Method of determining set torque for motor that enables control of DC current being consumed
Patent Information
- Application Number
- JP2024140076
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-08-24
- Filing Date
- 2024-08-21
- Publication Date
- 2025-03-07
Smart Images
Figure 2025031651000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to the field of electric motors, and in particular to a method for determining a parameter representative of the set torque of an electric motor.
[0002] The invention applies to electric motors, in particular brushless electric motors, independent of the number of phases and windings, driven by a vector control method, the electric motor receiving an AC supply current from an inverter driven by this vector control method, the inverter being supplied with a DC supply current. [Background technology]
[0003] In the following, a direct supply current is called a direct current and an alternating supply current is called an alternating current.
[0004] In the following, the system upstream of the inverter, responsible for supplying or recovering the direct current of the inverter, is called the direct current supply system, i.e. the direct current system. For example, this upstream system can be a battery or a DC-DC converter.
[0005] The inverter converts the direct current into alternating current that is supplied to the motor.
[0006] Vector control, also called field-oriented control, is a known control method for electric motors in which the AC current of the motor is decomposed into two orthogonal components, a component along the q-axis, hereafter called quadrature current and denoted lq, and a component along the d-axis, hereafter called direct current and denoted ld. The quadrature current lq and the direct current ld are space currents in the so-called direct axis of magnetization, denoted d, and the quadrature axis, denoted q. The quadrature current lq and the direct current ld correspond to the spatial projection of the three-phase current system onto a rotating reference frame related to the rotor of the electric motor. Thus, the quadrature current lq and the direct current ld are functions of the phase shift of the three-phase current system with respect to the direct axis d and the amplitude of the three-phase current system. In low-reluctance motors, the direct current ld generally allows a reduction of the sensed magnetic flux to optimize operation at high speeds, while the quadrature current lq controls the torque provided by the motor, hereafter called motor torque. The direct current ld and the quadrature current lq are determined based on an operating point of the motor characterized by at least one parameter, for example, a set torque, a rotational speed of the motor, a temperature of the motor, and a voltage of an AC voltage supplied to the motor.
[0007] The motor is supplied with an alternating current having a direct axis component ld and a quadrature axis component lq and provided by an inverter. Summary of the Invention [Problem to be solved by the invention]
[0008] The invention finds particular application in the field of power steering for vehicles, where car manufacturers are striving to control more precisely the power consumption of the power steering system, in other words the direct current supplied.
[0009] The purpose of a vehicle steering system is to allow the driver to control the vehicle's path by modifying the steering angle of the vehicle's wheels via the steering wheel. The power consumption of an electric power steering system is difficult to predict, as it depends on the forces transmitted by the wheels (parking maneuvers, driving, low grip, etc.) and the driver's desire to turn the steering wheel. However, electric power steering systems have the ability and tendency to consume very large amounts of power.
[0010] There are various solutions that make it possible to control the power consumption of a power steering system: some are based on controlling the supply voltage to the motor at the AC level, others on the motor torque or the quadrature current lq.
[0011] Solutions based on motor torque control or quadrature current lq have the advantage of maintaining control of the set torque, which is not possible by acting on the supply voltage to the motor. However, this control requires complex design and development to guarantee performance and stability over the entire operating range (temperature, speed, etc.), since the consumed DC current depends on several inputs, including the (controlled) motor torque, the supply DC voltage to the inverter, the rotational speed of the motor, and, to a lesser extent, the variations of some parameters related to production and / or temperature and / or ageing. Production is understood as use and / or manufacturing. Indeed, some parameters, such as the electrical resistance of the motor windings, the magnetic flux, vary from motor to motor during production under the same environmental conditions, and these parameters also vary with temperature.
