CN113395030A

CN113395030A - Control device and method of motor driving system and motor

Info

Publication number: CN113395030A
Application number: CN202110688284.8A
Authority: CN
Inventors: 卢海洋; 区均灌; 王岩; 官鹏飞; 王芳
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-06-21
Filing date: 2021-06-21
Publication date: 2021-09-14

Abstract

The invention discloses a control device and a method of a motor driving system and a motor, wherein the device comprises: the three-phase current sampling module is used for sampling three-phase current of the motor to obtain a measured value; the control unit is used for establishing three coordinate systems with different axial orientations, and performing coordinate transformation on the measured value and the command value of the three-phase current of the motor under the three coordinate systems with different axial orientations to obtain the measured value and the command value of the alpha-axis stator current component; comparing the measured value with the command value to determine whether more than one phase of current sampling modules have faults; and under the condition that more than one phase of current sampling module has faults, carrying out fault-tolerant processing on the measured value of the current sampling module with the faults, and then controlling the running condition of the motor. According to the scheme, the three-phase current sampling module is used for current sampling, and fault diagnosis and fault-tolerant control are performed on the three-phase current sampling module, so that stable operation of the motor when a fault occurs is guaranteed.

Description

Control device and method of motor driving system and motor

Technical Field

The invention belongs to the technical field of motors, and particularly relates to a control device and method of a motor driving system and a motor, in particular to a servo system with current sampling fault detection and fault-tolerant control, a motor and a current sampling fault detection and fault-tolerant control method of the motor.

Background

Servo drivers (also called servo controllers or servo amplifiers) are controllers for controlling servo motors, act on common alternating current motors, are similar to frequency converters, belong to a part of servo systems, and are mainly applied to high-precision positioning systems.

In the related art, most servo drivers collect two-phase currents by using current sensors for loop control (i.e., current loop control). However, if the current sensor fails, the servo driver may misdiagnose the operating state of the motor, which may affect the operating stability of the motor.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The invention aims to provide a control device and a control method of a motor driving system and a motor, which aim to solve the problems that a servo driver carries out current loop control by using two-phase current collected by a current sensor, and the error diagnosis of the servo driver on the working state of the motor can be caused and the operation stability of the motor is influenced once the current sensor fails, so that the effects of carrying out current sampling by using three current sensors and carrying out fault diagnosis and fault-tolerant control on the three current sensors to ensure the stable operation of the motor when a fault occurs are achieved.

The present invention provides a control device of a motor drive system, including: a sampling unit and a control unit; the sampling unit includes: a three-phase current sampling module; the three-phase current sampling module is configured to sample three-phase current of the motor under the condition that the motor is operated, so as to obtain a measured value of the three-phase current of the motor; the control unit is configured to establish three coordinate systems with different axial orientations, and perform coordinate transformation on the measured values and the instruction values of the three-phase current of the motor under the three coordinate systems with different axial orientations to obtain the measured values and the instruction values of the alpha-axis stator current components under the three coordinate systems with different axial orientations; comparing measured values and command values of the alpha-axis stator current components in three coordinate systems with different axial orientations to determine whether more than one phase of current sampling modules in the three-phase current sampling modules have faults; and when more than one phase of current sampling module in the three-phase current sampling module has a fault, carrying out fault-tolerant processing on the measured value of the faulted more than one phase of current sampling module, and then controlling the running condition of the motor.

In some embodiments, the control unit, which establishes three coordinate systems with different axial orientations, performs coordinate transformation on the measured values and the command values of the three-phase current of the motor in the three coordinate systems with different axial orientations to obtain the measured values and the command values of the α -axis stator current components in the three coordinate systems with different axial orientations, includes: establishing three coordinate systems according to the phase a orientation, the phase b orientation and the phase c orientation respectively to obtain a first coordinate system, a second coordinate system and a third coordinate system; performing Clark transformation on the measured values of the three-phase current of the motor under three coordinate systems with different axial orientations to obtain measured values of the current components of the alpha and beta axial stators, and selecting the measured value of the current component of the alpha axial stator; and carrying out Park inverse transformation on the instruction values of the currents of the d axis and the q axis under three coordinate systems with different axis orientations to obtain the instruction values of the stator current components of the alpha axis and the beta axis, and selecting the instruction value of the stator current component of the alpha axis.

In some embodiments, three coordinate systems oriented in different axes include: a first coordinate system, a second coordinate system and a third coordinate system are respectively established according to the phase a orientation, the phase b orientation and the phase c orientation; the control unit compares the measured value and the command value of the alpha-axis stator current component under three coordinate systems with different axial orientations to determine whether more than one phase of current sampling modules in the three-phase current sampling modules have faults or not, and comprises the following steps: determining whether the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in each coordinate system is greater than the set threshold value in the coordinate system or not based on the measured value and the command value of the alpha-axis stator current component in the three coordinate systems with different axial orientations; if the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in the first coordinate system is larger than the set threshold value in the first coordinate system, determining that the a-phase current sampling module has a fault; otherwise, determining that the a-phase current sampling module is not in fault; if the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in the second coordinate system is larger than the set threshold value in the second coordinate system, determining that the b-phase current sampling module has a fault; otherwise, determining that the b-phase current sampling module is not in fault; if the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in the third coordinate system is larger than the set threshold value in the third coordinate system, determining that the c-phase current sampling module fails; otherwise, determining that the c-phase current sampling module is not in fault.

In some embodiments, when one or more of the three-phase current sampling modules fails, the control unit performs fault-tolerant processing on a measurement value of the failed one or more current sampling modules, and then controls the operation of the motor, including: recording the logic value of the condition whether each phase of current sampling module has a fault or not; determining the phase number of the current sampling module which has a fault condition in the three-phase current sampling module according to the logic value of whether the three-phase current sampling module has the fault condition; if the phase number of the current sampling module which has a fault condition in the three-phase current sampling module is one phase, carrying out fault-tolerant processing on the measured value of the faulted one-phase current sampling module according to a first fault-tolerant processing mode, and then controlling the running condition of the motor; if the phase number of the current sampling module with the fault condition in the three-phase current sampling module is two-phase or three-phase, the measured value of the current sampling module with more than two phases with the fault is subjected to fault-tolerant processing according to a second fault-tolerant processing mode, and then the running condition of the motor is controlled.

In some embodiments, the fault-tolerant processing of the measured value of the failed one-phase current sampling module by the control unit in a first fault-tolerant processing mode includes: and determining the current values of the alpha shaft and the beta shaft and the value of the electrical angle corresponding to the logic value of the fault condition of the three-phase current sampling module according to the first corresponding relation between the set logic value of the fault condition of the three-phase current sampling module and the set current values of the alpha shaft and the beta shaft and the set value of the electrical angle.

In some embodiments, further comprising: an observation unit; the control unit carries out fault-tolerant processing on the measured value of the current sampling module with more than two phases with faults according to a second fault-tolerant processing mode, and the fault-tolerant processing method comprises the following steps: estimating the rotating speed through the observation unit according to the rotating speed of the motor and the d-axis and q-axis voltages to obtain estimated values of d-axis and q-axis currents; carrying out Park inverse transformation on the estimated values of the d-axis current and the q-axis current respectively under three coordinate systems to obtain estimated values of the alpha-axis current and the beta-axis current; if the two-phase current sampling module has a fault, determining the current value of the alpha axis and the value of the electrical angle corresponding to the logic value of the three-phase current sampling module if the three-phase current sampling module has the fault according to a second corresponding relation between the set logic value of the three-phase current sampling module if the three-phase current sampling module has the fault and the set current value of the alpha axis and the set value of the electrical angle; selecting an estimated value of the beta axis current in the estimated values of the alpha axis current and the beta axis current as a current value of the beta axis corresponding to a logic value of whether the three-phase current sampling module has a fault condition; if the three-phase current sampling module fails, selecting estimated values of alpha and beta axis currents as current values of alpha and beta axes corresponding to the logical value of whether the three-phase current sampling module fails; and determining the value of the electrical angle corresponding to the logical value of the three-phase current sampling module whether the fault condition occurs according to a second corresponding relation between the set logical value of the three-phase current sampling module whether the fault condition occurs and the set current value of the alpha axis and the set value of the electrical angle.

