CN111448750B - Fault tolerant permanent magnet DC motor driver - Google Patents
Fault tolerant permanent magnet DC motor driver Download PDFInfo
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- CN111448750B CN111448750B CN201780097310.1A CN201780097310A CN111448750B CN 111448750 B CN111448750 B CN 111448750B CN 201780097310 A CN201780097310 A CN 201780097310A CN 111448750 B CN111448750 B CN 111448750B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
- B62D5/0484—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures for reaction to failures, e.g. limp home
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/08—Arrangements for controlling the speed or torque of a single motor
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Abstract
A solution for generating an output torque of a multi-winding PMDC motor is described. An example method includes generating, by a current controller, a first voltage command for a first winding set of a plurality of winding sets of a PMDC motor, the first winding set generating a first current in response to the first voltage command. The method also includes generating, by the current controller, a second voltage command for a second set of windings of the PMDC motor, the second set of windings generating a second current in response to the second voltage command. The method also includes generating, by the PMDC motor, an output torque based on the first current and the second current.
Description
Background
The present application relates generally to permanent magnet direct current motor (PMDC motor) drives and, more particularly, to fault tolerant operation of PMDC motor drives.
The need for fault tolerant operation of safety critical systems such as those involved in automotive subsystems including Electric Power Steering (EPS) and Automatic Driving Assistance Systems (ADAS) is increasing. This requirement triggers the introduction of redundancy in the electromechanical motion control system, enabling improved fault tolerance and thus fail safe operation. An electric drive system typically includes an electric motor, one or more power converters and sensors, and other components for facilitating operation of the motion control system.
It is therefore desirable to introduce redundancy in the drive system to improve the fault tolerance of the automotive subsystems and other components using such electric drive systems.
Disclosure of Invention
In accordance with one or more embodiments, a system includes a Permanent Magnet Direct Current (PMDC) motor including a plurality of winding sets. A first winding set of the plurality of winding sets includes a first pair of poles, a first pair of brushes, and a first winding. Further, a second winding set of the plurality of winding sets includes a second pair of poles, a second pair of brushes, and a second winding. The system also includes a controller that causes the PMDC motor to generate a predetermined amount of torque by applying a first voltage command to a first winding set, wherein the first winding set generates a first current in response to the first voltage command, and that causes the PMDC motor to generate a predetermined amount of torque by applying a second voltage command to a second winding set, wherein the second winding set generates a second current in response to the second voltage command. The first current and the second current cause the motor to generate a predetermined amount of torque.
In accordance with one or more embodiments, a Permanent Magnet Direct Current (PMDC) motor includes a plurality of winding sets. A first winding set of the plurality of winding sets includes a first pair of poles, a first pair of brushes, and a first winding. A second winding set of the plurality of winding sets includes a second pair of poles, a second pair of brushes, and a second winding. The first winding set generates a first current command in response to a first voltage command from the controller. The second winding set generates a second current command in response to a second voltage command from the controller.
In accordance with one or more embodiments, a method for generating an output torque of a multi-winding PMDC motor includes: a first voltage command is generated by a current controller for a first winding set of a plurality of winding sets of the PMDC motor, wherein the first winding set generates a first current in response to the first voltage command. The method also includes generating, by the current controller, a second voltage command for a second winding set of the plurality of winding sets of the PMDC motor, wherein the second winding set generates a second current in response to the second voltage command. The method also includes generating, by the PMDC motor, an output torque based on the first current and the second current.
These and other advantages and features will become more apparent from the following description taken in conjunction with the accompanying drawings.
Drawings
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the disclosure will become apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is an exemplary embodiment of a vehicle 10 including a steering system;
FIG. 2 depicts a configuration of a PMDC machine according to one or more embodiments;
FIG. 3 depicts another configuration of a PMDC machine according to one or more embodiments;
FIG. 4 depicts an example multi-winding PMDC machine in accordance with one or more embodiments;
FIG. 5 depicts a block diagram of a dual winding PMDC machine using a mathematical model in accordance with one or more embodiments;
FIG. 6 depicts an example multi-winding PMDC machine in accordance with one or more embodiments;
FIG. 7 depicts an example system 700 using a multi-winding PMDC machine in accordance with one or more embodiments;
FIG. 8 depicts an example fault tolerant system in accordance with one or more embodiments; and
fig. 9 illustrates a flowchart of an example method for providing fault tolerance in a PMDC motor control system using a multi-winding PMDC motor in accordance with one or more embodiments.