[0012] The present invention aims to remedy all or some of the aforementioned disadvantages by determining a parameter representative of the set torque of the motor, making it possible to ensure compliance with the constraints on the DC current consumed. [Means for solving the problem]
[0013] The object of the invention is a method for determining a parameter representative of a set torque of a motor, said motor being supplied with an alternating current from at least one inverter, said at least one inverter being driven by at least one microcontroller using a vector control method, said at least one inverter being supplied with a direct current from at least one direct current supply system, said method being executed by said at least one microcontroller, said method comprising: a control step in which a control parameter is determined based on at least a DC current threshold, a measured DC current, and a limiting parameter; an adjusting step in which a command variable is determined based on at least the DC current threshold and the measured DC current; a determining step in which upper and lower limits of the parameter representative of the set torque are determined based on at least the command variable; An evaluation step in which the parameter representative of the set torque is determined based on at least the upper and lower limits of the parameter representative of the set torque and a parameter representative of a desired torque.
[0014] The set torque is the torque that the motor must provide. The set torque is processed in the microcontroller to determine the direct and quadrature currents to enable the motor to provide the set torque. During normal operation, the set torque substantially corresponds to the torque that the motor provides, i.e. the motor torque.
[0015] Motor torque is the torque actually exerted by the motor. It depends on the AC current supplied to the motor. Motor users want the motor torque to be close to or equal to the set torque.
[0016] In the following, all the elements making it possible to control an electric motor are called the motor system, which in particular comprises the motor and inverter assembly and the microcontroller.
[0017] The electric motor according to the invention is supplied with an alternating current provided by an inverter, which itself is electrically supplied with a direct current.
[0018] The alternating current supplied to the motor is determined on the basis of parameters representative of the set torque determined by the method according to the invention.
[0019] The method comprises an adjusting step, executed by the microcontroller, during which a command variable is determined based on a DC current threshold and a measured DC current.
[0020] The DC current threshold is the maximum value of DC current consumed that is desired not to be exceeded. In other words, during operation of the motor, the DC current threshold corresponds to a regulation value of the DC current. The DC current threshold is determined by the user.
[0021] The measured DC current corresponds to the value of the DC current actually consumed by the motor during the previous iteration. The method according to the invention adjusts the measured DC current so as to keep it below the DC current threshold. The command variable corresponds to the command virtual DC current and makes it possible to keep the maximum value of the consumed DC current below the DC current threshold.
[0022] The adjustment step makes it possible, on the one hand, to compensate for parameter variations, in particular the motor flux and resistance, whose values vary based on temperature and during manufacture relative to reference values built into the control, and, on the other hand, the dynamics of the lower level regulation loops, which may generate certain delays in controlling the desired torque.
[0023] The limiting parameter includes an active state and an inactive state, indicating that limiting of the parameter representing the set torque is performed during the evaluation step. Thus, the state of the limiting parameter is determined during the evaluation step.
[0024] During the control step, the microcontroller 20 activates or deactivates the adjustment of the measured DC current according to the value assumed by the control parameter. In other words, the microcontroller makes it possible to execute the adjustment step according to several conditions. To that end, the control parameter is in an active or inactive state depending on at least the DC current threshold, the measured DC current and the limit parameter. The control step makes it possible to continuously adjust the parameter representative of the set torque by the limit parameter. The method adjusts the measured DC current when the set torque is exceeded or limited. In other words, the adjustment and decision steps are only executed when the measured DC current is equal to or greater than the DC current threshold and until the limit parameter indicates an inactive state.
[0025] The method comprises a determination step, during which upper and lower limits for a parameter representative of the set torque are determined based on at least the command variable. The determination step thus follows the adjustment step.
[0026] The upper and lower limits define the range of values that the parameter representing the set torque must take, ensuring that the measured DC current, i.e. the DC current consumed by the motor, remains below the DC current threshold.
[0027] This step does not involve the calculation or adjustment of complex variables since the variations in the physical parameters of the motor system are taken into account by the command variables.
[0028] The method finally comprises an evaluation step, in which a parameter representative of the set torque is determined based on the upper and lower limits of the parameter representative of the set torque and on the parameter representative of the desired torque.