In some embodiments, further comprising: a reminding unit; the reminding unit is configured to remind whether the three-phase current sampling module has a fault condition.

In accordance with another aspect of the present invention, there is provided a motor including: the control device of the motor drive system described above.

In accordance with the above motor, a further aspect of the present invention provides a method for controlling a motor driving system, including: sampling three-phase current of the motor through a three-phase current sampling module under the condition that the motor runs to obtain a measured value of the three-phase current of the motor; establishing three coordinate systems with different axial orientations through a control unit, and performing coordinate transformation on the measured values and the instruction values of the three-phase current of the motor under the three coordinate systems with different axial orientations to obtain the measured values and the instruction values of the alpha-axis stator current components under the three coordinate systems with different axial orientations; comparing measured values and command values of the alpha-axis stator current components in three coordinate systems with different axial orientations to determine whether more than one phase of current sampling modules in the three-phase current sampling modules have faults; and when more than one phase of current sampling module in the three-phase current sampling module has a fault, carrying out fault-tolerant processing on the measured value of the faulted more than one phase of current sampling module, and then controlling the running condition of the motor.

In some embodiments, establishing, by the control unit, three coordinate systems with different axial orientations, and performing coordinate transformation on the measured values and the command values of the three-phase current of the motor in the three coordinate systems with different axial orientations to obtain the measured values and the command values of the α -axis stator current components in the three coordinate systems with different axial orientations includes: establishing three coordinate systems according to the phase a orientation, the phase b orientation and the phase c orientation respectively to obtain a first coordinate system, a second coordinate system and a third coordinate system; performing Clark transformation on the measured values of the three-phase current of the motor under three coordinate systems with different axial orientations to obtain measured values of the current components of the alpha and beta axial stators, and selecting the measured value of the current component of the alpha axial stator; and carrying out Park inverse transformation on the instruction values of the currents of the d axis and the q axis under three coordinate systems with different axis orientations to obtain the instruction values of the stator current components of the alpha axis and the beta axis, and selecting the instruction value of the stator current component of the alpha axis.

In some embodiments, three coordinate systems oriented in different axes include: a first coordinate system, a second coordinate system and a third coordinate system are respectively established according to the phase a orientation, the phase b orientation and the phase c orientation; through the control unit, according to the measured value and the instruction value of alpha axle stator current component under the directional coordinate system of three disalignment, confirm whether have more than one looks current sampling module in the three-phase current sampling module to break down, include: determining whether the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in each coordinate system is greater than the set threshold value in the coordinate system or not based on the measured value and the command value of the alpha-axis stator current component in the three coordinate systems with different axial orientations; if the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in the first coordinate system is larger than the set threshold value in the first coordinate system, determining that the a-phase current sampling module has a fault; otherwise, determining that the a-phase current sampling module is not in fault; if the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in the second coordinate system is larger than the set threshold value in the second coordinate system, determining that the b-phase current sampling module has a fault; otherwise, determining that the b-phase current sampling module is not in fault; if the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in the third coordinate system is larger than the set threshold value in the third coordinate system, determining that the c-phase current sampling module fails; otherwise, determining that the c-phase current sampling module is not in fault.

In some embodiments, when one or more of the three-phase current sampling modules fails, the control unit performs fault-tolerant processing on a measurement value of the failed one or more current sampling modules and then controls the operation of the motor, including: recording the logic value of the condition whether each phase of current sampling module has a fault or not; determining the phase number of the current sampling module which has a fault condition in the three-phase current sampling module according to the logic value of whether the three-phase current sampling module has the fault condition; if the phase number of the current sampling module which has a fault condition in the three-phase current sampling module is one phase, carrying out fault-tolerant processing on the measured value of the faulted one-phase current sampling module according to a first fault-tolerant processing mode, and then controlling the running condition of the motor; if the phase number of the current sampling module with the fault condition in the three-phase current sampling module is two-phase or three-phase, the measured value of the current sampling module with more than two phases with the fault is subjected to fault-tolerant processing according to a second fault-tolerant processing mode, and then the running condition of the motor is controlled.

In some embodiments, the fault-tolerant processing of the measured values of the current sampling modules of two or more phases with faults by the control unit in a second fault-tolerant processing mode includes: estimating the rotating speed through an observation unit according to the rotating speed of the motor and the d-axis and q-axis voltages to obtain estimated values of d-axis and q-axis currents; carrying out Park inverse transformation on the estimated values of the d-axis current and the q-axis current respectively under three coordinate systems to obtain estimated values of the alpha-axis current and the beta-axis current; if the two-phase current sampling module has a fault, determining the current value of the alpha axis and the value of the electrical angle corresponding to the logic value of the three-phase current sampling module if the three-phase current sampling module has the fault according to a second corresponding relation between the set logic value of the three-phase current sampling module if the three-phase current sampling module has the fault and the set current value of the alpha axis and the set value of the electrical angle; selecting an estimated value of the beta axis current in the estimated values of the alpha axis current and the beta axis current as a current value of the beta axis corresponding to a logic value of whether the three-phase current sampling module has a fault condition; if the three-phase current sampling module fails, selecting estimated values of alpha and beta axis currents as current values of alpha and beta axes corresponding to the logical value of whether the three-phase current sampling module fails; and determining the value of the electrical angle corresponding to the logical value of the three-phase current sampling module whether the fault condition occurs according to a second corresponding relation between the set logical value of the three-phase current sampling module whether the fault condition occurs and the set current value of the alpha axis and the set value of the electrical angle.

In some embodiments, further comprising: and the reminding unit is used for reminding whether the three-phase current sampling module has a fault or not.

Therefore, according to the scheme of the invention, the three-phase current sampling module is used for current sampling, three coordinate systems with different axial orientations are established, the fault information of the three-phase current sampling module is judged according to the comparison between the measured value and the command value of the alpha-axis stator current component in the three coordinate systems with different axial orientations, and when the current sampling modules with more than two phases have faults, the estimated current replaces the measured current to carry out motor drive control so as to ensure that the motor stably runs when the faults occur; therefore, the three-phase current sampling module is used for current sampling, and fault diagnosis and fault-tolerant control are carried out on the three-phase current sampling module, so that stable operation of the motor when a fault occurs is ensured.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

Fig. 1 is a schematic structural diagram of a control device of a motor drive system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an embodiment of a fault tolerant servo control system;

FIG. 3 is a schematic view of a coordinate system I oriented with the stator a phase;

FIG. 4 is a schematic view of coordinate system II oriented with stator b phase;

FIG. 5 is a schematic view of coordinate system III oriented in stator c-phase;

FIG. 6 is a schematic structural diagram of an embodiment of an adaptive back-stepping observer;

FIG. 7 is a flowchart illustrating a control method of the motor driving system according to an embodiment of the present invention;

FIG. 8 is a schematic flow chart of one embodiment of coordinate transformation in a coordinate system of three different axial orientations for measured and commanded values of three phase currents of the motor in the method of the present invention;

FIG. 9 is a schematic flow chart illustrating one embodiment of determining whether one or more of the three-phase current sampling modules have failed in the method of the present invention;

FIG. 10 is a flow chart illustrating an embodiment of fault tolerance processing of the measured values of more than one phase current sampling module in which a fault occurs in the method of the present invention;

FIG. 11 is a flowchart illustrating an embodiment of fault-tolerant processing of the measured values of two or more failed current sampling modules according to the method of the present invention.

