to solve the above-mentioned technical problems is:

A brushless motor power detection method adopts a motor power detection circuit to detect and calculate the power value of the motor, and the motor power detection circuit includes a drive circuit, a main controller, a Hall sensor, a motor, an inverter, a resistance network, Power supply Vin, ground GND, the motor includes motor windings, the resistance network includes a voltage detection module composed of multiple resistors and capacitors and a sampling resistor R ₄ , the inverter includes a first field effect transistor Q ₁ , The second field effect transistor Q ₂ , the third field effect transistor Q ₃ and the fourth field effect transistor Q ₄ , the sampling resistor R ₄ is connected in series with the second field effect transistor Q ₂ and the fourth field effect transistor Q ₄ and the ground GND between; the main controller includes a main control chip and an analog-to-digital converter inside the main control chip; the voltage detection module is connected in parallel with the motor, and the analog-to-digital converter inside the main control chip reads _The voltage Vis at both ends of the sampling resistor R4 is calculated to obtain the instantaneous current value of the motor winding; the analog-to-digital converter inside the main control chip reads the instantaneous voltage value at both ends of the motor, and the instantaneous voltage value of the motor winding is obtained by calculation, so The instantaneous power of the motor is obtained by multiplying the instantaneous voltage value of the motor winding by the instantaneous current value of the motor winding.

Another solution of the present invention is based on the above solution, the voltage detection module includes a first resistor R ₁ , a second resistor R ₂ , a third resistor R ₃ , a fifth resistor R ₅ , and a sixth resistor R ₆ , a seventh resistor R ₇ , a first capacitor C ₁ , and a second capacitor C ₂ ;

The drive circuit includes six pins, the main controller includes six pins, the Hall sensor includes one pin, the motor includes two pins, the first resistor R ₁ , the second resistor R ₂ , The third resistor R ₃ , the fifth resistor R ₅ , the sixth resistor R ₆ , the seventh resistor R ₇ , the first capacitor C ₁ , the second capacitor C ₂ , and the sampling resistor R ₄ respectively include two pins; The field effect transistor Q ₁ , the second field effect transistor Q ₂ , the third field effect transistor Q ₃ , and the fourth field effect transistor Q ₄ respectively include three feet;

The connection mode of the motor power detection circuit is as follows:

_The second pin of the sampling resistor R4 is connected to the _fourth pin of the main controller, the first pin of the sampling resistor R4 is connected to the ground GND _; the second pin of the sampling resistor R4, the second pin of the second field effect transistor _Q2 The second pin and the second pin of the fourth field effect transistor _Q4 are connected together;

The second leg of the _first resistor R1 is connected to the first leg of the motor, the _first resistor R1 and the _second resistor R2 are connected in series, and the first leg of the _first resistor R1 Connect with the second pin of the _second resistor R2 and the first pin of the third resistor _R3 , the second pin of the third resistor _R3 and the second pin of the first capacitor _{C1 The} pin is connected at point P1, the point P1 is connected to the fifth pin of the main controller, and the first pin of the _first capacitor _C1 is connected to the ground GND;

The second leg of the _fifth resistor R5 is connected to the second leg of the motor, the _fifth resistor R5 and the _sixth resistor R6 are connected in series, and the first leg of the _fifth resistor R5 Connect with the second pin of the _sixth resistor R6 and the second pin of the seventh resistor _R7 , the first pin of the seventh resistor _R7 and the second pin of the _second capacitor C2 _The pin is connected at point P2, the point P2 is connected to the sixth pin of the main controller, and the first pin of the _second capacitor _C2 is connected to the ground GND;

The third pin of the _first field effect transistor Q1 and the third pin of the third field effect transistor _Q3 are connected to the power supply Vin together;

The second pin of the _first field effect transistor Q1 and the third pin of the second field effect transistor _Q2 are jointly connected to the _first pin M1 of the motor;

The second pin of the third field effect transistor _Q3 and the third pin of the _fourth field effect transistor Q4 are jointly connected to the second pin _M2 of the motor;

The first pin of the first field effect transistor Q1 is connected with the _first pin of the driving circuit; the first pin of the second field effect transistor _Q2 is connected with the second pin of the driving circuit; the The first pin of the third field effect transistor _Q3 is connected with the third pin of the driving circuit; the first pin of the _fourth field effect transistor Q4 is connected with the fourth pin of the driving circuit;

