阅读说明：本技术 电机控制装置 (Motor control device ) 是由 蔡巍巍 肖涛 于 2020-07-22 设计创作，主要内容包括：一种电机控制装置,适于通过H桥驱动并联的多个电机,其包括：H桥,包括设置于第一高电位节点和第一低电位节点之间的并联的两个半桥,多个电机设置于两个半桥的中点之间；H桥控制模块,用于通过H桥的四个开关来控制对多个电机的电流馈给及多个电机的旋转方向；以及故障诊断模块,用于基于多个电机经未能使其转动的脉冲电压激励时对应的激励电流及经激励后多个电机所产生的释放电流来确定多个电机是否存在开路故障。本发明的电机控制装置具有成本低、占用的电路板面积小,并且能够实现对电机的开路故障进行检测和诊断等优点。(A motor control device adapted to drive a plurality of motors connected in parallel through an H-bridge, comprising: the H bridge comprises two half bridges which are arranged between a first high potential node and a first low potential node and connected in parallel, and a plurality of motors are arranged between the middle points of the two half bridges; the H bridge control module is used for controlling current feed to the motors and the rotating directions of the motors through four switches of the H bridge; and the fault diagnosis module is used for determining whether the motors have open-circuit faults or not based on corresponding excitation currents when the motors are excited by the pulse voltage which cannot enable the motors to rotate and release currents generated by the excited motors. The motor control device has the advantages of low cost, small occupied circuit board area, capability of realizing detection and diagnosis of the open-circuit fault of the motor and the like.)

1. A motor control device adapted to drive a plurality of motors connected in parallel through an H-bridge, comprising:

the H bridge comprises two half bridges which are arranged between a first high potential node and a first low potential node and connected in parallel, and the plurality of motors are arranged between the midpoints of the two half bridges;

an H-bridge control module for controlling current feed to the plurality of motors and rotational directions of the plurality of motors through four switches of the H-bridge; and

and the fault diagnosis module is used for determining whether the motors have open-circuit faults or not based on corresponding excitation currents when the motors are excited by the pulse voltage which cannot enable the motors to rotate and release currents generated by the motors after excitation.

2. The motor control apparatus of claim 1, further comprising a sampling resistor disposed on a loop of the excitation current between the half bridge and the first low potential node.

3. The motor control apparatus of claim 2 wherein a first node is formed between the sampling resistor and the half bridge to which it is connected, the fault diagnosis module determining whether an open circuit fault exists with the plurality of motors based on the voltage developed at the first node by the excitation current and the release current.

4. The motor control apparatus of claim 2 wherein the fault diagnostic module determines whether an open circuit fault exists with the plurality of motors based on the voltages generated by the excitation current and the release current at the midpoint of the half bridge of the sampled resistive connection.

5. The motor control device according to claim 3 or 4, wherein the plurality of motors are provided as n identical motors, and the excitation current and the release current are in the first stateThe peak value of the voltage generated at the node or the midpoint of the half bridge is V, the peak values of the voltages generated at the first node or the midpoint of the half bridge by the excitation current and the release current when the n motors are normal are Vr, and the peak values of the voltages generated at the node or the midpoint of the half bridge when the n motors are normal are VrThe fault diagnosis module determines that an open fault exists in the n motors.

6. The motor control apparatus of claim 1 wherein said pulsed voltage is generated by said H-bridge control module controlling the switching of four switches of said H-bridge.

7. The motor control apparatus of claim 1, further comprising:

a first pull-up resistor disposed between a midpoint of one of the half-bridges and a second high potential node;

a first pull-down resistor disposed between a midpoint of the other of the half-bridges and a second low potential node;

the fault diagnosis module is respectively connected with the middle points of the two half bridges, and determines whether the H bridge has a short-circuit fault or not based on the voltages of the middle points of the two half bridges.

8. The motor control apparatus of claim 7, wherein the fault diagnosis module determines that the H-bridge is short-circuited with the first high potential node if a voltage of a midpoint of two of the half-bridges is greater than or equal to 75% of a voltage of the first high potential node in a case where the H-bridge control module controls four switches in the H-bridge to be all open-circuited.

9. The motor control apparatus of claim 7, wherein the fault diagnosis module determines that the H-bridge is short-circuited with a first low potential node if a voltage of a midpoint of two half-bridges is less than or equal to 25% of a voltage of the first low potential node in a case where the H-bridge control module controls four switches in the H-bridge to be all open-circuited.