The reference numbers in the embodiments of the present invention are as follows, in combination with the accompanying drawings:

102-a sampling unit; 104-control unit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In view of most servo drives, two-phase current is collected using a current sensor for loop control (i.e., current loop control). However, due to the lack of fault diagnosis and fault-tolerant control for the sensor, once the current sensor fails, the working state of the motor is misdiagnosed, and the performance of the motor driving system is seriously affected, for example, the working reliability of the motor driving system is affected, and further, the operation stability of the motor is affected.

In some schemes, a fault-tolerant drive control scheme of a motor with self-repairing faults is adopted, but only the single-phase problem situation can be solved, and if two phases or three phases have problems, the fault-tolerant drive control system of the motor is not applicable and has high cost.

In other schemes, a direct current motor control system fault diagnosis scheme is adopted, but according to U, V, W three-phase current signals and phase current overcurrent signals F_OThe method determines whether the direct current motor control system has faults and the reasons of the faults, and although the method is low in cost and simple to implement, once the faults occur, the motor system cannot normally operate and is lack of fault-tolerant design.

According to an embodiment of the present invention, there is provided a control apparatus of a motor drive system. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The motor drive system includes: and (4) current loops. The control device of the motor drive system includes: a sampling unit 102 and a control unit 104. The sampling unit 102 includes: and a three-phase current sampling module. A three-phase current sampling module, such as a three-phase current sensor. A control unit 104, such as the fault tolerant control portion shown in fig. 2.

The three-phase current sampling module is configured to sample three-phase currents of the motor when the motor is running, such as U, V, W three-phase currents of the motor, and obtain measured values of the three-phase currents of the motor. The motor control device comprises a motor, a phase current sampling module and a phase current measuring module, wherein the phase current sampling module is used for sampling a phase current of the motor under the condition that the motor runs to obtain a measured value of the phase current of the motor. For example: when the motor runs, the U, V, W-phase current of the motor is respectively sampled by the three current sensors to obtain the corresponding current value i_a、i_b、i_c。i_aCurrent value, i, of U-phase current of motor_bCurrent value, i, of the V-phase current of the motor_cThe current value of the W-phase current of the motor. In the related art, two current sensors are basically used for current sampling. Book and notebookThe scheme of the invention uses three current sensors to sample current, and is used in places with higher requirements on precision and reliability.

The control unit 104 is configured to establish three coordinate systems with different axial orientations, and perform coordinate transformation on the measured values and the command values of the three-phase current of the motor in the three coordinate systems with different axial orientations to obtain the measured values and the command values of the α -axis stator current components in the three coordinate systems with different axial orientations. And the number of the first and second groups,

in some embodiments, the control unit 104, establishing three coordinate systems with different axial orientations, and performing coordinate transformation on the measured values and the command values of the three-phase currents of the motor in the three coordinate systems with different axial orientations to obtain the measured values and the command values of the α -axis stator current components in the three coordinate systems with different axial orientations, includes:

the control unit 104 is further specifically configured to establish three coordinate systems according to the phase a orientation, the phase b orientation, and the phase c orientation, respectively, to obtain a first coordinate system, a second coordinate system, and a third coordinate system. A first coordinate system, such as coordinate system I. A second coordinate system, such as coordinate system II. A third coordinate system, such as coordinate system III.

The control unit 104 is specifically further configured to perform Clark transformation on the measured values of the three-phase current of the motor in three coordinate systems with different axial orientations, obtain measured values of α -axis stator current components and β -axis stator current components, and select the measured value of the α -axis stator current component.

The control unit 104 is specifically configured to perform Park inverse transformation on the instruction values of the currents of the d and q axes in three coordinate systems with different axial orientations, obtain instruction values of the stator current components of the α and β axes, and select the instruction value of the stator current component of the α axis.

Specifically, according to coordinate transformation of different axis orientations, measured values and instruction values of stator current components of the alpha axis and the beta axis are obtained.

Fig. 3 is a schematic view of a stator a oriented coordinate system I, fig. 4 is a schematic view of a stator b oriented coordinate system II, and fig. 5 is a schematic view of a stator c oriented coordinate system III. Respectively according to the a phase orientation,b-phase orientation and c-phase orientation, establishing three coordinate systems I, II and III (shown in figures 3, 4 and 5), and obtaining the measured values i of the stator current components of the alpha and beta axes through Clark transformation_α ^I,II,IIIAnd i_β ^I,II,III. At the same time, according to the current commands i of d and q axes_d ^*And i_q ^*Obtaining command values i of the stator current components of the alpha and beta axes through Park inverse transformation_α ^*I,II,IIIAnd i_β ^*I,II,III。

According to the stator a-phase orientation, the a-phase axis coincides with the α -axis, as shown in fig. 3, and at this time, the Clark transformation and Park inverse transformation formulas are as follows:

in the formula (1) and the formula (2), θ is an angle between the d axis and the a axis in the synchronous rotation coordinate system (i.e. dq coordinate system), i_a、i_bCurrent values of a-phase current and b-phase current measured by a current sensor, i_d ^*、i_q ^*The command values are d and q-axis currents. i.e. i_α ^I、i_β ^IIs measured value I of alpha and beta axis current in coordinate system I (namely alpha and beta coordinate system)_α ^*I、i_β ^*IThe command values are α and β axis currents.

As can be seen from equation (1), the α -axis current is related to only the a-phase current, and therefore, i is calculated by using i_α ^IAnd i_α ^*IComparing to determine i_α ^IAnd judging whether the a-phase current sensor is abnormal or not so as to judge whether the a-phase current sensor is in failure or not. Similarly, the phases b and c are also used for sequentially judging whether the corresponding current sensor has a fault.

The control unit 104 is specifically configured to compare the measured value and the command value of the α -axis stator current component in three coordinate systems oriented in different axes, and determine whether more than one phase of the three-phase current sampling modules has a fault. And the number of the first and second groups,

in some embodiments, three coordinate systems oriented in different axes include: and a first coordinate system, a second coordinate system and a third coordinate system are respectively established according to the phase a orientation, the phase b orientation and the phase c orientation.

The control unit 104 compares the measured value and the command value of the α -axis stator current component in the three coordinate systems oriented along different axes to determine whether more than one phase of current sampling modules in the three-phase current sampling modules has a fault, and includes:

the control unit 104 is specifically further configured to determine, based on the measured values and the command values of the α -axis stator current components in the three coordinate systems oriented in different axes, whether the absolute values of the deviation values of the measured values and the command values of the α -axis stator current components in each coordinate system are greater than the set threshold value in the coordinate system.

The control unit 104 is further specifically configured to determine that the a-phase current sampling module fails if an absolute value of a deviation value between the measured value and the command value of the α -axis stator current component in the first coordinate system is greater than a set threshold in the first coordinate system. Otherwise, the a-phase current sampling module is determined not to be in fault.

The control unit 104 is further specifically configured to determine that the b-phase current sampling module fails if an absolute value of a deviation value between the measured value and the command value of the α -axis stator current component in the second coordinate system is greater than a set threshold in the second coordinate system. Otherwise, determining that the b-phase current sampling module is not in fault.

The control unit 104 is further specifically configured to determine that the c-phase current sampling module fails if an absolute value of a deviation value between the measured value and the command value of the α -axis stator current component in the third coordinate system is greater than a set threshold in the third coordinate system. Otherwise, determining that the c-phase current sampling module is not in fault.

Specifically, a measured value i of the alpha-axis stator current component is obtained according to the previous period_α ^I,II,IIIAnd an instruction value i_α ^*I,II^,IIIAnd calculating the deviation value delta of the two current sensors and judging the fault information of the three current sensors. Epsilon₁、ε₂And epsilon₃For the safety threshold, the threshold size may be set according to the actual use condition. The safety threshold value is set by considering the influence caused by errors such as rotating speed and load sudden change, the value is not too small, enough margin needs to be reserved, and the rotating speed and load sudden change cannot cause misdiagnosis; the value of the fault diagnosis method is not suitable to be too large, and the speed and the precision of fault diagnosis are improved.