[0029] The desired torque is the torque that the user wants the motor to exert, regardless of the DC current consumed. The desired torque is determined by a high level controller. In the case of a power steering system, the desired torque is determined based, among other things, on the steering wheel torque applied to the steering wheel by the driver.
[0030] The parameter representative of the set torque should therefore be as close as possible to the parameter representative of the desired torque whilst remaining within a range of values determined by the upper and lower limits, so that the evaluation step can be effected by limiting the parameter representative of the desired torque by the upper and lower limits.
[0031] According to one embodiment, the evaluation step determines the limiting parameter based on at least a parameter representative of the set torque and a parameter representative of the desired torque.
[0032] The limiting parameter indicates whether limiting of the parameter representing the desired torque was performed during the evaluation step.
[0033] The adjusting and determining steps are performed only when the measured DC current is greater than or equal to the DC current threshold or when the adjusting loop limits the set torque, as indicated by the state of the limit parameter.
[0034] According to one embodiment, the limiting parameter is in an active state when the parameter representative of the set torque differs from the parameter representative of the desired torque.
[0035] According to one embodiment, the limiting parameter is inactive when the parameter representing the set torque is equal to the parameter representing the desired torque.
[0036] The principle of the method according to the invention is to take into account deviations of the physical parameters of the motor by means of command variables when a limitation of the consumed DC current is required, and then, on this basis, to determine a range of values for the parameters representative of the set torque of the motor, which makes it possible to ensure that the consumed DC current is below the DC current threshold value.
[0037] The invention may include one or more of the following features, either alone or in combination.
[0038] According to one embodiment, the electric motor is a power steering motor of a vehicle.
[0039] According to one embodiment, the control parameter has a value of 1 in the active state and a value of 0 in the inactive state.
[0040] The control step enables proper implementation of the adjustment of the measured DC current by activating the adjustment step only when necessary.
[0041] According to one embodiment, the adjusting step is performed when the control parameter is in an active state.
[0042] As long as the measured DC current is below the DC threshold value, divergence of the command variable is thus avoided.
[0043] When the control parameters are in an active state, the parameter representing the set torque should therefore be as close as possible to the parameter representing the desired torque while adhering to the range of values determined by the upper and lower limits.
[0044] When the control parameters are inactive, the parameter representing the set torque is equal to the parameter representing the desired torque, the upper and lower limits are not taken into account, and no adjustment of the consumed direct current is made.
[0045] The adjusting and determining steps are performed only when the control parameter is active, i.e. when the method adjusts or limits the measured DC current to the DC current threshold, i.e. as long as the set torque is limited.
[0046] According to one embodiment, the evaluating step determines a parameter representative of the set-point torque based on the control parameter.
[0047] According to one embodiment, the parameter representative of the set torque and the parameter representative of the desired torque correspond to a torque or a quadrature current.
[0048] Thus, the method determines the set torque or set quadrature current in the same way.
[0049] According to one embodiment, the method further comprises a driving step, in which the at least one inverter is driven by the microcontroller based on the parameter representative of the set torque.
[0050] According to one embodiment, the adjustment step determines the command variable by the sum of the DC current threshold and a corrective action value determined by an integral and / or differential and / or proportional controller receiving the DC current threshold and the measured DC current as inputs.
[0051] The command variable is obtained by the sum of a feedforward, which corresponds directly to the DC current threshold, and a corrective operating value resulting from a closed-loop control of the proportional, integral, differential or combination thereof type, which makes it possible to compensate for parameter variations, in particular the motor flux and resistance, whose values vary according to temperature and during manufacture with respect to reference values built into the control, and on the other hand the dynamics of the lower level regulation loops, which may generate a certain delay in controlling the desired torque.
[0052] The upper and lower limits of the parameter representing the set torque are obtained by solving a mathematical equation which is a function of at least the command variable, the rotational speed of the motor, the DC voltage supplied to the inverter, and the direct axis current of the AC current supplied to the motor measured or determined during a previous iteration.
[0053] The equations solved in the determination step are obtained from the general equations for motors in the direct and quadrature axes.