FIG. 10 depicts an example fault tolerant system architecture in accordance with one or more embodiments.
Detailed Description
The terms "module" and "sub-module" are used herein to refer to one or more processing circuits (e.g., application Specific Integrated Circuits (ASICs), electronic circuits), processors (shared, dedicated, or group) and memory that execute one or more software or firmware programs, combinational logic circuits, and/or other suitable components that provide the described functionality. It is to be appreciated that the sub-modules described below may be combined and/or further partitioned.
Permanent Magnet Direct Current (PMDC) motors are widely used in automotive applications such as electric power assisted steering (EPS) systems. PMDC motors have three main components, namely a stator, a rotor and a commutator. Typically, the stator contains poles, and the rotor is an armature carrying windings. The commutator is attached to brushes and slip rings to allow the machine to mechanically commutate. The machine may be a PMDC motor itself or a system using a PMDC motor, such as an EPS system. The brushes are connected to the phase wire terminals through which a voltage can be applied to the machine. Brushes are generally susceptible to mechanical wear. Mechanical wear may cause the PMDC motor to fail, after which the machine will fail. In EPS system settings, the absence of the PMDC motor may result in the driver losing assistance. In addition to the motor, the power converter circuit and the microcontroller (logic) board for controlling the electric drive system are also prone to failure.
The technical challenges described above are addressed by the technical solutions described herein to facilitate PMDC-based power drive system fault tolerance by including techniques in PMDC machines for introducing redundancy and control architectures involving redundancy in power converters and logic circuits. In addition, the technical scheme also provides an analysis model of the PMDC machine. It should be noted that the various embodiments of the solution described herein use examples of EPS systems, but the solution is also applicable to other settings, such as electric tools, rotor pumps and industrial applications, as well as other situations where PMDC motors are used.
Referring now to the drawings, the technical solution will be described with reference to specific embodiments, but is not limited thereto. FIG. 1 is an exemplary embodiment of a vehicle 10 including a steering system 12. In various embodiments, the steering system 12 includes a steering wheel 14 coupled to a steering shaft system 16, the steering shaft system 16 including a steering column, a countershaft, and necessary joints. In one exemplary embodiment, the steering system 12 is an EPS system that also includes a steering assist unit 18, the steering assist unit 18 being coupled to the steering shaft system 16 of the steering system 12 and to the connecting rods 20, 22 of the vehicle 10. Alternatively, the steering assist unit 18 may couple an upper portion of the steering shaft system 16 with a lower portion of the system. The steering assist unit 18 includes, for example, a rack and pinion steering mechanism (not shown) that may be coupled to a steering actuation motor 19 and gearing by a steering shaft system 16. During operation, as the vehicle operator turns the steering wheel 14, the steering actuation motor 19 provides assistance to move the connecting rods 20, 22, which in turn move the knuckles 24, 26, respectively, that are each coupled to a wheel 28, 30 of the vehicle 10.
As shown in fig. 1, the vehicle 10 also includes various sensors 31, 32, 33, which sensors 31, 32, 33 detect and measure observable conditions of the steering system 12 and/or the vehicle 10. The sensors 31, 32, 33 generate sensor signals based on observable conditions. In one example, the sensor 31 is a torque sensor and is configured to sense an input driver steering wheel torque (HWT) applied to the steering wheel 14 by the driver of the vehicle 10. The torque sensor generates a driver torque signal based thereon. In another example, the sensor 32 is a motor angle and speed sensor and is used to sense the rotational angle and speed of the steering actuation motor 19. In yet another example, the sensor 33 is a steering wheel position sensor and is used to sense the position of the steering wheel 14. Based on this, the sensor 33 generates a steering wheel position signal.
The control module 40 receives one or more sensor signals input from the sensors 31, 32, 33 and may receive other inputs, such as a vehicle speed signal 34. Based on one or more inputs and further based on the steering control system and method of the present disclosure, the control module 40 generates command signals to control the steering actuation motor 19 of the steering system 12. The steering control system and method of the present disclosure applies signal conditioning via the steering assist unit 18 to control various aspects of the steering system 12. Communication with other sub-components of the vehicle 10, such as an Antilock Brake System (ABS) 44, an Electronic Stability Control (ESC) system 46, and other systems (not shown), may be performed using, for example, a Controller Area Network (CAN) bus or other vehicle network known in the art, to exchange signals such as the vehicle speed signal 34.