Let delta₁＝i_α ^I-i_α ^*I，δ₂＝i_α ^II-i_α ^*II，δ₃＝i_α ^III-i_α ^*IIIThe following judgment is made:

and 31, judgment: if delta₁|＞ε₁Then i is_α ^IAbnormal, the a-phase current sensor fails. Whereas if delta₁|＜ε₁Then i is_α ^INormally, the a-phase current sensor is normal.

And (6) judging: if delta₂|＞ε₂Then i is_α ^IIAbnormal, the b-phase current sensor fails. Whereas if delta₂|＜ε₂Then i is_α ^IINormally, the b-phase current normal sensor is normal.

And (3) judgment: if delta₃|＞ε₃Then i is_α ^IIIAbnormal, the c-phase current sensor fails. Whereas if delta₃|＜ε₃Then i is_α ^IIINormally, the c-phase current sensor is normal.

The control unit 104 is specifically configured to, when one or more of the three-phase current sampling modules fails, perform fault-tolerant processing on a measurement value of the failed one or more current sampling modules, and then control the operation condition of the motor.

FIG. 2 is a schematic diagram of an embodiment of a fault-tolerant servo control system (i.e., a servo system with current sampling fault detection and fault-tolerant control). The fault-tolerant servo control system shown in fig. 2 is specifically a current sampling fault detection and fault-tolerant control device, and is composed of a Clark transformation part, a Park inverse transformation part, a self-adaptive backstepping observer and a fault-tolerant control part. Wherein, Clark transformation is to transform abc into a stationary alpha beta coordinate system. And performing Park inverse transformation, namely transforming abc into a rotating dq coordinate system.

As shown in fig. 2, the current loop adopts a closed-loop control scheme, which requires obtaining an accurate current feedback value, and if a certain phase current sensor fails and is not processed, the normal operation of the motor is affected. Therefore, the three-phase current sensor needs to be detected, and if the current sensor fails, fault-tolerant control is performed on the current sensor, so that the motor can normally run.

Thus, the scheme of the invention establishes three coordinate systems with different axial orientations through a control device of a motor driving system, such as a servo system with current sampling fault detection and fault-tolerant control, compares command values (namely given values) and measured values of alpha-axis stator current components in the three coordinate systems with different axial orientations, and judges fault information of three current sensors. A logic judgment mechanism is designed according to the three coordinate systems, and when a fault occurs, the proper estimated current is used for replacing the measured current to carry out feedback so as to reconstruct a system, so that the stable operation of the motor is ensured when the fault occurs.

A coordinate system of different axial orientations, comprising: as oriented by stator a phase: the phase axis of the stator a is coincident with the alpha axis; as oriented by stator b phase: the phase axis of the stator b is coincident with the alpha axis; as oriented by stator c phase: the stator c phase axis coincides with the alpha axis.

In some embodiments, when one or more of the three-phase current sampling modules fails, the control unit 104 performs fault-tolerant processing on the measurement value of the failed one or more phase current sampling modules, and then controls the operation of the motor, including:

the control unit 104 is further configured to record a logic value of a case that whether each phase current sampling module has a fault, and obtain a table corresponding to the logic value of the case that each phase current sampling module has a fault, and record the table as a logic table.

Specifically, x, y and z are used to represent a, b and c three-phase fault states respectively, the value is 0 or 1, and the value represents that the current sensor is normal or abnormal respectively, so as to indicate the execution direction of logic judgment. Wherein, when the values of x, y and z are 1, the current sensor of the corresponding phase is abnormal. And when the values of x, y and z are 0, the current sensor of the corresponding phase is normal.

Obtaining a measured value i of the alpha-axis stator current component according to the earlier stage_α ^I,II,IIIAnd an instruction value i_α ^*I,II,IIIAnd calculating the deviation value delta of the two current sensors and judging the fault information of the three current sensors.

judgment 1: if delta₁|＞ε₁Then i is_α ^IIn an abnormal state, the a-phase current sensor fails, and x is set to 1. Whereas if delta₁|＜ε₁Then i is_α ^INormally, the phase a current sensor is normal, and x is set to 0.

And (3) judging: if delta₂|＞ε₂Then i is_α ^IIIn case of an abnormality, the b-phase current sensor fails, and y is set to 1. Whereas if delta₂|＜ε₂Then i is_α ^IINormally, the b-phase current sensor is normal, and let y be 0.

And 3, judgment: if delta₃|＞ε₃Then i is_α ^IIIIn case of an abnormality, the c-phase current sensor fails, and z is set to 1. Whereas if delta₃|＜ε₃Then i is_α ^IIINormally, the c-phase current sensor is normal, and z is equal to 0.

The control unit 104 is further specifically configured to determine the number of phases of the current sampling module having a fault condition in the three-phase current sampling modules according to the logic value of whether the fault condition occurs in the three-phase current sampling module.

The control unit 104 is further configured to, if the number of phases of the current sampling module in which the fault condition has occurred in the three-phase current sampling module is one phase, perform fault-tolerant processing on the measured value of the failed one-phase current sampling module according to a first fault-tolerant processing manner, and then control the operation condition of the motor.

In some embodiments, the control unit 104, in a first fault-tolerant processing manner, performs fault-tolerant processing on the measurement value of the failed one-phase current sampling module, including: the control unit 104 is further specifically configured to determine the current values of the α and β axes and the value of the electrical angle corresponding to the logic value of the three-phase current sampling module in the event of a fault according to a first correspondence relationship between the set logic value of the three-phase current sampling module in the event of a fault and the set current values of the α and β axes and the set value of the electrical angle.

Specifically, the values of the α and β axes and the electrical angle at that time are selected appropriately by the different states of the x, y, and z values in table 1.

Table 1: fault tolerant system judgment table

x

y

z

Phase a

Phase b

c phase

Alpha axis

Beta axis

Electric angle

0

Is normal

i_α ^I

i_β ^I

θ

1

0

Fault of

Is normal

i_α ^II

i_β ^II

θ-120

0

1

0

Is normal

Fault of

Is normal

i_α ^III

i_β ^III

θ+120

0

1

Is normal

Fault of

i_α ^I

i_β ^I

θ

The control unit 104 is specifically configured to, if the number of phases of a current sampling module in which a fault condition has occurred in a three-phase current sampling module is two or three, perform fault-tolerant processing on the measured values of the current sampling modules in which more than two phases of the fault condition have occurred in a second fault-tolerant processing manner, and then control the operating condition of the motor.

Specifically, a logic judgment scheme is constructed through different states of x, y and z values so as to select proper alpha and beta axis currents. In the coordinate systems I, II and III, when the stator current component is converted from an alpha beta coordinate system to a dq coordinate system, the selected electrical angles are theta, theta-120 and theta +120 respectively.

When less than two of the three current sensors have faults, namely less than two variables of x, y and z are equal to 1, a first fault-tolerant processing mode is executed. Otherwise, when more than or equal to two of the three current sensors have faults, namely more than or equal to two variables in x, y and z are equal to 1, executing a second fault-tolerant processing mode.

Thus, the current obtained by the three-phase current sensor is subjected to Clark conversion to obtain a current measured value of an alpha axis, the current command values of the d and q axes are subjected to Park inverse conversion to obtain a current command value of the alpha axis, the measured value and the command value are subjected to difference to obtain a deviation delta, and the fault information of the three current sensors is determined by judging the deviation value.

In some embodiments, further comprising: and an observation unit. An observation unit, such as the adaptive back-stepping observer shown in fig. 2.

The control unit 104, according to a second fault-tolerant processing mode, performs fault-tolerant processing on the measurement values of the current sampling modules with more than two phases having faults, including:

the control unit 104 is further specifically configured to perform, by the observation unit, a rotation speed estimation according to the rotation speed of the motor and the d-axis and q-axis voltages to obtain estimated values of d-axis and q-axis currents.