[0054] According to one embodiment, the general formula is:
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[0055] According to one embodiment, the formula is a function of physical parameters of the motor.
[0056] The physical parameters of the motor are, for example, the total equivalent resistance on the AC side, the equivalent magnetic flux, the equivalent resistance, the direct and quadrature inductances, and the number of pole pairs. These parameters are the result of the motor sizing. For simplicity, these parameters are assumed to be constant when solving the equations, and fixed reference values are used.
[0057] The transform coefficients in the selected uvw-dq0 transform are fixed gains corresponding to the selected rule.
[0058] According to one embodiment, the method comprises a calculation step in which a conversion gain is determined based on a conversion coefficient in a uvw-dq0 transformation, the number of pole pairs of the motor, the equivalent magnetic flux of the motor in the uvw-dq0 transformation, the direct axis current of the AC current supplied to the motor measured or determined during the previous iteration, and the direct axis inductance and quadrature axis inductance of the motor.
[0059] According to one embodiment, the conversion gain is calculated according to the formula:
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[0060] According to one embodiment, the upper and lower limits of the parameter representing the set torque are determined by the following formula:
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[0061]
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[0062] In one embodiment, the control parameter changes to an active state when the measured DC current is greater than or equal to the DC current threshold, and changes to an inactive state when the measured DC current is less than the DC current threshold and the parameter representing the set torque is equal to the parameter representing the desired torque.
[0063] Thus, the limitation imposed by the method is effective when the measured DC current is equal to or greater than the DC current threshold, and ceases when the measured DC current falls below the DC current threshold and the method no longer applies the limitation.
[0064] In one embodiment, the control parameters begin in an inactive state.
[0065] By default, no limit is applied to the parameter representing the set torque, only when it is determined that the DC current threshold is exceeded.
[0066] The invention also relates to a power steering system comprising at least one motor controlled by the method according to the invention. [Brief description of the drawings]
[0067] The invention will be better understood from the following description of embodiments according to the invention, given as non-limiting examples and explained with reference to the attached schematic drawings, in which: [Figure 1] FIG. 1 is a schematic diagram of a power steering system incorporating the method according to the invention. [Diagram 2] FIG. 2 is a block diagram of the motor power supply. [Diagram 3] FIG. 3 is a diagram of a method according to the invention. [Figure 4] FIG. 4 is a diagram showing the upper and lower limits of the parameter representing the set torque as a function of the rotation speed of the motor. [Diagram 5] FIG. 5 shows a simulation over time of the motor rotation speed, the parameters representing the desired and set torque, the measured DC current, the DC current threshold, the command variables, the limit parameters and the control parameters. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0068] As illustrated in Figure 1, the steering system 1 of a vehicle 2 is intended to enable a driver to control the course of the vehicle 2 by modifying the steering angle of the vehicle's wheels 10, 11 by means of a steering wheel 3. The steering angle of the wheels is particularly related to the angle θ3 of the steering wheel 3. The driver modifies the angle θ3 of the steering wheel 3 by applying a force T3 to the steering wheel 3, hereinafter referred to as the "steering wheel torque".
[0069] In general, the steering system 1 comprises several elements including a steering wheel 3, a rack 6 and two wheels 10, 11 connected to tie rods 8, 9 respectively. The rack 6 is the part that allows the wheels 10, 11 to be steered, i.e. to modify the angle of orientation of the wheels 10, 11 by means of the tie rods 8, 9. The rack 6 converts a change in the angle of the steering wheel 3 into a change in the angle of orientation of the wheels 10, 11 of the vehicle.
[0070] The electric power steering 1 includes a power supply system for a motor 12, as shown in FIG. IN is determined in a manner known to those skilled in the art based on the force T3 applied to the steering wheel 3, in particular by the high-level controller 200. IN The parameter that represents the DC current consumed I DC is the torque that a user desires the motor 12 to exert, independent of
[0071] Next, the method 100 of the present invention calculates the desired torque X IN A set torque X provided by the electric motor 12 based on a parameter representing OUT Find the parameters that represent:
[0072] Set torque X OUT are converted by the modulation unit 300 into a set of variables M, making it possible to drive the inverter 40 by a vector control method.