In one or more examples, the motor 19 is a PMDC motor that is controlled using the techniques described herein.
Fig. 2 depicts a configuration of a PMDC machine in accordance with one or more embodiments. In the illustration, a first view 101 and a second view 102 of the construction of a PMDC machine are depicted. As shown, PMDC machine 100 includes one pole pair (N and S) 110, one brush pair (B1 and B2) 120, six rotor slots (gaps T1-T6 between rotor poles) 130 corresponding to each other, and six commutating segments (1.1-1.2, 2.1-2.2, and 3.1-3.2) 140 with single lap winding 150. Fig. 2 also includes a view of the equivalent circuit 105 of the machine. It should be noted that the technical solution described herein is not limited to a PMDC machine 100 having the configuration shown in fig. 2. Conversely, in other examples, PMDC machine 100 may include additional brush pairs 120, pole pairs 110. Alternatively or additionally, in other examples, PMDC machine 100 may include a different number of rotor slots 130, or a different winding pattern of commutator segments 140.
Fig. 3 depicts another configuration of a PMDC machine in accordance with one or more embodiments. In the illustration, the construction of a PMDC machine is depicted using a first view 201 and a second view 202. PMDC machine 100 includes two pole pairs 110, two brush pairs (B1-B2 and B3-B4) 120, six rotor slots (gaps T1-T6 between rotor poles) 130, and corresponding 12 commutator segments (1.1-1.4, 2.1-2.4, and 3.1-3.4) 140. The windings 150 in the PMDC machine 100 use lap windings.
In both fig. 2 and 3, the PMDC machine 100 does not perform satisfactorily when the brushes fail because the terminals of the PMDC machine 100 bind the brushes 120 together. The solution described herein solves this technical challenge by providing redundancy within PMDC machine 100 by adding multiple winding sets and additional brush pairs 120 within rotor slots 130, as well as terminals individually drawn from each brush pair 120. For example, the redundancy solution may use 2 independent motor drives (i.e., 2 motors, 2 inverters, and 2 microcontrollers). The use of such multiple subsystems incurs additional costs and further requires additional packaging and housing of the assembly. The solution described herein uses a single motor in different ways, for example: (1) A plurality of windings of the motor having a plurality of pairs of brushes are controlled by one microcontroller and a plurality of inverters, (2) a plurality of windings of the motor having a plurality of pairs of brushes are controlled by a plurality of controllers and a plurality of inverters.
The solution described herein facilitates the inclusion of multiple PMDC machines within the same physical stator and rotor structure of a single PMDC machine. This PMDC machine including a plurality of PMDC machines is referred to by the present disclosure as a "multi-winding PMDC machine". Furthermore, the technical solution comprises a control architecture for a multi-winding machine with redundant power converters and logic circuits.
The mathematical model of a single wire wound PMDC machine such as PMDC machine 100 (fig. 2/3) is represented as follows:
T e ＝K e I
wherein V, I and T e Is the terminal voltage, current and electromagnetic torque of the machine, L, R, K e And V bd Is inductance, resistance, voltage (torque) constant, and brush voltage drop. Note that the brush drop term is non-linear and can be expressed as follows.
Wherein V is 0 And I 0 Is a state variable of the brush drop function. Due to variations in temperature and magnetic saturation, machine parameters vary non-linearly with operating conditions.
In a multi-winding PMDC machine, there is additional magnetic (inductive) coupling between the phases. Due to this coupling, the machine model differs from the single wire wound machine described above.
Fig. 4 depicts an example multi-winding PMDC machine in accordance with one or more embodiments. The multi-winding PMDC machine 300 of fig. 4 is a "two-wire wound PMDC machine" having 4 stator poles (i.e., 2 pole pairs) 110, 12 commutation plates 130 and rotor slots, and 4 brushes (2 brush pairs B1-B4) 120. Furthermore, the dual winding PMDC machine 300 comprises a distributed lap winding 150 with a full pitch (diametrical pitch).
Fig. 5 depicts a block diagram of a dual winding PMDC machine using a mathematical model in accordance with one or more embodiments. The view of the dual winding PMDC machine 300 depicts the controller 510 and the PMDC motor 520 whereIn this case, motor 520 includes a double winding. In one or more examples, the controller 510 operates in a feedback control mode. For a dual winding PMDC motor 520, two input voltages (V 1 ) 530a and (V) 2 ) 530b may be based on voltage commands generated by controller 510 (e.g., by a power controller (not shown)). It should be noted that although the voltage command generated by controller 510 is ideally equal to the input voltage (V 1 ) 530a and (V) 2 ) 530b, but in practice these values may be slightly different due to, for example, non-linearities of the power converter circuit.