The control unit 104 is specifically further configured to perform Park inverse transformation on the estimated values of the d-axis current and the q-axis current in three coordinate systems, so as to obtain estimated values of α -axis current and β -axis current.

The control unit 104 is further specifically configured to determine, if the two-phase current sampling module fails, an α -axis current value and an electrical angle value corresponding to the logical value of the three-phase current sampling module that fails, according to a second correspondence relationship between the set logical value of whether the three-phase current sampling module fails and the α -axis set current value and the electrical angle set value. And selecting an estimated value of the beta axis current in the estimated values of the alpha axis current and the beta axis current as a current value of the beta axis corresponding to a logic value of whether the three-phase current sampling module has a fault condition.

The control unit 104 is specifically configured to select estimated values of α and β axis currents as α and β axis current values corresponding to a logical value of whether the three-phase current sampling module fails if the three-phase current sampling module fails. And determining the value of the electrical angle corresponding to the logical value of the three-phase current sampling module whether the fault condition occurs according to a second corresponding relation between the set logical value of the three-phase current sampling module whether the fault condition occurs and the set current value of the alpha axis and the set value of the electrical angle.

Specifically, estimated currents of the α and β axes are acquired by an adaptive back-stepping observer.

Fig. 6 is a schematic structural diagram of an embodiment of the adaptive back-stepping observer. Designing a self-adaptive backstepping observer to adjust the rotating speed w of the motor_rAnd d, q-axis voltages u_d ^*And u_q ^*As an input, the d and q axis currents are estimated by converging the rotation speed estimation deviation to 0

And

to pair

Respectively performing the above three coordinate systems I, II and III to obtain the estimated values of the alpha and beta axis currents

And

the specific implementation is shown in fig. 6. The values of the alpha and beta axes and the value of the electrical angle at the moment are selected by different states of the values of x, y and z in the table 2.

Table 2: fault tolerant system judgment table

For example, the first case: xyz are 1, 1 and 0, respectively. This situation indicates that both the x-phase and y-phase current sensors fail, and only the C-phase current sensor is normal, so the coordinate system is chosen to be oriented according to the C-phase of the stator, i.e. coordinate system III, and the α -axis current is i_α ^III. At the moment, the observer starts, and the estimated currents of d and q axes are obtained through the observer

And

carrying out Park inverse transformation under a coordinate system III to obtain alpha and beta axis current estimation values

And

at this time, select

As a beta axis current. Final α -axis current of i_α ^IIIBeta axis current of

The electrical angle varies according to the selected coordinate system, and the coordinate systems can be added to tables 1 and 2, and the examples shown in tables 1 and 2 can be specifically referred to.

Correspondingly, the control unit 104, when one or more of the three-phase current sampling modules fails, performs fault-tolerant processing on the measured value of the failed one or more current sampling modules, and then controls the operation of the motor, including: obtaining i through Park conversion according to the alpha and beta axis current values and the electrical angle_dAnd i_qAnd the current feedback is used as d-axis and q-axis current feedback, and enters a current closed-loop control system to drive a motor to normally operate.

Therefore, the measured values of the three-phase current sensors are monitored and compared, and when the current sensors with the lower two phases have faults, the alpha and beta axis currents can be properly selected. When any two phases have faults, the observer is started, monitoring is carried out according to the d-axis voltage, the q-axis voltage and the rotating speed, more accurate beta-axis current is estimated and predicted, and the alpha-axis current only needs to be selected appropriately. When the three-phase current sensors are in fault, the alpha and beta axis currents obtained by an observer are completely used. And then the obtained alpha and beta axis current values are sent into a control loop, so that the motor can normally run.

When more than two phases of current sensors have faults, current estimation needs to be carried out through the self-adaptive back-stepping observer. Through a fault detection scheme of the current sampling circuit and a system logic architecture of fault-tolerant control, fault diagnosis of a three-phase current sensor in a motor driving system (such as a permanent magnet synchronous motor driving system) can be effectively realized, a fault phase can be accurately judged, the stability of the motor driving system (such as the permanent magnet synchronous motor driving system) is maintained, and the method has high feasibility and reliability.

In the related scheme, only which current sensor fails is judged, and most of the current sensors do not have a fault-tolerant control part. According to the scheme of the invention, fault-tolerant control is carried out when the current sampling circuit fails, specifically, different fault conditions can be analyzed by combining with actual conditions, and when a plurality of current sensors fail, the currents of the alpha axis and the beta axis are estimated by the state observer so as to obtain the current value required by subsequent control, so that the whole current loop can normally run.

Therefore, according to the scheme of the invention, the sampling values of the three current sensors are obtained, so that each phase of current can be analyzed subsequently. Not only can judge whether single-phase breaks down, but also can judge whether any two-phase or three-phase breaks down. And fault-tolerant control processing is carried out according to the state of three-phase fault, so that the scheme is more reasonable. When any two-phase or three-phase current sensor fails, the self-adaptive back-pushing observer is used for observing related parameters and obtaining estimated values of alpha and beta axis currents, namely when a plurality of current sensors fail, the servo driver can continue to drive the motor to operate for a period of time, and the motor cannot stop working immediately. After the three-phase current is detected to have a fault, the self-adaptive back-stepping observer estimates the current so as to carry out fault-tolerant control and enable the motor to normally operate. Of course, in the case where the safety and maintainability are low, the two-phase current sensor may be used to detect the state of the two-phase current sensor and perform the same fault-tolerant control.

In some embodiments, further comprising: and the reminding unit is a voice broadcaster or a display and the like.

The reminding unit is configured to remind whether the three-phase current sampling module has a fault condition.

Specifically, when the current sensor fails, the state information of x, y and z is uploaded to a display panel of the servo driver, and a user is prompted to which phase current sensor of the servo driver fails, so that the sensor can be replaced in time. The display information is 100, 010, 001, 110, 101, 011 and 111, and the a, b and c phase fault information can be known from table 1 and table 2. By adding the fault alarm display device, when a certain phase current sensor has a fault, the fault alarm display device can display the fault on the driver so as to inform a user of timely replacement. That is to say, when a current sensor has a fault, the scheme of the invention can display the fault information of the current sensor of which phase, so that a user can find and replace the current sensor in time.

According to the scheme of the invention, when any one phase of the three-phase current sensors fails, the corresponding sensor is uploaded to the display screen of the driver to inform a user that the relevant current sensor fails, so that the current sensor can be replaced in time. Thus, the device can be prevented from being damaged due to the fault of the current sampling circuit by detecting the fault of the current sampling circuit and displaying the fault information.

For example: when a certain phase current sensor breaks down, the acquired current value is inaccurate or has larger deviation, and if the acquired current value is sent into a motor control current ring at the moment, the motor is certainly damaged. Therefore, when a certain phase current sensor is judged to have a fault, the fault-tolerant control scheme adopted by the scheme of the invention is immediately adopted, and an accurate current value is sent into a control loop to control the normal operation of the motor.

By adopting the technical scheme of the embodiment, the three current sensors are used for current sampling, three different axis-oriented coordinate systems are established, the fault information of the three current sensors is judged according to the comparison between the measured value and the command value of the alpha axis stator current component in the three different axis-oriented coordinate systems, and when more than two current sensors have faults, the estimated current is used for replacing the measured current to carry out motor driving control so as to ensure that the motor stably runs when the faults occur. Therefore, current sampling is carried out by using the three current sensors, and fault diagnosis and fault-tolerant control are carried out on the three current sensors so as to ensure that the motor stably runs when a fault occurs.

According to an embodiment of the present invention, there is also provided a motor corresponding to the control device of the motor drive system. The motor may include: the control device of the motor drive system described above.

Since the processes and functions implemented by the motor of this embodiment substantially correspond to the embodiments, principles and examples of the foregoing devices, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.