The first pin of the main controller is connected with the fifth pin of the driving circuit; the second pin of the main controller is connected with the sixth pin of the driving circuit;

The detection method of the power of the brushless motor is as follows:

(1) Real-time detection of the instantaneous voltage values of points P ₁ and P ₂ in the motor power detection circuit, the detection method is: the analog-to-digital converter inside the main control chip converts the signal inputted by the fifth pin of the main control device Obtain the voltage value VP1 _of point _P1 ; the analog _- to-digital converter inside the main control chip converts the voltage value VP2 of point _P2 according to the signal input from the sixth pin of the main controller (102);

(2) Calculate the instantaneous voltage values V _M2 and V _M1 of the two ends M ₁ and M ₂ of the motor winding respectively,

V _M2 is calculated as follows:

V _M2 =I _M2 *(R ₅ +R ₆ ), I _M2 =V _P2 /R ₆ ,

V _M2 =V _P2 /R ₆ *(R ₅ +R ₆ )=(1+R ₅ /R ₆ )*V _P2

VM1 is calculated as follows:

V _M1 =I _M1 *(R ₁ +R ₂ ), I _M1 =V _P1 /R ₂ ,

V _M1 =V _P1 /R ₂ *(R ₁ +R ₂ )=(1+R ₁ /R ₂ )*V _P1

The voltage instantaneous value VMOTOR of the motor winding is calculated according to the following formula:

V _MOTOR =|V _M2 -V _M1 |=|(1+R ₅ /R ₆ )*V _P2 -(1+R ₁ /R ₂ )*V _P1 |

(3) Detect the current instantaneous value of the motor in real time, and the detection method is as follows: through analog-to-digital conversion through the fourth pin of the main controller, the voltage Vis on the resistor R ₄ is obtained by detection, and the current is calculated according to I _is =V _is /R ₄ . The instantaneous current value I _is of the current flowing through the resistor R ₄ , and the instantaneous current value of the motor winding is equal to the instantaneous current value of the current flowing through the resistor R ₄ ;

(4) Calculate the power P _MOTOR of the motor according to the instantaneous value of the voltage across the motor winding and the instantaneous value of the current of the motor winding, and the calculation method is: P _MOTOR =V _MOTOR *I _is .

The principles involved in the above technical solutions of the present invention include: according to the same current value of the series circuit and the same voltage value of the parallel circuit, voltage=current*resistance, motor winding power=motor winding instantaneous voltage*motor winding instantaneous current.

The positive effect that the technical scheme of the present invention produces is as follows:

(1) Real-time monitoring of the instantaneous power of the motor;

(2) Eliminate the power consumption of the power drive tube and the error of the positive and negative lead resistance of the power supply to the calculation of the motor power;

(3) Monitor the power consumption of the power drive tube in real time, so as to find out the abnormal situation of the power drive tube in time, remove the fault in time, and avoid burning out the motor.

Description of drawings

Figure 1 is a schematic diagram of the motor power detection;

Figure 2 is a power detection architecture diagram.

Description of reference numbers:

101 drive circuit

102 master controller

103 Hall sensor

104 Motor

105 voltage detection module

106 inverter

R1 _first resistor, R2 _second resistor, _R3 third resistor, R5 _fifth resistor, R6 _sixth resistor, _R7 seventh resistor

_C1 first capacitor, C2 _second capacitor

R ₄ sampling resistor

Q ₁ first FET, Q ₂ second FET, Q ₃ third FET, Q ₄ fourth FET

Vin power

GND ground

Detailed ways

An embodiment of the present invention is:

A brushless motor power detection method, using the motor power detection circuit shown in FIG. 1 to detect and calculate the power value of the motor, the motor power detection circuit includes a drive circuit 101, a main controller 102, a Hall sensor 103, The motor 104, the inverter 106, the resistor network, the power supply Vin, and the ground GND, the motor 104 includes a motor winding inside, and the resistor network includes a voltage detection module 105 composed of a plurality of resistors and capacitors and a sampling resistor R ₄ , so The inverter 106 includes a first field effect transistor Q ₁ , a second field effect transistor Q ₂ , a third field effect transistor Q ₃ , and a fourth field effect transistor Q ₄ , and the sampling resistor R ₄ is connected in series with the second field effect transistor between the transistor _Q2 and the fourth field effect transistor _Q4 and the ground GND; the main controller 102 includes a main control chip and an analog-to-digital converter inside the main control chip; the voltage detection module 105 and the The motors 104 are connected in parallel, the analog-to-digital converter inside the main control chip reads the voltage Vis at both ends of the sampling resistor R ₄ , and the instantaneous current value of the motor winding is obtained by calculation; the analog-to-digital converter inside the main control chip reads the motor 104 The instantaneous voltage value at both ends is calculated to obtain the instantaneous voltage value of the motor winding, and the instantaneous power of the motor is calculated by multiplying the instantaneous voltage value of the motor winding by the instantaneous current value of the motor winding.