In addition, since the back electromotive force (ω) of each corresponding winding m ) And the voltage command is modified. The back emf is based on the speed of motor 520. For example, a first back EMF voltage (ω) of a first winding set of motor 520 m ) 532a is based on motor speed and a first back emf (and torque) constant K of the first winding set e1 . Similarly, a second back EMF voltage (ω) of a second winding set of motor 520 m ) 532b is based on the motor speed and a second back emf (and torque) constant K of the second winding e2 。
Due to the brush drop voltage (V bd ) And the voltage commands 530a-530b are further modified. For example, a first voltage (V1) 530a is added to the brush drop voltage of the first winding, a second voltage V 2 Adding the brush drop voltage of the second winding. Based on the inductance and resistance of each winding, the voltage is converted into a current (I 1 ) 540a and (I) 2 ) 540b, and the current further generates a resultant torque (T) from motor 520 e ) 550. Based on the respective constant K of each winding e1 And K e2 Output torque 550 and current I 1 And I 2 Proportional to the ratio. Furthermore, the magnetic coupling (M) between the two windings further affects the current generated by the voltage command.
Due to the additional magnetic coupling between the phases of the dual winding PMDC machine 300, the machine model of the machine 300 differs from the machine model of the single winding machine 100 compared to the single winding PMDC machine 200. For example, a mathematical model for the two-wire wound PMDC machine 300 is given below.
T e ＝K e1 I 1 +K e2 I 2
Wherein M is 12 ＝M 21 =m, representing the inductive coupling between the two phases. Typically, the mutual inductance term (M 12 I 2 And M 21 I 1 ) Random current I 1 And I 2 Nonlinear variation.
The model can be easily extended to n-phase PMDC machines, where n represents the number of windings used (or the number of redundant machines included in a single PMDC machine). A general model of an n-phase motor can be expressed as follows.
T e ＝K e1 I 1 +K e2 I 2 +…+K en I n
Where the mutual inductances are generally designated as different. Note that the mutual inductances of the two sets of windings (e.g., set a and set b) are equal, i.e., M ab ＝M ba . For simplicity, the rest of the description is directed to a double winding machine, which can be extended to general n-phase machines. The voltage-current equation for a two-wire wound machine can be expressed in the form of a transfer matrix (transfer matrix) as follows.
Wherein it is assumed that the two brush drop terms are independent of current in order to generate a transfer matrix representation of the PMDC machine (because the frequency domain representation of the transfer matrix requires a linear time-invariant model in the time domain). Thus, the output current can be expressed as follows according to the input voltage.
Wherein Δ(s) = (L) 1 s+R 1 )(L 2 s+R 2 )-s 2 M 2 ＝(L 1 L 2 -M 2 )s 2 +(L 1 R 2 +L 2 R 1 )s+R 1 R 2 。
When the winding arrangement is symmetrical and the two brush pairs are similar, the model described above can be simplified to assume that the half-machine is identical, i.e. the self-inductance, resistance, voltage constant and brush drop parameters are equal.
Thus, in the dual winding PMDC machine 300, the controller 510 simultaneously generates the output torque 550 using both windings by generating voltage commands to generate the voltages 530a-530b such that the resulting current results in the output torque 550. The controller 510 generates voltage commands 530a-530b based on the output torque 550 to be generated by the motor 520. In the event of a failure of one winding (e.g., the first winding), the corresponding current 540b continues to be generated using the second voltage command 530b on the second winding, resulting in at least a portion of the output torque 550.
Alternatively or additionally, controller 510 generates only a single voltage command to generate an input voltage (e.g., first voltage 530 a) to generate an output torque using only the first winding. In the event of a failure of the first winding, the controller 510 then uses the second winding to generate a second input voltage (V 2 ) 530b, thereby generating an output torque 550.