[0073] The inverter 40 is supplied with a direct current I DC is supplied, and the inverter 40 outputs a DC current I DC is the AC current I supplied to the motor 12. AC Convert to AC supply current I AC In the following, the direct axis current I d and a quadrature component hereafter referred to as quadrature axis current.
[0074] DC current IDC is the supply voltage V DC and is supplied by a direct current supply system 30, i.e. a direct current system, which may for example be a battery or a DC-DC converter.
[0075] Motor 12 operates at a set torque of X OUT The motor torque T12 is applied to the rack 6 based on a parameter representing the AC current I supplied to the motor 12. AC The user of the motor 12 determines whether the motor torque T12 is equal to the desired torque X IN The torque saturation torque saturation torque saturation torque saturation torque saturation torque
[0076] All the elements making it possible to control the electric motor 12 are referred to below as the motor system. The motor system includes in particular the motor and inverter assembly and the microcontroller 20.
[0077] Electric motor 12 is preferably a bidirectional electric motor and is preferably a rotary electric motor of the brushless type.
[0078] The invention applies, for example, to the electric motor 12 of a mechanical power steering system, i.e. in which there is a mechanical link generally operated by a steering column 4 which meshes with a rack 6 by means of a steering pinion 5, the rack 6 being guided for translation in a casing 7 fixed to the vehicle 2, or, not shown, to an electric power steering system which does not have a mechanical link and is called "steer-by-wire", in which the steering wheel is mechanically decoupled from the rack.
[0079] In the case of mechanical power steering, the electric motor 12, through a gear reduction type reducer, can either engage with the steering column 4 itself to form a so-called "single pinion" mechanism, or, as shown in FIG. 1, can engage directly with the steering rack 6, for example by means of a second pinion 13 different from the steering pinion 5 that allows the steering column 4 to mesh with the rack 6 to form a so-called "double pinion" mechanism.
[0080] The present invention more particularly relates to a method for controlling a synchronous electric motor 12, which may be an electric motor 12 in a steering system as shown in FIG. 1 or in other applications.
[0081] A method 100 according to the present invention is depicted in FIG.
[0082] The method 100 according to the present invention is carried out by determining a set torque X, which may be a torque or a quadrature current. OUT Similarly, we obtain the parameters that represent the desired torque X IN The parameter representing corresponds to the torque or the quadrature axis current.
[0083] The method 100 comprises a control step E1, which has as input a DC current threshold I DCMax , measured DC current I DCMes and calculates the control parameter CTL.
[0084] The control step E1 also receives as input a limit parameter LIM.
[0085] DC current threshold I DCMax is the DC current consumed, I, which should not be exceeded DC In other words, during operation of the motor 12, the DC current threshold I DCMax is the DC current I DC Corresponds to the regulation value of DC current threshold I DCMax is determined by the user.
[0086] Measured DC current I DCMesis the DC current actually consumed by the motor 12 during the previous iteration, I DC The method 100 according to the invention corresponds to a value of the DC current threshold I DCMax The measured DC current I is kept below DCMes Adjust.
[0087] During the control step E1, the microcontroller 20 determines the actual consumed direct current I DC In other words, the microcontroller 20 enables the execution of the method 100 according to the invention. To that end, the control parameter CTL is set to the DC current threshold I DCMax , measured DC current I DCMes , and the limit parameter LIM, it is in an active state ON or in an inactive state OFF.
[0088] According to one embodiment, the control parameter CTL has a value of 1 for an active state ON and 0 for an inactive state OFF.
[0089] According to one embodiment, the control parameter CTL starts in an inactive state OFF, i.e.
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[0090] According to one embodiment, the control parameter CTL is determined by the measured DC current I DCMes is the DC current threshold I DCMax When the measured DC current I DCMes is the DC current threshold I DCMax The inactive state is OFF when the limit parameter LIM is less than the threshold value and the limit parameter LIM is in the inactive state OFF.