By adopting the technical scheme of the invention, the three current sensors are used for current sampling, three different axis oriented coordinate systems are established, the fault information of the three current sensors is judged according to the comparison of the measured value and the instruction value of the alpha axis stator current component under the three different axis oriented coordinate systems, and when more than two current sensors have faults, the estimated current is used for replacing the measured current to carry out motor driving control, so that the stable operation of the motor when the faults occur is ensured, the fault diagnosis and the accurate judgment of the fault phase of the three-phase current sensor in the motor driving system can be effectively realized, and the stability of the motor driving system is maintained.

According to an embodiment of the present invention, there is also provided a control method of a motor driving system corresponding to a motor, as shown in fig. 7, which is a schematic flow chart of an embodiment of the method of the present invention. The motor drive system includes: and (4) current loops. The control method of the motor drive system includes: step S110 to step S140.

In step S110, with the motor running, three-phase current of the motor is sampled by a three-phase current sampling module, for example, U, V, W three-phase current of the motor is sampled, and a measured value of the three-phase current of the motor is obtained. The sampling unit 102 includes: and a three-phase current sampling module. A three-phase current sampling module, such as a three-phase current sensor. A control unit 104, such as the fault tolerant control portion shown in fig. 2. The motor comprises a motor, a phase current sampling module and a phase current sampling module, wherein the phase current sampling module is used for sampling a phase current of the motor under the condition that the motor runs to obtain the currentA measurement of a phase current of one phase of the machine. For example: when the motor runs, the U, V, W-phase current of the motor is respectively sampled by the three current sensors to obtain the corresponding current value i_a、i_b、i_c。i_aCurrent value, i, of U-phase current of motor_bCurrent value, i, of the V-phase current of the motor_cThe current value of the W-phase current of the motor. In the related art, two current sensors are basically used for current sampling. The scheme of the invention uses three current sensors to sample the current, and is used in places with higher requirements on precision and reliability.

In step S120, a coordinate system with three different axial orientations is established by the control unit 104, and coordinate transformation is performed on the measured value and the command value of the three-phase current of the motor in the coordinate system with three different axial orientations, so as to obtain the measured value and the command value of the α -axis stator current component in the coordinate system with three different axial orientations. And the number of the first and second groups,

in some embodiments, in step S120, a specific process of establishing three coordinate systems with different axial orientations by the control unit 104, performing coordinate transformation on the measured values and the command values of the three-phase currents of the motor in the three coordinate systems with different axial orientations, and obtaining the measured values and the command values of the α -axis stator current components in the three coordinate systems with different axial orientations is described in the following exemplary description.

With reference to the flowchart of fig. 8, an embodiment of coordinate transformation performed on the measured values and the command values of the three-phase currents of the motor in the coordinate systems with three different axial orientations is further described, where the specific process of coordinate transformation performed on the measured values and the command values of the three-phase currents of the motor in the step S120 in the coordinate systems with three different axial orientations includes: step S210 to step S230.

Step S210, establishing three coordinate systems according to the phase a orientation, the phase b orientation and the phase c orientation respectively to obtain a first coordinate system, a second coordinate system and a third coordinate system. A first coordinate system, such as coordinate system I. A second coordinate system, such as coordinate system II. A third coordinate system, such as coordinate system III.

Step S220, carrying out Clark transformation on the measured values of the three-phase current of the motor under three coordinate systems with different axial orientations to obtain measured values of the current components of the alpha and beta axial stators, and selecting the measured value of the current component of the alpha axial stator.

And step S230, performing Park inverse transformation on the instruction values of the currents of the d axis and the q axis under three coordinate systems with different axis orientations to obtain the instruction values of the stator current components of the alpha axis and the beta axis, and selecting the instruction value of the stator current component of the alpha axis.

Fig. 3 is a schematic view of a stator a oriented coordinate system I, fig. 4 is a schematic view of a stator b oriented coordinate system II, and fig. 5 is a schematic view of a stator c oriented coordinate system III. Establishing three coordinate systems I, II and III (shown in figures 3, 4 and 5) according to the phase orientation a, the phase orientation b and the phase orientation c respectively, and obtaining the measured value i of the stator current component of the axis alpha and the axis beta through Clark transformation_α ^I,II,IIIAnd i_β ^I,II,III. At the same time, according to the current commands i of d and q axes_d ^*And i_q ^*Obtaining command values i of the stator current components of the alpha and beta axes through Park inverse transformation_α ^*I,II,IIIAnd i_β ^*I,II,III。

in the formula (1) and the formula (2), θ is an angle between the d axis and the a axis in the synchronous rotation coordinate system (i.e. dq coordinate system), i_a、i_bOf phase a, b currents measured by current sensorsCurrent value, i_d ^*、i_q ^*The command values are d and q-axis currents. i.e. i_α ^I、i_β ^IIs measured value I of alpha and beta axis current in coordinate system I (namely alpha and beta coordinate system)_α ^*I、i_β ^*IThe command values are α and β axis currents.

In step S130, the control unit 104 compares the measured value and the command value of the α -axis stator current component in the three coordinate systems oriented along different axes to determine whether one or more of the three-phase current sampling modules have a fault. And the number of the first and second groups,

In step S130, the control unit 104 compares the measured value and the command value of the α -axis stator current component in the three coordinate systems oriented along different axes, and determines whether there is a specific process in which more than one phase of current sampling module fails in the three-phase current sampling module, as shown in the following exemplary description.

With reference to the schematic flow chart of an embodiment of determining whether one or more than one phase of current sampling modules in the three-phase current sampling modules fails in the method of the present invention shown in fig. 9, a specific process of determining whether one or more than one phase of current sampling modules in the three-phase current sampling modules fails in step S130 is further described, which includes: step S310 to step S340.

Step S310, based on the measured values and the command values of the alpha-axis stator current components in the three coordinate systems with different axial orientations, determining whether the absolute values of the deviation values of the measured values and the command values of the alpha-axis stator current components in each coordinate system are larger than the set threshold value in the coordinate system.

In step S320, if the absolute value of the deviation between the measured value and the command value of the α -axis stator current component in the first coordinate system is greater than the set threshold in the first coordinate system, it is determined that the a-phase current sampling module fails. Otherwise, the a-phase current sampling module is determined not to be in fault.

In step S330, if the absolute value of the deviation between the measured value and the command value of the α -axis stator current component in the second coordinate system is greater than the set threshold in the second coordinate system, it is determined that the b-phase current sampling module fails. Otherwise, determining that the b-phase current sampling module is not in fault.

In step S340, if the absolute value of the deviation value between the measured value and the command value of the α -axis stator current component in the third coordinate system is greater than the set threshold in the third coordinate system, it is determined that the c-phase current sampling module fails. Otherwise, determining that the c-phase current sampling module is not in fault.

Specifically, a measured value i of the alpha-axis stator current component is obtained according to the previous period_α ^I,II,IIIAnd an instruction value i_α ^*I,II,IIIAnd calculating the deviation value delta of the two current sensors and judging the fault information of the three current sensors. Epsilon₁、ε₂And epsilon₃For the safety threshold, the threshold size may be set according to the actual use condition.

And (6) judging: if delta₂|＞ε₂Then i is_α ^IIAbnormal, b-phase current sensorAnd generating a fault. Whereas if delta₂|＜ε₂Then i is_α ^IINormally, the b-phase current normal sensor is normal.

In step S140, when one or more of the three-phase current sampling modules fails, the control unit 104 performs fault tolerance on the measured value of the failed one or more current sampling modules, and then controls the operation of the motor.

FIG. 2 is a schematic diagram of an embodiment of a fault-tolerant servo control system (i.e., a servo system with current sampling fault detection and fault-tolerant control). The fault-tolerant servo control system shown in fig. 2 is specifically a current sampling fault detection and fault-tolerant control method, and consists of a Clark transformation part, a Park inverse transformation part, a self-adaptive backstepping observer and a fault-tolerant control part. Wherein, Clark transformation is to transform abc into a stationary alpha beta coordinate system. And performing Park inverse transformation, namely transforming abc into a rotating dq coordinate system.