The above model can be extended to an n-winding PMDC machine (rather than just a double winding), where the controller 510 uses n (n is greater than 2) voltage hits for the n windingsLet V 1 -V n Each voltage command generates a corresponding current I 1 -I n And they together cause the motor to generate an output torque (T e )550。
Fig. 6 depicts an example multi-winding PMDC machine in accordance with one or more embodiments. The multi-winding PMDC machine 600 of fig. 6 includes four PMDC machines having four pole pairs (stators), four brush pairs (B1-B8) 120, 40 commutator segments (1.1-1.4-10.1-10.4) and 10 rotor slots (gaps T1-T10 between rotor poles) 130 for placing the windings 150. Thus, the multi-winding PMDC machine 600 includes multiple (four) windings with multiple brush pairs and terminals, and thus, the PMDC machine 600 effectively includes multiple PMDC machines in the same stator and rotor physical structure. Thus, in the event of a single brush failure, PMDC machine 300 continues to operate with the remaining (normal) terminals. In the example shown, four sets of terminals facilitate fault tolerant operation in the event of a brush failure.
To make the multi-winding PMDC machine 600 fault tolerant by providing redundancy, the multi-winding PMDC machine 600 includes a number of pole pairs 110 in the stator that is greater than or equal to the number of brush pairs 120, and the number of pole pairs 110 is an integer multiple of the number of brush pairs 120. Further, the number of rotor slots 130 for the windings 150 is based on the number of brush pairs 120. Furthermore, in different examples of the multi-winding PMDC machine 600, different winding arrangements may be selected for different purposes. For example, for a two-winding PMDC machine 300 (which is a multi-winding PMDC machine type having two windings), the conductors of the two half-machines may be in half of the rotor or the conductors placed in alternating slots in the outer periphery of the rotor. It should also be noted that the number of redundant machines in a multi-winding PMDC machine is selected based on the application under consideration, including considering the geometry of the machine, to ensure mechanical strength of the machine. It should be noted that the foregoing is a general rule set for implementing one or more embodiments described herein. The technical solutions described herein facilitate the construction of n winding-set PMDC machines (as well as n power converters and n microcontrollers), and there are various ways to construct such PMDC machines using the technical features described herein.
Multiple windingsThe group PMDC machine 600 helps the electric drive continue to provide total power in the event of a failure of a pair of brushes (one winding set)This increases the fault tolerance of the drive system, thereby providing the ability for fail safe operation.
Furthermore, in addition to using a multi-winding PMDC machine, the solutions described herein facilitate additional redundancy by using a control architecture that includes multiple power converters (H-bridges) and/or microcontrollers.
Fig. 7 depicts an example system 700 using a multi-winding PMDC machine in accordance with one or more embodiments. The system 700 comprises a multi-winding PMDC machine 600, the multi-winding PMDC machine 600 comprising n windings (n > =2). The system 700 also includes a controller 710, the controller 710 controlling the operation of the plurality of power converters 720. The power converter 720 includes one power converter for each winding in the multi-winding PMDC machine 600. For example, the first power converter 722 is associated with a first winding of the PMDC machine 600; a second power converter 724 is associated with a second winding of PMDC machine 600, and so on, an nth power converter 726 is associated with an nth winding of PMDC machine 600.
The power converter 720 facilitates changing the voltage or frequency of the electrical energy provided to the PMDC machine 600. The illustrated power converter includes a physical switch (e.g., a MOSFET) and additional electronic circuitry, such as a gate driver that provides a voltage to a control input port of the switch of the power converter. For example, the control input port of the MOSFET type switch is a gate input terminal. The gate drive output voltage is the result of a command signal sent by the controller 700 to control the current and torque of the PMDC machine.
In the event of a failure of one of the power converters 720 (e.g., the first converter 722), the controller 710 continues to operate the remaining normal power converters (724-726). The respective windings of PMDC machine 600 provide an obtained torque output that is the total torque generated with all windings (and converters) operatingIn other words, the controller 710 bypasses the failed first converter 722 and the corresponding first winding and continues to operate the multi-winding PMDC machine 600 with n-1 windings instead of disabling the PMDC machine 600 entirely.
In addition to using a multi-wound PMDC machine and multiple power converters (H-bridges), the solution herein also facilitates additional levels of redundancy by using multiple microcontrollers that respectively correspond to multiple windings in the multi-PMDC machine 600.