Further, the voltage detection module 105 includes a first resistor R ₁ , a second resistor R ₂ , a third resistor R ₃ , a fifth resistor R ₅ , a sixth resistor R ₆ , a seventh resistor R ₇ , and a first capacitor C _1. The second capacitor C ₂ ;

As shown in FIG. 1 and FIG. 2 , the driving circuit 101 includes six pins, the main controller 102 includes six pins, the Hall sensor 103 includes one pin, and the motor 104 includes two pins. The first resistor R ₁ , the second resistor R ₂ , the third resistor R ₃ , the fifth resistor R ₅ , the sixth resistor R ₆ , the seventh resistor R ₇ , the first capacitor C ₁ , the second capacitor C ₂ , the sampling The resistor R ₄ includes two feet respectively; the first field effect transistor Q ₁ , the second field effect transistor Q ₂ , the third field effect transistor Q ₃ , and the fourth field effect transistor Q ₄ respectively include three feet;

The connection mode of the motor power detection circuit is as follows:

_The second pin of the sampling resistor R4 is connected to the _fourth pin of the main controller 102, the first pin of the sampling resistor R4 is connected to the ground GND _; the second pin of the sampling resistor R4, the second field effect transistor _Q2 The second pin of the MOSFET and the second pin of the fourth FET _Q4 are connected together;

The second leg of the _first resistor R1 is connected to the first leg of the motor 104, the _first resistor R1 and the _second resistor R2 are connected in series, and the first resistor R1 _of the first resistor is connected in series. The pin is connected to the second pin of the second resistor R2 and the first pin of the third resistor _R3 , and the _second pin of the third resistor _R3 is connected to the first pin of the first capacitor _C1 . The two pins are connected at the point P1, the point P1 is connected to the fifth pin of the main controller 102, and the _first pin of the _first capacitor _C1 is connected to the ground GND;

The second pin of the _fifth resistor R5 is connected to the second pin of the motor 104, the _fifth resistor R5 and the _sixth resistor R6 are connected in series, and the first pin of R5 of the _fifth resistor is connected in series. The pin is connected with the second pin of the _sixth resistor R6 and the second pin of the seventh resistor _R7 , and the first pin of the seventh resistor _R7 is connected to the _second pin of the second capacitor C2. The _two pins are connected at point P2, the point P2 is connected to the sixth pin of the main controller 102, and the first pin of the _second capacitor _C2 is connected to the ground GND;

The third pin of the _first field effect transistor Q1 and the third pin of the third field effect transistor _Q3 are connected to the power supply Vin together;

The second pin of the _first field effect transistor Q1 and the third pin of the second field effect transistor _Q2 are jointly connected to the _first pin M1 of the motor 104;

The second pin of the third field effect transistor _Q3 and the third pin of the _fourth field effect transistor Q4 are jointly connected to the second pin _M2 of the motor 104;

The first pin of the first field effect transistor Q1 is connected to the _first pin of the driving circuit 101; the first pin of the second field effect transistor _Q2 is connected to the second pin of the driving circuit 101; The first pin of the third field effect transistor _Q3 is connected to the third pin of the driving circuit 101; the first pin of the _fourth field effect transistor Q4 is connected to the fourth pin of the driving circuit 101;

The first pin of the main controller 102 is connected to the fifth pin of the driving circuit 101 ; the second pin of the main controller 102 is connected to the sixth pin of the driving circuit 101 ;

The detection method of the power of the brushless motor is as follows:

(1) Real-time detection of the instantaneous voltage values of points P ₁ and P ₂ in the motor power detection circuit, the detection method is: the analog-to-digital converter inside the main control chip is based on the signal input by the fifth pin of the main controller 102 Convert to obtain the voltage value VP1 _of point _P1 ; the analog _- to-digital converter inside the main control chip converts the voltage value VP2 of point _P2 according to the signal input from the sixth pin of the main controller 102;