10. The motor control apparatus of claim 1, wherein the motor control apparatus is adapted to drive the plurality of motors to effect opening and/or closing of a power tailgate of a vehicle.

Technical Field

The invention relates to automotive electronics, in particular to a motor control device.

Background

The electric tail gate controller is an intelligent controller on a passenger car, and can drive an actuating mechanism to control the opening and closing of a back gate or a trunk lid of the car, and the electric tail gate opening and closing actuating mechanism generally comprises one or two electric support rods.

The electric tail gate controller generally drives a direct current brush motor inside the electric stay bar by a half-bridge driving circuit, and drives the stay bar mechanism to reciprocate to realize electric opening and closing of the tail gate through positive and negative rotation of the motor.

In the current technical solution, the electric tailgate controller generally drives two strut motors with three half-bridges, as shown in chinese utility model patent CN 208040159U. Besides the half-bridge circuit for driving the strut motor in the electric tail gate controller, the electric tail gate controller needs to be provided with a detection and diagnosis circuit for detecting and diagnosing the fault states of the switch tube and the motor. In the current technical scheme, three half-bridges, corresponding half-bridge driving circuits and detection and diagnosis circuits are needed for driving two strut motors, so that the problems of large material quantity, high cost and large occupied circuit board area exist.

Disclosure of Invention

The invention provides a motor control device which has the advantages of low cost, small occupied circuit board area, capability of detecting and diagnosing open-circuit faults of a motor and the like.

In order to solve the above problems, the present invention provides a motor control device adapted to drive a plurality of motors connected in parallel through an H-bridge, comprising: the H bridge comprises two half bridges which are arranged between a first high potential node and a first low potential node and connected in parallel, and the plurality of motors are arranged between the midpoints of the two half bridges; an H-bridge control module for controlling current feed to the plurality of motors and rotational directions of the plurality of motors through four switches of the H-bridge; and the fault diagnosis module is used for determining whether the motors have open-circuit faults or not based on corresponding excitation currents when the motors are excited by the pulse voltage which cannot enable the motors to rotate and release currents generated by the motors after excitation.

Compared with the prior art, the scheme has the following advantages:

the motor control device can realize the driving of a plurality of parallel motors only by two half bridges, and can realize the detection of the open circuit faults of the plurality of parallel motors. This effectively reduces material costs and board area occupied. In addition, the motor control device can also realize the detection of the short-circuit fault of the H bridge.

Drawings

FIG. 1 illustrates a schematic diagram of a motor control apparatus according to one or more embodiments of the present invention;

FIG. 2 illustrates a simulation result diagram in accordance with one or more embodiments of the invention.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention to those skilled in the art. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. Furthermore, it should be understood that the invention is not limited to the specific embodiments described. Rather, it is contemplated that the invention may be practiced with any combination of the following features and elements, whether or not they relate to different embodiments. Thus, the following aspects, features, embodiments and advantages are merely illustrative and should not be considered elements or limitations of the claims except where explicitly recited in a claim.

Fig. 1 illustrates a schematic diagram of a motor control apparatus according to one or more embodiments of the present invention. Referring to fig. 1, a motor control apparatus 10 includes an H-bridge 11, an H-bridge control module 12, and a fault diagnosis module 13. The motor control device 10 is adapted to drive a plurality of motors connected in parallel, such as a first motor M1 and a second motor M2 shown in fig. 1, through an H-bridge 11. It is understood that the number of the motors connected in parallel driven by the H-bridge 11 of the motor control apparatus 10 may be determined according to the specific application, and the present invention is not limited thereto.

The H-bridge 11 comprises a first half-bridge 11a and a second half-bridge 11b connected in parallel between a first high potential node and a first low potential node. The first and second motors M1 and M2 connected in parallel are disposed between midpoints of the first and second half bridges 11a and 11 b. The first half-bridge 11a comprises a first switch 11a1 and a second switch 11a2 connected in series. The second half-bridge 11b comprises a third switch 11b1 and a fourth switch 11b2 in series. In one or more embodiments, one or more of the first switch 11a1, the second switch 11a2, the third switch 11b1, and the fourth switch 11b2 may be a switch transistor, such as a PMOS switch transistor or an NMOS switch transistor. In one or more embodiments, the first high potential node may be a positive pole Vbat of a battery of the vehicle, and the first low potential node may be a negative pole of the battery of the vehicle, which may be, for example, grounded. The first high potential node and the first low potential node may have a voltage difference of 12V therebetween, for example.