FIG. 8 depicts an example fault tolerant system in accordance with one or more embodiments. The fault tolerant system 700 of fig. 8 has n-level redundancy (n > =2), which is more robust to machine faults, power converter faults, and controller faults, where n is the number of windings in the PMDC machine, the number of power converters, and the number of corresponding controllers. The fault tolerant system 700 of fig. 8 includes a multi-winding PMDC machine 600 having n winding sets and a plurality of power converters 720 corresponding to each winding set. Further, the system 700 includes a controller 710, the controller 710 including a plurality of controllers 812-816, wherein each controller corresponds to one of the plurality of power converters 720. For example, the first controller 812 is associated with the first power converter 722 and further associated with the first winding of the PMDC machine 600. Similarly, the second controller 814 is associated with a second power converter 724, further associated with a second winding of the PMDC machine 600, and so on, until the nth controller 816 is associated with an nth power converter 726, further associated with an nth winding set of the PMDC machine 600.
Each controller 710 operates independently of the other. Thus, in the event of a failure of the first controller 812, the system 700 continues to generate at least a portion of the output torque 550 from the PMDC machine 600 using the remaining (normal) controllers 814-816 of the controller 710. In addition, in the event of a failure of first power converter 722, system 700 continues to generate at least a portion of output torque 550 from PMDC machine 600 using the remaining (normal) power converters 724-726. Furthermore, in the event of a failure of the first winding of PMDC machine 600, system 700 continues to generate at least a portion of output torque 550 from PMDC machine 600 using the remaining (normal) windings of PMDC machine 600.
Fig. 9 illustrates a flowchart of an example method for providing fault tolerance in a PMDC motor control system using a multi-winding PMDC motor in accordance with one or more embodiments. The method comprises the following steps: the current controller 510 of the multi-winding PMDC motor 600 receives the amount of output torque 550 to be generated using the multi-winding PMDC motor driving system as shown at 910. For example, the amount of output torque received may be a desired output torque for an application (e.g., providing assist torque by the steering system 12). Alternatively or additionally, the desired torque may be an amount of torque to be generated for controlling the steering system 12 in the case of a fully automated driving experience, an amount of output torque received from an automated driving assistance unit (not shown) of the vehicle 10.
The method further comprises the steps of: bypassing one winding set associated with the failed microcontroller in the current controller 510 generates a voltage command for each of the other winding sets of the multi-winding motor, as shown at 920. For example, current controller 510 includes a plurality of microcontrollers, each microcontroller associated with a respective winding set of multi-winding PMDC motor 600. Each microcontroller generates a voltage command for a respective winding set based on predetermined parameters (e.g., back emf factor, torque factor, etc.) associated with that winding set. In one or more examples, the parameters are symmetrical among the plurality of winding sets, each microcontroller generating symmetrical voltage commands. Alternatively, the winding sets do not have similar parameter values, and each microcontroller generates a different voltage command. In the event of a microcontroller failure, only the remaining normal microcontrollers generate the corresponding voltage command.
The method further comprises the steps of: the voltage commands are sent to the corresponding winding sets with the power converters running, as shown at 930. For example, each winding set is associated with a respective power converter. In the event of a power converter failure, the corresponding winding set does not receive the corresponding voltage command.
The method further comprises the steps of: bypassing one winding set associated with the failed brush sends a voltage command to the other winding sets of the multi-winding motor, as shown at 940. The voltage command is sent using a terminal pair of the winding that is led out from a brush pair of the winding. For example, if a brush pair fails (e.g., a mechanical failure), the winding set does not receive a voltage command. Thus, only the normal winding set associated with the normal power converter and the normal microcontroller receives the voltage command.
The method further includes generating an output torque based on the voltage command received by the normal winding set, as shown at block 950. If all of the winding sets are normal, the generated output torque matches the received output torque amount, otherwise the output torque is at least a portion of the desired output torque amount. Thus, the system provides fault tolerance because if there is no PMDC motor comprising multiple windings, the motor will not generate any torque at all. Such complete loss of torque may be undesirable in safety critical applications such as steering systems, automatic driving assistance systems.
FIG. 10 depicts an example fault tolerant system architecture in accordance with one or more embodiments. Fault tolerant system 700 of fig. 10 illustrates a multi-layer redundancy architecture that is robust to machine faults, power converter faults, and controller faults. As described herein, PMDC machine 600 with n (n is the number of windings in the PMDC motor, n > =2) level redundancy provides n level redundancy for machine winding faults. Furthermore, architecture 700 provides additional layers of redundancy and robustness by using multiple power converters 720 per winding set. For example, each winding set of PMDC machine 600 is associated with a group of power converters, each group of power converters having k power converters, k+.1. In this configuration, if a first power converter from the k power converter groups fails, one or more of the remaining k-1 power converters take over for the failed power converter operation, thereby providing redundancy and robustness to the failure of the power converter. In one or more examples, k can be 2.