(2) Calculate the instantaneous voltage values V _M2 and V _M1 of the two ends M ₁ and M ₂ of the motor winding respectively,

V _M2 is calculated as follows:

V _M2 =I _M2 *(R ₅ +R ₆ ), I _M2 =V _P2 /R ₆ ,

V _M2 =V _P2 /R ₆ *(R ₅ +R ₆ )=(1+R ₅ /R ₆ )*V _P2

V _M1 is calculated as follows:

V _M1 =I _M1 *(R ₁ +R ₂ ), I _M1 =V _P1 /R ₂ ,

V _M1 =V _P1 /R ₂ *(R ₁ +R ₂ )=(1+R ₁ /R ₂ )*V _P1

The instantaneous value of the motor winding voltage V _MOTOR is calculated according to the following formula:

V _MOTOR =|V _M2 -V _M1 |=|(1+R ₅ /R ₆ )*V _P2 -(1+R ₁ /R ₂ )*V _P1 |

(3) Detect the current instantaneous value of the motor 104 in real time. The detection method is as follows: through analog-to-digital conversion through the fourth pin of the main controller 102, the voltage Vis on the resistor R ₄ is detected and calculated according to I _is =V _is /R ₄ Obtain the instantaneous current value I _is of the current flowing through the resistor R ₄ , and the instantaneous current value of the motor winding is equal to the instantaneous current value of the current flowing through the resistor R ₄ ;

(4) Calculate the power P _MOTOR of the motor 104 according to the instantaneous value of the voltage across the motor winding and the instantaneous value of the current of the motor winding, and the calculation method is: P _MOTOR =V _MOTOR *I _is .

Further, the first pin of the driving circuit is Vgs1, the second pin is Vgs2, the third pin is Vgs3, the fourth pin is Vgs4, the fifth pin is DRV1, and the sixth pin is DRV1.

Further, the first pin of the main controller is DRV1, the second pin is DRV2, the third pin is connected to the HALL port (Hall signal input port), the fourth pin is connected to the sampling current Is input port, and the fifth pin is AD1. , the sixth pin is AD2.

The Vgs refers to the gate driving voltage of the FET, DRV refers to the driving signal, and AD1 and AD2 are the first digital input port and the second analog-digital input port, respectively.

The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the embodiments, and all technical solutions that belong to the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, several improvements and transformations without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims (1)

1. The brushless motor power detection method is characterized in that the motor power detection circuit comprises a driving circuit (101), a main controller (102), a Hall sensor (103), a motor (104), an inverter (106), a resistor network, a power source Vin and a ground GND, a motor winding is arranged in the motor (104), and the resistor network comprises a voltage detection module (105) consisting of a plurality of resistors and capacitors and a sampling resistor R₄The inverter (106) comprises a first field effect transistor Q₁And a second field effect transistor Q₂And a third field effect transistor Q₃And a fourth field effect transistor Q₄The sampling resistor R₄Is connected in series to a second field effect transistor Q₂And a fourth field effect transistor Q₄And ground GND; the master controller (102) comprises a master control chip and an analog-to-digital converter positioned in the master control chip; the voltage detection module (105) is connected with the motor (104) in parallel, and an analog-to-digital converter in the main control chip reads a sampling resistor R₄Calculating the voltage Vis at the two ends to obtain the instantaneous current value of the motor winding; an analog-digital converter in the main control chip reads instantaneous voltage values at two ends of a motor (104), instantaneous voltage values of a motor winding are obtained through calculation, and instantaneous power of the motor is obtained through multiplication of the instantaneous voltage values of the motor winding and instantaneous current values of the motor winding;

the voltage detection module (105) comprises a first resistor R₁A second resistor R₂A third resistor R₃A fifth resistor R₅A sixth resistor R₆A seventh resistor R₇A first capacitor C₁A second capacitor C₂；