Thus, the scheme of the invention establishes three coordinate systems with different axial orientations through a control method of a motor driving system, such as a servo system with current sampling fault detection and fault-tolerant control, compares command values (namely given values) and measured values of alpha-axis stator current components in the three coordinate systems with different axial orientations, and judges fault information of three current sensors. A logic judgment mechanism is designed according to the three coordinate systems, and when a fault occurs, the proper estimated current is used for replacing the measured current to carry out feedback so as to reconstruct a system, so that the stable operation of the motor is ensured when the fault occurs.

In some embodiments, in step S140, when one or more of the three-phase current sampling modules fails, the control unit 104 performs a specific process of performing fault tolerance on the measurement value of the failed one or more phase current sampling modules and then controlling the operation of the motor, which is described in the following exemplary description.

Referring to fig. 10, a flowchart of an embodiment of performing fault tolerance processing on the measurement value of the current sampling module of the one or more phases with the fault in the method of the present invention is further described, where the specific process of performing fault tolerance processing on the measurement value of the current sampling module of the one or more phases with the fault in step S140 includes: step S410 to step S440.

Step S410, recording the logic value of the condition whether each phase current sampling module has a fault, and obtaining a table corresponding to the logic value of the condition whether the three-phase current sampling module has a fault, and recording the table as a logic table.

judgment 1: if delta₁|＞ε₁Then i is_α ^IAbnormal, a-phase currentThe sensor is out of order, and x is 1. Whereas if delta₁|＜ε₁Then i is_α ^INormally, the phase a current sensor is normal, and x is set to 0.

Step S420, determining the number of phases of the current sampling module having a fault condition in the three-phase current sampling modules according to the logic value of whether the three-phase current sampling module has a fault condition.

Step S430, if the phase number of the current sampling module which has a fault condition in the three-phase current sampling module is one phase, the measured value of the failed one-phase current sampling module is subjected to fault-tolerant processing according to a first fault-tolerant processing mode, and then the running condition of the motor is controlled.

In some embodiments, the specific process of performing fault-tolerant processing on the measurement value of the failed one-phase current sampling module in the first fault-tolerant processing manner by the control unit 104 in step S340 includes: and determining the current values of the alpha shaft and the beta shaft and the value of the electrical angle corresponding to the logic value of the fault condition of the three-phase current sampling module according to the first corresponding relation between the set logic value of the fault condition of the three-phase current sampling module and the set current values of the alpha shaft and the beta shaft and the set value of the electrical angle.

Table 1: fault tolerant system judgment table

x

y

z

Phase a

Phase b

c phase

Alpha axis

Beta axis

Electric angle

0

Is normal

i_α ^I

i_β ^I

θ

1

0

Fault of

Is normal

i_α ^II

i_β ^II

θ-120

0

1

0

Is normal

Fault of

Is normal

i_α ^III

i_β ^III

θ+120

0

1

Is normal

Fault of

i_α ^I

i_β ^I

θ

Step S440, if the number of phases of the current sampling module having a fault condition in the three-phase current sampling module is two or three, performing fault-tolerant processing on the measured value of the current sampling module having more than two phases of the fault condition according to a second fault-tolerant processing mode, and then controlling the operation condition of the motor.

In some embodiments, the specific process of fault-tolerant processing is performed on the measured values of the current sampling modules of two or more phases with faults in step S440 by the control unit 104 in the second fault-tolerant processing manner, which is described in the following exemplary description.

Referring to fig. 11, a schematic flow chart of an embodiment of performing fault tolerance processing on the measurement values of the two or more failed current sampling modules in the method of the present invention further illustrates a specific process of performing fault tolerance processing on the measurement values of the two or more failed current sampling modules in step S440, including: step S510 to step S540.

And step S510, estimating the rotating speed through an observation unit according to the rotating speed of the motor and the voltages of the d axis and the q axis to obtain estimated values of the currents of the d axis and the q axis. An observation unit, such as the adaptive back-stepping observer shown in fig. 2.

And step S520, respectively carrying out Park inverse transformation on the estimated values of the d-axis current and the q-axis current under three coordinate systems to obtain estimated values of the alpha-axis current and the beta-axis current.

Step S530, if the two-phase current sampling module fails, determining an α -axis current value and an electrical angle value corresponding to the logical value of the three-phase current sampling module that indicates whether the three-phase current sampling module fails according to a second correspondence relationship between the set logical value of the three-phase current sampling module that indicates whether the three-phase current sampling module fails and the set current value of the α -axis and the set value of the electrical angle. And selecting an estimated value of the beta axis current in the estimated values of the alpha axis current and the beta axis current as a current value of the beta axis corresponding to a logic value of whether the three-phase current sampling module has a fault condition.

And step S540, if the three-phase current sampling module fails, selecting the estimated values of the alpha and beta axis currents as the current values of the alpha and beta axes corresponding to the logic values of whether the three-phase current sampling module fails. And determining the value of the electrical angle corresponding to the logical value of the three-phase current sampling module whether the fault condition occurs according to a second corresponding relation between the set logical value of the three-phase current sampling module whether the fault condition occurs and the set current value of the alpha axis and the set value of the electrical angle.

And

to pair

And

the specific implementation is shown in fig. 6. Through different states of x, y and z values in the table 2, the proper alpha and beta axis current values and the current moment are selectedThe value of the electrical angle.

Table 2: fault tolerant system judgment table

In some embodiments, further comprising: and the reminding unit is used for reminding whether the three-phase current sampling module has a fault or not. And the reminding unit is a voice broadcaster or a display and the like.

Specifically, when the current sensor fails, the state information of x, y and z is uploaded to a display panel of the servo driver, and a user is prompted to which phase current sensor of the servo driver fails, so that the sensor can be replaced in time. The display information is 100, 010, 001, 110, 101, 011 and 111, and the a, b and c phase fault information can be known from table 1 and table 2. By adding the fault alarm display method, when a certain phase current sensor has a fault, the fault alarm display method can display the fault on the driver so as to inform a user of timely replacement. That is to say, when a current sensor has a fault, the scheme of the invention can display the fault information of the current sensor of which phase, so that a user can find and replace the current sensor in time.

Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles and examples of the motor, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment, which is not described herein.

By adopting the technical scheme of the invention, three current sensors are used for current sampling, three different axis oriented coordinate systems are established, fault information of the three current sensors is judged according to comparison between measured values and instruction values of alpha axis stator current components in the three different axis oriented coordinate systems, and when more than two current sensors have faults, estimated current is used for replacing measured current to carry out motor drive control so as to ensure that the motor stably runs when the faults occur, and the fault information is detected and displayed through the faults of the current sampling circuit, so that the device damage caused by the faults of the current sampling circuit can be prevented.

In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A control device of a motor drive system, characterized by comprising: a sampling unit and a control unit; the sampling unit includes: a three-phase current sampling module; wherein the content of the first and second substances,

the three-phase current sampling module is configured to sample three-phase current of the motor under the condition that the motor is operated, so as to obtain a measured value of the three-phase current of the motor;

the control unit is configured to establish three coordinate systems with different axial orientations, and perform coordinate transformation on the measured values and the instruction values of the three-phase current of the motor under the three coordinate systems with different axial orientations to obtain the measured values and the instruction values of the alpha-axis stator current components under the three coordinate systems with different axial orientations; and the number of the first and second groups,

comparing measured values and command values of the alpha-axis stator current components in three coordinate systems with different axial orientations to determine whether more than one phase of current sampling modules in the three-phase current sampling modules have faults; and the number of the first and second groups,

and under the condition that more than one phase of current sampling modules in the three-phase current sampling modules have faults, carrying out fault-tolerant processing on the measured values of the faulted more than one phase of current sampling modules, and then controlling the running condition of the motor.