It should be noted that in a typical "normal" operation, multiple power converters in the total number k may be operating, and when a single power converter fails, the remaining k-1 power converters may share the burden in any combination. For example, under normal operation, k-2 converters may be operating, and when one of the operating converters fails, any k-2 converter may begin to operate to keep the system operating as before.
As depicted in the embodiment of the architecture in block 1010, a single controller 710 is associated with all N winding sets of PMDC machine 600. Thus, each of the k power converters in the N groups of power converters is controlled by a single controller 710.
Further, in one or more examples, architecture 700 provides redundancy and robustness of additional layers through the use of multiple controllers 710. For example, each winding set of PMDC machine 600 is associated with a respective set of controllers 812, 814, 816. Each set of controllers may have q controllers, q.gtoreq.1. In this configuration, if a first controller from the group of q controllers fails, one or more of the remaining q-1 controllers take over the failed controller operation, thereby providing redundancy and robustness to the failure of the controller. In one or more examples, q can be 2. As shown in the embodiment of the architecture in block 1020, a set of q controllers 812 (814 and 816) is associated with each respective winding set of the PMDC machine 600.
It should be noted that in a typical "normal" operation, multiple controllers in the total q may be operating, and when a single controller fails, the remaining q-1 controllers may share the burden in any combination. For example, under normal operation, q-2 controllers may be operating, and when one of the operating controllers fails, any q-2 controllers may begin to operate to keep the system operating as before.
The use of multiple (k) power converters in conjunction with each winding set and multiple (q) controllers for each winding set, through multiple (N) winding sets, contributes to the multi-layer configurable redundancy and robustness of fault tolerant system 700.
The solutions described herein facilitate various fault tolerant systems using multi-winding PMDC machines. Furthermore, these solutions also help the fault tolerant system to have n-level redundancy, be more robust to machine and power converter faults (single controller) and be more robust to controller faults (multiple controllers). The PMDC-based electric drive system architecture described herein facilitates multi-level redundancy in motors, power converters, and logic circuits (controllers). Thus, the drive architecture helps to improve fault tolerance and fail safe operation in safety critical systems such as steering systems, automatic driving assistance systems, and the like.
The present technical solution may be a system, a method and/or a computer program product to any degree of possible technical detail integration. The computer program product may include a computer-readable storage medium (or media) having computer-readable program instructions thereon for causing a processor to perform aspects of the present technique.
Aspects of the present technology are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the technology. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.
The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present technology. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
It should also be appreciated that any of the modules, units, components, servers, computers, terminals, or devices illustrated herein that execute instructions may include or otherwise access a computer readable medium, such as a storage medium, computer storage medium, or data storage device (removable and/or non-removable), such as a magnetic disk, optical disk, or magnetic tape. Computer storage media may include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Such computer storage media may be part of, or accessible by, the device. Any of the applications or modules described herein may be implemented using computer-readable/executable instructions that may be stored or otherwise accommodated by such computer-readable media.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the technical solution can be modified to include any number of variations, changes, substitutions, or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the technical solution. In addition, while various embodiments of the subject matter have been described, it is to be understood that aspects of the subject matter may include only some of the described embodiments. Accordingly, the technical solution should not be considered as being limited by the foregoing description.
Claims (10)
1. A system, comprising:
a permanent magnet direct current, PMDC, motor comprising a plurality of winding sets:
a first winding set including a first pair of poles, a first pair of brushes, and a first winding;
a second winding set comprising a second pair of poles, a second pair of brushes, and a second winding, wherein the first winding and the second winding are symmetrically arranged, the first winding set having a first pair of terminals, the second winding set having a second pair of terminals, and wherein the first pair of terminals are drawn from the first pair of brushes, the second pair of terminals are drawn from the second pair of brushes, the first pair of terminals and the second pair of terminals being separately provided; and
a plurality of power converters, wherein each group of power converters corresponds to a respective winding set; and
a controller configured to cause the PMDC motor to generate a predetermined amount of torque by:
applying a first voltage command to the first winding set, the first winding set generating a first current in response to the first voltage command;
applying a second voltage command to the second set of windings, the second set of windings generating a second current in response to the second voltage command; and
the first and second currents cause the motor to generate the predetermined amount of torque;
wherein when one power converter of a group of power converters fails, the remaining power converters of the group of power converters are operable in any combination to maintain the system operational.