The H-bridge control module 12 is connected to four switches in the H-bridge 11, respectively, and is configured to control current feeding to the plurality of motors and rotation directions of the plurality of motors through the four switches of the H-bridge 11. The H-bridge control module 12 may implement driving of the plurality of motors by outputting a pattern of high level or low level to four switches in the H-bridge 11, respectively. Specifically, the H-bridge control module 12 may output a high level to the first switch 11a1 and the fourth switch 11b2, turn on the first switch 11a1 and the fourth switch 11b2, output a low level to the second switch 11a2 and the third switch 11b1, and turn off the second switch 11a2 and the third switch 11b1, which drives the plurality of motors to rotate in a first direction, e.g., clockwise. The H-bridge control module 12 may output a low level to the first switch 11a1 and the fourth switch 11b2, turn off the first switch 11a1 and the fourth switch 11b2, output a high level to the second switch 11a2 and the third switch 11b1, and turn on the second switch 11a2 and the third switch 11b1, which may drive the plurality of motors to rotate in a second direction, e.g., counterclockwise.

The fault diagnosis module 13 is configured to determine whether an open-circuit fault exists in the plurality of motors based on corresponding excitation currents when the plurality of motors are excited by the pulse voltage that fails to rotate and release currents generated by the plurality of motors after excitation. The pulse voltage can be generated by controlling the on/off of four switches of the H-bridge 11 by the H-bridge control module 12.

Specifically, before the motor does not start moving, the inductance L and the resistance R of the motor coil are equivalent to a first-order series R-L circuit with a time constant of:

wherein, L is the equivalent inductance of the coils of the plurality of motors, and R is the equivalent resistance of the coils of the plurality of motors.

The unit step response of the coil currents of the plurality of motors is:

wherein, U is the power voltage during excitation, and t is the excitation time. As can be seen from the expressions (1) and (2), if an open-circuit motor exists among the plurality of motors, L and R at this time are different from those when the plurality of motors are all normal, which results in different currents when an open-circuit motor exists among the plurality of motors from those when the plurality of motors are all normal.

The pulse voltage magnetizes the inductance L of the motor coil, and the excitation energy is converted into magnetic field energy to be stored in the coil. After the pulse voltage excitation is finished, the magnetic field energy in the motor coil is converted into electric energy to form a release current. Because the open-circuit motors in the motors have different inductances L than the normal motors, the stored energy of the motor coils is different under the two conditions after the motors are excited by the same pulse voltage. Correspondingly, after the pulse voltage excitation is finished, the magnitude of the release current formed by converting the magnetic field energy in the motor coil into the electric energy is also different.

Therefore, whether the motors have open-circuit faults can be determined according to corresponding excitation currents when the motors are excited by the pulse voltage which can not drive the motors to rotate and release currents generated by the motors after excitation. For example, it may be determined whether there is an open-circuit motor in the plurality of motors at present by comparing the maximum value of the excitation current and the release current measured in the case where the plurality of motors are normal.

In one or more embodiments, the excitation time may take 3 τ to 5 τ. At the excitation time t equal to 3 tau, at the end of excitation, the currents of the multiple motors are

As can be seen from equation (3), when the excitation time t is 3 τ, the currents of the plurality of motors already approach U/R, that is, the amount of magnetization of the inductance L of the motor coil by the pulse voltage already approaches the magnetic storage capacity of the motor coil. In this case, a sufficiently large magnetic field energy is stored in the motor coil. It should be noted that the excitation time t can be adjusted according to the friction force of the mechanical system, and generally reaches 3 τ as much as possible without rotating the motor, so that the motor coil can store as much magnetic field energy as possible.