2. The control device of a motor drive system according to claim 1, wherein the control unit establishes three coordinate systems with different axial orientations, performs coordinate transformation on the measured values and the command values of the three-phase currents of the motor in the three coordinate systems with different axial orientations, and obtains the measured values and the command values of the α -axis stator current components in the three coordinate systems with different axial orientations, and includes:

establishing three coordinate systems according to the phase a orientation, the phase b orientation and the phase c orientation respectively to obtain a first coordinate system, a second coordinate system and a third coordinate system;

performing Clark transformation on the measured values of the three-phase current of the motor under three coordinate systems with different axial orientations to obtain measured values of the current components of the alpha and beta axial stators, and selecting the measured value of the current component of the alpha axial stator;

and carrying out Park inverse transformation on the instruction values of the currents of the d axis and the q axis under three coordinate systems with different axis orientations to obtain the instruction values of the stator current components of the alpha axis and the beta axis, and selecting the instruction value of the stator current component of the alpha axis.

3. The control device of a motor drive system according to claim 1, wherein the three coordinate systems oriented in different axes comprise: a first coordinate system, a second coordinate system and a third coordinate system are respectively established according to the phase a orientation, the phase b orientation and the phase c orientation;

the control unit compares the measured value and the command value of the alpha-axis stator current component under three coordinate systems with different axial orientations to determine whether more than one phase of current sampling modules in the three-phase current sampling modules have faults or not, and comprises the following steps:

determining whether the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in each coordinate system is greater than the set threshold value in the coordinate system or not based on the measured value and the command value of the alpha-axis stator current component in the three coordinate systems with different axial orientations;

if the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in the first coordinate system is larger than the set threshold value in the first coordinate system, determining that the a-phase current sampling module has a fault; otherwise, determining that the a-phase current sampling module is not in fault;

if the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in the second coordinate system is larger than the set threshold value in the second coordinate system, determining that the b-phase current sampling module has a fault; otherwise, determining that the b-phase current sampling module is not in fault;

if the absolute value of the deviation value of the measured value and the command value of the alpha-axis stator current component in the third coordinate system is larger than the set threshold value in the third coordinate system, determining that the c-phase current sampling module fails; otherwise, determining that the c-phase current sampling module is not in fault.

4. The control device of a motor drive system according to any one of claims 1 to 3, wherein the control unit controls the operation of the motor after performing fault-tolerant processing on the measurement value of one or more failed current sampling modules when one or more failed current sampling modules of the three-phase current sampling modules have failed, and the control device includes:

recording the logic value of the condition whether each phase of current sampling module has a fault or not;

determining the phase number of the current sampling module which has a fault condition in the three-phase current sampling module according to the logic value of whether the three-phase current sampling module has the fault condition;

if the phase number of the current sampling module which has a fault condition in the three-phase current sampling module is one phase, carrying out fault-tolerant processing on the measured value of the faulted one-phase current sampling module according to a first fault-tolerant processing mode, and then controlling the running condition of the motor;

if the phase number of the current sampling module with the fault condition in the three-phase current sampling module is two-phase or three-phase, the measured value of the current sampling module with more than two phases with the fault is subjected to fault-tolerant processing according to a second fault-tolerant processing mode, and then the running condition of the motor is controlled.

5. The control apparatus of a motor drive system according to claim 4, wherein said control unit fault-tolerant processes the measured values of the failed one-phase current sampling module in a first fault-tolerant processing manner, comprising:

and determining the current values of the alpha shaft and the beta shaft and the value of the electrical angle corresponding to the logic value of the fault condition of the three-phase current sampling module according to the first corresponding relation between the set logic value of the fault condition of the three-phase current sampling module and the set current values of the alpha shaft and the beta shaft and the set value of the electrical angle.

6. The control device of the motor drive system according to claim 4, characterized by further comprising: an observation unit;

the control unit carries out fault-tolerant processing on the measured value of the current sampling module with more than two phases with faults according to a second fault-tolerant processing mode, and the fault-tolerant processing method comprises the following steps:

estimating the rotating speed through the observation unit according to the rotating speed of the motor and the d-axis and q-axis voltages to obtain estimated values of d-axis and q-axis currents;

carrying out Park inverse transformation on the estimated values of the d-axis current and the q-axis current respectively under three coordinate systems to obtain estimated values of the alpha-axis current and the beta-axis current;

if the two-phase current sampling module has a fault, determining the current value of the alpha axis and the value of the electrical angle corresponding to the logic value of the three-phase current sampling module if the three-phase current sampling module has the fault according to a second corresponding relation between the set logic value of the three-phase current sampling module if the three-phase current sampling module has the fault and the set current value of the alpha axis and the set value of the electrical angle; selecting an estimated value of the beta axis current in the estimated values of the alpha axis current and the beta axis current as a current value of the beta axis corresponding to a logic value of whether the three-phase current sampling module has a fault condition;

if the three-phase current sampling module fails, selecting estimated values of alpha and beta axis currents as current values of alpha and beta axes corresponding to the logical value of whether the three-phase current sampling module fails; and determining the value of the electrical angle corresponding to the logical value of the three-phase current sampling module whether the fault condition occurs according to a second corresponding relation between the set logical value of the three-phase current sampling module whether the fault condition occurs and the set current value of the alpha axis and the set value of the electrical angle.

7. The control device of a motor drive system according to any one of claims 1 to 3, characterized by further comprising: a reminding unit;

8. An electric machine, comprising: the control device of the motor drive system according to any one of claims 1 to 7.

9. A control method of a motor drive system, characterized by comprising:

sampling three-phase current of the motor through a three-phase current sampling module under the condition that the motor runs to obtain a measured value of the three-phase current of the motor;

establishing three coordinate systems with different axial orientations through a control unit, and performing coordinate transformation on the measured values and the instruction values of the three-phase current of the motor under the three coordinate systems with different axial orientations to obtain the measured values and the instruction values of the alpha-axis stator current components under the three coordinate systems with different axial orientations; and the number of the first and second groups,

10. The control method of a motor drive system according to claim 9, wherein three coordinate systems with different axial orientations are established by a control unit, and coordinate transformation is performed on the measured values and command values of the three-phase current of the motor in the three coordinate systems with different axial orientations to obtain the measured values and command values of the stator current component of the α axis in the three coordinate systems with different axial orientations, including:

11. The control method of a motor drive system according to claim 9, wherein the three coordinate systems oriented in different axes include: a first coordinate system, a second coordinate system and a third coordinate system are respectively established according to the phase a orientation, the phase b orientation and the phase c orientation;

through the control unit, according to the measured value and the instruction value of alpha axle stator current component under the directional coordinate system of three disalignment, confirm whether have more than one looks current sampling module in the three-phase current sampling module to break down, include:

12. The method for controlling a motor drive system according to any one of claims 9 to 11, wherein when one or more of the three-phase current sampling modules has a fault, the control unit performs fault-tolerant processing on the measurement value of the faulty one or more current sampling modules and then controls the operation of the motor, and the method includes:

13. The method for controlling a motor drive system according to claim 12, wherein the fault-tolerant processing of the measured values of the failed one-phase current sampling module by the control unit in a first fault-tolerant processing manner comprises:

14. The method for controlling a motor drive system according to claim 12, wherein the fault-tolerant processing of the measured values of the two or more faulty current sampling modules by the control unit in the second fault-tolerant processing mode includes:

estimating the rotating speed through an observation unit according to the rotating speed of the motor and the d-axis and q-axis voltages to obtain estimated values of d-axis and q-axis currents;

15. The control method of a motor drive system according to any one of claims 9 to 11, characterized by further comprising:

and the reminding unit is used for reminding whether the three-phase current sampling module has a fault or not.