[0091] In other words,
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[0092] The limitations of Method 100 are that the measured DC current I DCMes is the DC current threshold I DCMax Valid when the measured DC current I DCMes is the DC current threshold I DCMax If the torque limit is less than the set torque X, the method 100 will stop and will not limit the torque further. OUT No limit is imposed on the parameter representing the DC current threshold I DCMax is exceeded.
[0093] The control step adjusts the measured DC current I DCMes This allows for appropriate adjustment of the
[0094] The method 100 comprises an adjustment step E2. In this step, the command variable I DCCom is the DC current threshold I DCMax and the measured DC current I DCMes It is determined based on the following.
[0095] Command variable I DCCom corresponds to the virtual DC current of the command, and the maximum DC current consumed is set to the DC current threshold I DCMax It allows you to keep:
[0096] The adjustment step makes it possible, on the one hand, to compensate for parameter variations, in particular the motor flux and resistance, whose values vary based on temperature and during manufacture relative to reference values built into the control, and, on the other hand, the dynamics of the lower level regulation loops, which may generate certain delays in controlling the desired torque.
[0097] According to one embodiment, the adjustment step E2 is executed when the control parameter CTL is in the active state ON.
[0098] Measured DC current I DCMes is the DC current threshold IDCMax As long as it is less than the command variable I DCCom Divergence of is thus avoided.
[0099] The regulation step E2 takes as input a DC current threshold I DCMax and the measured DC current I DCMes The corrective action value ΔI determined by the integral and / or differential and / or proportional controller E21 receives DC and DC current threshold I DCMax By adding with, the command variable I DCCom Request.
[0100] The method 100 comprises a decision step E3. During this step, the set torque X OUT The upper limit of the parameter X LimMax and lower limit X LimMin However, at least the command variable I DCCom Thus, the determination step E3 follows the adjustment step E2, and these steps are performed when the control parameter CTL is in the active state ON, i.e. when the method 100 determines that the measured DC current I DCMes DC current threshold I DCMax In other words, the adjustment step E2 and the determination step E3 are performed only when the measured DC current I DCMes is the DC current threshold I DCMax Only when it must be less than the set torque X OUT is restricted, it will be executed.
[0101] Upper limit X LimMax and lower limit X LimMin is the set torque X OUT It specifies the range of values that the parameter representing the measured DC current I must take. DCMes That is, the DC current consumed by the motor 12 exceeds the DC current threshold I DCMax The variation of the physical parameters of the motor 12 is DCCom This step E3 does not involve the calculation or adjustment of complex variables, since all variables are taken into account by
[0102] According to one embodiment, the set torque X OUT The upper limit of the parameter X LimMax and lower limit X LimMin is at least the command variable I DCCom , the rotation speed Ω of the motor 12, and the DC voltage V supplied to the inverter 40. DC , and the direct current I supplied to the motor 12 and measured or determined during the previous iteration. AC The direct axis current I d It is obtained by solving the equation, which is a function of .
[0103] According to one embodiment, the formula is a function of physical parameters of the motor.
[0104] The physical parameters of the motor are, for example, the total equivalent resistance on the AC side, the equivalent magnetic flux, the equivalent resistance, the direct or quadrature inductance, and the number of pole pairs. These parameters are the result of the motor sizing. For simplicity, these parameters are assumed to be constant when solving the equations, and fixed reference values are used.
[0105] The transform coefficients in the selected uvw-dq0 transform are fixed gains corresponding to the selected rule.
[0106] Conversion gain G Iq2Trq is calculated during the calculation step E5 by the conversion coefficient k in the uvw-dq0 conversion, the number of pole pairs p of the motor 12, the equivalent magnetic flux Ψ of the motor in the uvw-dq0 conversion, the AC current I supplied to the motor 12 and measured or determined during the previous iteration AC The direct axis current I d , and the direct-axis inductance L of the motor d and the quadrature inductance L q It is required according to.