In one or more embodiments, the motor control apparatus 10 further includes a sampling resistor disposed on the excitation current loop between the half bridge and the first low potential node. It is understood that the motor control apparatus 10 includes two excitation current loops, (1) a loop in which the excitation current flows through the first high potential node, the third switch 11b1, the plurality of motors M1 and M2, the second switch 11a2, the first low potential node, with the sampling resistor 14a disposed between the second switch 11a2 and the first low potential node; (2) the exciting current flows through a loop of the first high potential node, the first switch 11a1, the plurality of motors M1 and M2, the fourth switch 11b2, and the first low potential node, and the sampling resistor 14b is disposed between the fourth switch 11b2 and the first low potential node. After the excitation of the pulse voltage is finished, a release current loop corresponding to the excitation current loop (1) is a loop passing through the first low potential node, the fourth switch 11b2, the plurality of motors M1 and M2, the second switch 11a2 and the first low potential node; the discharging current loop corresponding to the exciting current loop (2) is a loop passing through the first low potential node, the second switch 11a2, the plurality of motors M1 and M2, the fourth switch 11b2, the first low potential node. The sampling resistor 14a and/or the sampling resistor 14b may convert the excitation current and the discharge current into voltages from which the fault diagnostic module 13 may determine whether an open fault exists in the plurality of motors. For example, whether an open-circuit motor currently exists in the plurality of motors is determined by the peak value of the voltage generated on the sampling current by the measured excitation current and release current and the peak value of the voltage generated on the sampling current by the measured excitation current and release current in the case where the plurality of motors are normal.

In one or more embodiments, a first node 17a, 17b is formed between the sampling resistor 14a, 14b and the half bridge to which it is connected, and the fault diagnosis module 13 may determine whether an open fault exists in the plurality of motors based on the voltage generated at the first node by the excitation current and the release current.

In one or more embodiments, the fault diagnosis module 13 may determine whether an open fault exists for the plurality of motors based on the voltages generated by the excitation and release currents at the midpoints of the half bridges 11a, 11b connected by the sampling resistors 14a, 14 b.

Take the example that the plurality of motors are two identical motors M1 and M2. Under normal conditions, the equivalent inductance of the motor M1 and the motor M2 connected in parallel is:

wherein L is₁Is the coil inductance, L, of motor M1₂Is the inductance, L, of the coil of motor M2₁＝L₂。

Under normal conditions, the equivalent resistances of the motor M1 and the motor M2 connected in parallel are:

wherein R is₁Resistance value, R, of coil of motor M1₂Is the resistance value, R, of the coil of the motor M2₁＝R₂。

If the motor M1 has an open-circuit fault, the equivalent inductances of the motor M1 and the motor M2 connected in parallel at this time become:

L_s＝L₂#(6)

the equivalent resistance of the parallel motor M1 and motor M2 becomes:

R_s＝R₂#(7)

a first-order series R-L circuit, which is equivalent to the inductance L and the resistance R of the coils of the motor M1 and the motor M2 connected in parallel, can be calculated by the equation (1), and the time constant in the case where the motor M1 and the motor M2 are both normal is:

the time constant in the case of an open circuit fault in motor M1 is:

it can be seen that_n＝τ_s。

R can be obtained from the formula (5) and the formula (7)_n＝R_s/2. Due to tau_n＝τ_s、R_n＝R_s[ 2 ] i can be obtained according to the formula (2)_Ln(t)＝2i_Ls(t) in which i_Ln(t) is a unit step response of the coil currents of the plurality of motors when both the motor M1 and the motor M2 are normal, i_LsThe (t) is a unit step response of the coil currents of the plurality of motors when the motor M1 has an open-circuit fault and the motor M2 is normal. Therefore, it can be known that the excitation current and the release current when both the motor M1 and the motor M2 are normal are twice as large as the excitation current and the release current when the motor M1 is open and the motor M2 is normal, respectively.

Fig. 2 illustrates a simulation result when the inductances of the coils of the motor M1 and the motor M2 are both 0.2mH, the resistances are both 0.5 Ω, the voltage between the first high potential node and the first low potential node is 12V, and the pulse width of the pulse voltage is 1 ms. Fig. 2(a) shows a pulse voltage 201, a current curve 202 corresponding to the case where both the motor M1 and the motor M2 are normal, and a current curve 203 corresponding to the case where the motor M1 is open and the motor M2 is normal, and fig. 2(b) shows a voltage curve 204 and a voltage curve 205 corresponding to the case where the current is converted into a voltage by a sampling resistor, amplified, shaped, and biased.