2. The system of claim 1, wherein the controller comprises a plurality of controllers, wherein each controller corresponds to one winding set, wherein a first controller is to generate the first voltage command for the first winding set and a second controller is to generate the second voltage command for the second winding set.
3. The system of claim 1, wherein the controller comprises: a plurality of controllers, wherein each group of controllers corresponds to a winding set.
4. The system of claim 1, wherein in response to a brush failure of the first winding set, the controller skips generating the first voltage command, continuing to generate the second voltage command for the second winding set.
5. A permanent magnet direct current, PMDC, motor comprising:
a plurality of winding sets, comprising:
a first winding set including a first pair of poles, a first pair of brushes, and a first winding;
a second winding set including a second pair of poles, a second pair of brushes, and a second winding; and a plurality of power converters, wherein each group of power converters corresponds to a respective winding set; wherein the first winding set generates a first current command in response to a first voltage command from a controller;
the second winding set generates a second current command in response to a second voltage command from the controller; and is also provided with
Wherein the first winding and the second winding are symmetrically arranged, the first winding set having a first pair of terminals and the second winding set having a second pair of terminals, and wherein the first pair of terminals is led from the first pair of brushes and the second pair of terminals is led from the second pair of brushes, the first pair of terminals and the second pair of terminals being provided separately;
wherein when one of the power converters of a group fails, the remaining power converters of the group are operable in any combination to maintain operation of the PMDC motor.
6. A PMDC motor according to claim 5 wherein the controller comprises a plurality of controllers, wherein each controller corresponds to one winding set, a first controller for generating the first voltage command for the first winding set and a second controller for generating the second voltage command for the second winding set.
7. The PMDC motor according to claim 5, wherein the controller includes: a plurality of controllers, wherein each group of controllers corresponds to a winding set.
8. A method for generating an output torque of a multi-winding PMDC motor, the method comprising:
generating, by a current controller, a first voltage command for a first winding set of a plurality of winding sets of the PMDC motor, the first winding set generating a first current in response to the first voltage command; and
generating, by the current controller, a second voltage command for a second winding set of a plurality of winding sets of the PMDC motor, the second winding set generating a second current in response to the second voltage command; and
generating, by the PMDC motor, the output torque based on the first current and the second current;
wherein the first winding set comprises a first winding, the second winding set comprises a second winding, and the first winding and the second winding are symmetrically arranged, the first winding set has a first pair of terminals, the second winding set has a second pair of terminals, and wherein the first pair of terminals are led out from a first pair of brushes, the second pair of terminals are led out from a second pair of brushes, and the first pair of terminals and the second pair of terminals are separately provided; and is also provided with
Wherein the PMDC motor is associated with a plurality of power converters, wherein each group of power converters corresponds to a respective winding set, and when one of the group of power converters fails, the remaining power converters of the group of power converters are operable in any combination to maintain operation of the PMDC motor.
9. The method of claim 8, wherein the current controller comprises a plurality of controllers, wherein each controller corresponds to one winding set, a first controller is used to generate the first voltage command for the first winding set, and a second controller is used to generate the second voltage command for the second winding set.
10. The method of claim 8, wherein in response to a brush failure of the first winding set, the controller skips generating the first voltage command and continues generating the second voltage command for the second winding set.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US2017/063692 WO2019108176A1 (en) | 2017-11-29 | 2017-11-29 | Fault tolerant permanent magnet dc motor drives |
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| CN111448750A CN111448750A (en) | 2020-07-24 |
| CN111448750B true CN111448750B (en) | 2024-03-12 |
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| CN201780097310.1A Active CN111448750B (en) | 2017-11-29 | 2017-11-29 | Fault tolerant permanent magnet DC motor driver |
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| WO (1) | WO2019108176A1 (en) |
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| CN2324696Y (en) * | 1997-11-25 | 1999-06-16 | 湖南省跃进机械厂 | Disk type DC permanent-magnet hub motor for electric booster |
| CN101267956A (en) * | 2005-09-23 | 2008-09-17 | 通用汽车环球科技运作公司 | Multiple inverter system with single controller and related operating method |
| CN104170242A (en) * | 2013-03-15 | 2014-11-26 | 日本精工株式会社 | Motor control device, and electric power steering device and vehicle using same |
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| WO2019108176A1 (en) | 2019-06-06 |
| CN111448750A (en) | 2020-07-24 |
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