[0107] According to one embodiment, the conversion gain is calculated according to the formula:
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[0108] The equations solved in decision step E3 are obtained from the general equations for the motor 12 in the direct and quadrature axes.
[0109] According to one embodiment, the general formula is:
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[0110] According to one embodiment, the set torque X OUT The upper limit of the parameter X LimMax and lower limit X LimMin is expressed by the following formula:
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[0111]
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[0112] The method finally comprises an evaluation step E4, in which the set torque X OUT The parameter representing the set torque X OUT The upper limit of the parameter X LimMax and lower limit X LimMin , the control parameter CTL, and the desired torque X IN It is calculated based on the parameters representing:
[0113] When the control parameter CTL is in the active state ON, the set torque X OUT The parameter representing the upper limit X LimMax and lower limit X LimMin The desired torque X is obtained while observing the range of values determined by IN In other words,
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[0114] When the control parameter CTL is inactive, the set torque X OUT The parameter representing the desired torque X IN The parameter represents the upper limit X LimMax and lower limit X LimMin is not taken into account. No regulation of the DC current consumed is performed. In other words,
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[0115] According to one embodiment, the evaluation step E4 determines the limit parameter LIM as a function of at least the set torque X OUT and the desired torque X IN It is calculated based on the parameters representing:
[0116] The limiting parameter LIM is the desired torque x IN whether a limitation of the parameter representing has been performed during evaluation step E4.
[0117] According to one embodiment, the set torque X OUT The parameter representing the desired torque X IN The limit parameter LIM is in the active state ON when it is different from the parameter representing
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[0118] According to one embodiment, the set torque X OUT The parameter representing the desired torque X IN The limit parameter LIM is in the inactive state OFF when it is equal to a parameter representing
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[0119] Finally, the method includes the step of: OUT The method further comprises a driving step, which is driven by the microcontroller 20 based on a parameter representing:
[0120] The principle of the method 100 according to the invention is that the consumed direct current I DC When a limit is required, the command variable I DCCom Then, based on this, the set torque X of the motor 12 is calculated. OUT The purpose of this study is to obtain the range of values of the parameter that represents the DC current I DC ensure that the DC current threshold I DCMax It is possible to:
[0121] FIG. 4 shows the solution I of the equation solved for DC current thresholds of 50 A and 5 A based on the rotational speed Ω of the motor 12 during the determination step. qLimMax ,I qLimMin Shows.
[0122] FIG. 5 shows the rotational speed Ω of the motor 12 and the desired torque T IN and set torque T OUT A parameter that represents the measured DC current I DCMes , DC current threshold I DCMax , command variable I DCCom , the limiting parameter LIM, as well as the control parameter CTL, are shown in time.
[0123] The limit parameter LIM and the control parameter CTL are initially in the inactive state OFF, i.e. at value 0. DCMax is set to 50A.
[0124] The rotation speed Ω of the motor 12 increases and the desired torque T IN When increases, the measured DC current I DCMes increases and the DC current threshold I DCMax This exceedance is followed by the activation of the control parameter CTL, i.e., a change to the value 1, and then the command variable I DCCom Finally, the calculation of the reduced set torque T OUT , which leads to the limit parameter LIM changing to the active state ON, i.e. to the value 1. As a result, the measured DC current I DCMes is the DC current threshold I DCMax and decreases back to the DC current threshold I DCMax is the regulation command value.
[0125] As the decrease in the rotational speed Ω of the motor 12 necessarily widens the gap between the upper limit TLimMax and the lower limit TLimMin of the parameter representing the set torque, in this example coupled with a decrease in the desired torque TIN, the limiting parameter LIM returns to the inactive state OFF. When the measured DC current IDCMes naturally returns below the DC current threshold IDCMax, the control parameter CTL also changes to the inactive state OFF. The desired torque TIN again becomes equal to the set torque TOUT.