The drive circuit (101) comprises six pins, the master controller (102) comprises six pins, the hall sensor (103) comprises one pin, the drive circuitThe motor (104) comprises two legs, the first resistor R₁A second resistor R₂A third resistor R₃A fifth resistor R₅A sixth resistor R₆A seventh resistor R₇A first capacitor C₁A second capacitor C₂Sampling resistor R₄Respectively comprises two feet; the first field effect transistor Q₁A second field effect transistor Q₂And a third field effect transistor Q₃And a fourth field effect transistor Q₄Respectively comprises three feet;

the connection mode of the motor power detection circuit is as follows:

the sampling resistor R₄Is connected to a fourth pin of the master controller (102), a sampling resistor R₄Is connected to ground GND; sampling resistor R₄Second pin and second field effect transistor Q₂Second pin and fourth field effect transistor Q₄The second legs of the first and second legs are connected together;

the first resistor R₁Is connected to a first leg of the motor (104), the first resistor R₁And said second resistance R₂In series, R of the first resistor₁First pin of (2) and the second resistor R₂And the third resistor R₃The first legs of the third resistor R are connected together, and the third resistor R₃And the first capacitor C₁Second leg of (2) is at P₁Point connection, P₁A fifth pin point-connected to the master (102), the first capacitor C₁The first pin of the transformer is connected with the ground GND;

the fifth resistor R₅Is connected to the second leg of the motor (104), and the fifth resistor R₅And the sixth resistor R₆R of the fifth resistor in series₅The first pin of (2) and the sixth resistor R₆And the seventh resistor R₇Is connected together, said seventh resistor R₇First pin of and the second capacitor C₂The second leg of (B) is at P₂Point connection, P₂A sixth pin point-connected to the master (102), the second capacitor C₂The first pin of the transformer is connected with the ground GND;

the first field effect transistor Q₁Third pin of (1) and the third field effect transistor Q₃Are connected together with a power source Vin;

the first field effect transistor Q₁Second pin of the second field effect transistor Q₂Is commonly connected to the first leg M of the motor (104)₁Point;

the third field effect transistor Q₃Second pin of the fourth field effect transistor Q₄Is connected to the second leg M of the motor (104)₂Point;

the first field effect transistor Q₁Is connected with a first pin of the driving circuit (101); the second field effect transistor Q₂Is connected with the second pin of the driving circuit (101); the third field effect transistor Q₃Is connected with the third pin of the driving circuit (101); the fourth field effect transistor Q₄Is connected with a fourth pin of the driving circuit (101);

the first pin of the main controller (102) is connected with the fifth pin of the driving circuit (101); the second pin of the main controller (102) is connected with the sixth pin of the driving circuit (101);

the detection method of the brushless motor power comprises the following steps:

(1) real-time detection P in motor power detection circuit₁Point, P₂The detection method of the voltage instantaneous value of the point comprises the following steps: an analog-to-digital converter in the main control chip converts a signal input by a fifth pin of the main controller (102) to obtain P₁Voltage value V of point_P1(ii) a An analog-to-digital converter in the main control chip converts a signal input by a sixth pin of the main controller (102) to obtain P₂Voltage value V of point_P2；

(2) Respectively calculating two end points M of motor winding₁、M₂Voltage instantaneous value V of_M2、V_M1，

V_M2The calculation method is as follows:

V_M2＝I_M2*(R₅+R₆)，I_M2＝V_P2/R₆，

V_M2＝V_P2/R₆*(R₅+R₆)＝(1+R₅/R₆)*V_P2

V_M1the calculation method is as follows:

V_M1＝I_M1*(R₁+R₂)，I_M1＝V_P1/R₂，

V_M1＝V_P1/R₂*(R₁+R₂)＝(1+R₁/R₂)*V_P1

instantaneous value V of voltage of motor winding_MOTORCalculated according to the following formula:

V_MOTOR＝|V_M2-V_M1|＝|(1+R₅/R₆)*V_P2-(1+R₁/R₂)*V_P1|

(3) the method for detecting the current instantaneous value of the motor (104) in real time comprises the following steps: the resistance R is obtained by the analog-to-digital conversion of the fourth pin of the main controller (102) through detection₄Voltage Vis on, according to I_is＝V_is/R₄Calculating to obtain a flow resistance R₄Current instantaneous current value I_isThe instantaneous current value of the motor winding is equal to the flow resistance R₄Current instantaneous current value of (a);

(4) calculating the power P of the motor (104) from the instantaneous value of the voltage across the motor winding and the instantaneous value of the current of the motor winding_MOTORThe calculation method comprises the following steps: p_MOTOR＝V_MOTOR*I_is。

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