Referring to fig. 2(a), the pulse voltage 201 jumps from low level to high level at 1ms, remains high for 1ms, and jumps back to low level at 2 ms. The current curve 202 corresponding to the normal operation of both the motor M1 and the motor M2 includes an excitation current 202a corresponding to the pulse voltage 201 at a high level and a discharge current 202b corresponding to the pulse voltage 201 returning to a low level. The current curve 203 corresponding to the open circuit of the motor M1 and the normal operation of the motor M2 includes the excitation current 203a corresponding to the pulse voltage 201 at the high level and the discharge current 203b corresponding to the pulse voltage 201 returning to the low level. As can be seen from fig. 2(a), at the corresponding time, the excitation current 202a is about twice the excitation current 203a, and the release current 202b is also about twice the excitation current 203 b. As can be seen from fig. 2(a), at the time when the pulse voltage 201 jumps from the high level to the low level, the current curve 202 has the maximum current value 202c, and the current curve 203 has the maximum current value 203 c. In one embodiment, it may be determined whether there is an open fault in motor M1 and motor M2 by comparing maximum current value 203c to maximum current value 202 c. Specifically, when maximum current value 203c is less than or equal to half of maximum current value 202c, it may be determined that an open fault exists.

Referring to fig. 2(b), the voltage curve 204 is about twice the voltage curve 205 after removing the voltage bias. Similar to the embodiment in which it is determined whether there is an open fault based on the current curve, the voltage peak in the voltage curve 205 may be compared with the voltage peak in the voltage curve 204 to determine whether there is an open fault in the motor M1 and the motor M2. Specifically, when the voltage peak in voltage curve 205 is less than or equal to half of the voltage peak of voltage curve 204, it may be determined that an open fault exists.

The following can be analogized based on the above analysis. Setting the multiple motors as n identical motors, setting the peak value of the voltage generated by the exciting current and the releasing current at the first node or the midpoint of the half bridge as V, setting the peak value of the voltage generated by the exciting current and the releasing current at the first node or the midpoint of the half bridge as Vr when the n motors are normal, and setting the peak value of the voltage generated by the exciting current and the releasing current at the first node or the midpoint of the half bridge when the n motors are normalThe fault diagnosis module 13 may determine that an open fault exists in the n motors.

With continued reference to fig. 1, the motor control device 10 further includes a first pull-up resistor 15 and a first pull-down resistor 16. The first pull-up resistor 15 is disposed between the midpoint of one half-bridge (e.g., half-bridge 11b) and the second high potential node VCC. The first pull-down resistor 16 is disposed between a midpoint of the other half-bridge (e.g., half-bridge 11a) and a second low potential node (e.g., ground). The fault diagnosis module 13 is connected to the midpoints of the two half bridges 11a, 11b, respectively, and determines whether there is a short-circuit fault in the H-bridge 11 based on the voltage of the midpoints of the two half bridges 11a, 11 b. The second high potential node and the second low potential node may have a voltage difference of, for example, 5V or 12V therebetween.

In the case where the H-bridge control module 12 controls all of the four switches 11a1, 11a2, 11b1, 11b2 in the H-bridge 11 to be open, the fault diagnosis module 13 may determine that the H-bridge 11 is short-circuited with the first high potential node if the voltage at the midpoint of the two half-bridges 11a, 11b is greater than or equal to 75% of the voltage VCC of the first high potential node.

In the case where the H-bridge control module 12 controls all of the four switches 11a1, 11a2, 11b1, 11b2 in the H-bridge to be open, the fault diagnosis module 13 may determine that the H-bridge 11 is short-circuited with the first low potential node if the voltage of the midpoint of the two half bridges 11a, 11b is less than or equal to 25% of the voltage VCC of the first low potential node.

In one or more embodiments, the motor control apparatus 10 is adapted to drive a plurality of motors M1, M2 to effect opening and/or closing of a power door of a vehicle.

As is apparent from the above description, the motor control apparatus 10 of the present invention can drive the plurality of parallel motors M1, M2 with only two half bridges 11a, 11b, and can detect an open fault of the plurality of parallel motors M1, M2. This effectively reduces material costs and board area occupied. In addition, the motor control device 10 of the present invention can also detect a short-circuit fault of the H-bridge 11.

Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this disclosure, and it is intended that the scope of the present invention be defined by the appended claims.