[0126] Of course, the invention is not limited to the embodiments described and represented in the attached drawings: modifications are still possible, particularly in terms of the configuration of the various elements and by substitution by technical equivalents, without departing from the scope of protection of the invention.
Claims
1. The set torque (X ＯＵＴ A method (100) for determining a parameter representative of a motor (12), comprising: ＡＣ ) from at least one DC current supply system (30), the at least one inverter (40) being driven by at least one microcontroller (20) using a vector control method, the at least one inverter (40) being supplied with a DC current (I ＤＣ ), the method (100) being executed by the at least one microcontroller (20), the method (100) comprising: The control parameter (CTL) is at least the DC current threshold (I ＤＣＭａｘ ), measured direct current (I ＤＣＭｅｓ ), and a control step (E1) determined based on a limit parameter (LIM), Command variable (I ＤＣＣｏｍ ) is at least the DC current threshold value (I ＤＣＭａｘ ) and the measured DC current (I ＤＣＭｅｓ ) an adjustment step (E2) determined on the basis of The set torque (X ＯＵＴ The upper limit of the parameter (X ＬｉｍＭａｘ ) and lower limit (X ＬｉｍＭｉｎ ) at least the command variable (I ＤＣＣｏｍ ) a decision step (E3) determined on the basis of The set torque (X ＯＵＴ The parameter representing at least the set torque (X ＯＵＴ The upper limit (X ＬｉｍＭａｘ ) and the lower limit (X ＬｉｍＭｉｎ ), and the desired torque (X ＩＮ an evaluation step (E4) based on parameters representative of A method comprising:
2. The set torque (X ＯＵＴ ), and the desired torque (X ＩＮ The parameter representing the torque (T ＯＵＴ , T ＩＮ ) or the quadrature axis current, The method (100) of claim 1.
3. The at least one inverter controls the set torque (X ＯＵＴ ) by the microcontroller (20) based on the parameter representing the The method (100) of claim 1 or 2.
4. The adjusting step (E2) adjusts the DC current threshold (I ＤＣＭａｘ ) and the DC current threshold (I ＤＣＭａｘ ) and the measured DC current (I ＤＣＭｅｓ ) is received by an integral and / or differential and / or proportional controller (E21) ＤＣ ) and the command variable (I ＤＣＣｏｍ ) A method (100) according to any one of claims 1 to 3.
5. The set torque (X ＯＵＴ The upper limit (X ＬｉｍＭａｘ ) and the lower limit (X ＬｉｍＭｉｎ ) is at least the command variable (I ＤＣＣｏｍ ), the rotation speed of the motor (Ω), the DC voltage (V ＤＣ ), and the direct axis current (l) of the AC current supplied to the motor measured or determined during the previous iteration. ｄ ), which is obtained by solving the equation A method (100) according to any one of claims 1 to 4.
6. Conversion gain (G Ｉｑ２Ｔｒｑ ) is a conversion coefficient in the uvw-dq0 conversion, the number of pole pairs (p) of the motor, the equivalent magnetic flux (Ψ) of the motor in the uvw-dq0 conversion, the direct axis current (l) of the AC current supplied to the motor measured or determined during the previous iteration, ｄ ), and the direct-axis inductance (L ｄ ) or quadrature axis inductance (L ｑ ) based on the calculation step (E5), The method (100) of claim 5.
7. The control parameter (CTL) is The measured DC current (I ＤＣＭｅｓ ) is the DC current threshold value (I ＤＣＭａｘ ) or more, it changes to the active state (IN), The measured DC current (I ＤＣＭｅｓ ) is the DC current threshold value (I ＤＣＭａｘ ) and the set torque (X ＯＵＴ The parameter representing the desired torque (X ＩＮ ) the state changes to an inactive state (OFF); The method (100) according to any one of claims 1 to 6.
8. The control parameter (CTL) is initiated in the inactive state (OFF). The method (100) of claim 7.
9. The set torque (X ＯＵＴ at least one motor (12) controlled by said parameters representing Power steering system (1).