Motor control device

Abstract

A motor control device according to the present invention includes: a first torque limit value calculation unit that calculates a first torque limit value based on a first limit element based on a shaft torque output by a motor and a second limit element based on a torque command for the motor in order to operate the motor within a predetermined torque range; calculating a first torque limit value based on the torque command; a second torque limit value calculation unit that calculates a second torque limit value based on the shaft torque on the basis of a subtraction value obtained by subtracting the amount of drag torque corresponding to the physical loss of the motor from the first torque limit value; and a third torque command value calculation unit that calculates a final torque limit value after compensation of the drag torque on the basis of the second torque limit value and a torque command value input from the outside, the first torque limit value calculation unit compares a value obtained by adding an amount of the drag torque to the first limit element with the second limit element, and calculates a final torque limit value after compensation of the drag torque on the basis of the final torque limit value. And a final torque command value calculation unit that compares the second torque limit value with the torque command value, selects the minimum value as the minimum limit value, and calculates the first torque limit value on the basis of the selected minimum limit value, and that compares the second torque limit value with the torque command value, selects the smaller value, and calculates the final torque command value on the basis of the selected minimum limit value. And the final torque command value is calculated by adding the amount of the drag torque to the selected value.

Description

Technical Field

[0001] This invention relates to an electric motor control device. Background Technology

[0002] As part of the electric motor drive system, the power converter control device needs to control the electric motor based on the upper and lower torque limits determined by various parameters such as the motor speed and the induced voltage of the motor. It also needs to perform control based on various torque limiting conditions, such as winding temperature protection, magnet temperature protection, and operating restrictions during fault detection.

[0003] The electric motor generates drag torque in the direction opposite to the direction of rotation and outputs a shaft torque whose absolute value is smaller than the torque estimated based on the voltage and current applied to the motor. Therefore, in order to control the motor so that the supplied torque command and the shaft torque are consistent, the power converter control device performs control to compensate for the pre-measured or estimated drag torque in order to output a shaft torque with high accuracy.

[0004] As an example of such drag torque compensation, Patent Document 1 discloses a motor control device that does not uniformly reflect drag torque compensation, but rather implements adjustments based on the torque determination mechanism of the system and performs drag torque compensation on this basis, thereby reducing vibration.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-211861 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] Previously, a final torque limit was applied after drag torque compensation. Therefore, the amount of drag torque compensation was constrained by the final torque limit, resulting in the inability to achieve maximum output. Furthermore, depending on the order in which drag torque compensation was applied and the definitions of various protection functions, the torque limit set by the protection functions might be exceeded. In this case, the hardware could not be fully protected.

[0010] Technical solutions to solve technical problems

[0011] The motor control device includes: a first torque limit value calculation unit, which calculates a first torque limit value based on a torque command in order to operate the motor within a specified torque range, based on a first limit element based on the shaft torque output by the motor and a second limit element based on a torque command for the motor; a second torque limit value calculation unit, which calculates a second torque limit value based on the shaft torque based on a subtraction value obtained by subtracting a drag torque corresponding to the physical losses of the motor from the first torque limit value; and a third torque command value calculation unit, which calculates a second torque limit value based on the first torque limit value. The first torque limit calculation unit calculates the final torque limit value after compensating for the drag torque by comparing the value obtained by adding the drag torque to the first limit element and the second limit element, selecting the smaller value as the minimum limit value, and calculating the first torque limit value based on the selected minimum limit value. The final torque command value calculation unit compares the second torque limit value and the torque command value, selects the smaller value, and adds the drag torque to the selected value to calculate the final torque command value.

[0012] Invention Effects

[0013] According to the present invention, even when implementing output limits with different references, appropriate output limits and maximum output torque can be achieved. Attached Figure Description

[0014] Figure 1 This is a structural diagram of the electric motor drive system according to Embodiment 1 of the present invention.

[0015] Figure 2 This is a structural example of the existing final torque command determination logic.

[0016] Figure 3 This is a structural example of the existing final torque command determination logic.

[0017] Figure 4 It shows about Figure 2 , Figure 3 An example of the transfer of the motor's operating point.

[0018] Figure 5 This is a structural example of the final torque command determination logic involved in Embodiment 1 of the present invention.

[0019] Figure 6 This is an example illustrating the transfer of the motor operating point according to the present invention.

[0020] Figure 7 This is a logic diagram of the process related to torque command determination involved in Embodiment 1 of the present invention.

[0021] Figure 8 This is a structural diagram of Embodiment 2 of the present invention after the addition of independent restriction logic. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following description and drawings are examples for illustrating the present invention, and appropriate omissions and simplifications have been made to clarify the description. The present invention may also be implemented in various other forms. Unless otherwise specified, the structural elements may be singular or plural.

[0023] To facilitate understanding of the present invention, the positions, dimensions, shapes, and extents of the constituent elements shown in the accompanying drawings may not represent their actual positions, dimensions, shapes, or extents. Therefore, the present invention is not necessarily limited to the positions, dimensions, shapes, and extents disclosed in the accompanying drawings.

[0024] (Implementation Method 1 and Overall Structure)

[0025] ( Figure 1 )

[0026] The electric motor drive system 1 includes a power conversion circuit 7, a power conversion control device 100, and an electric motor 3. The battery 2 serves as the DC voltage source for the power conversion circuit 7. An X capacitor 6, used for noise reduction, is inserted between the battery 2 and the power conversion circuit 7.

[0027] In the power conversion circuit 7, the DC voltage of battery 2 is converted into a three-phase AC voltage with variable voltage and variable frequency by the power conversion circuit 7 controlled by the power conversion control device 100. The three-phase AC voltage converted by the power conversion circuit 7 is applied to the motor 3, thereby driving the motor 3 to rotate. The power conversion control device 100 includes a current detection device Ict, which measures the three-phase AC current generated by the three-phase AC voltage applied to the motor 3 and is used for the control of the motor 3.

[0028] The motor 3 is equipped with a phase detection device 4 to control the matching of the phase of the three-phase AC voltage with the phase of the induced voltage of the motor 3. The phase detection device 4 can be, for example, a rotary transformer consisting of an iron core and windings, or it can be constructed using a GMR sensor or a Hall element. In addition, the motor 3 is equipped with a motor temperature detection device 5 to detect the temperature of the motor 3, so as to input the temperature information to the power conversion control device 100.

[0029] As control logic, the power conversion control device 100 includes a communication function unit 110, a component temperature detection unit 120, a current control unit 130, a torque command determination unit 140, a component protection function unit 150, a current detection unit 160, a phase detection unit 170, a motor temperature detection unit 180, and a reverse driving determination unit 190.

[0030] The power conversion control device 100 may be configured as a microcomputer, for example, and these functional blocks may be implemented by executing a predetermined program in the microcomputer. Alternatively, some or all of these functional blocks may be implemented using hardware circuits such as logic ICs or FPGAs. Furthermore, the power conversion control device 100 may have a PWM modulation mode determination section or a modulation execution section to determine the switching mode of the semiconductor devices in the power conversion circuit 7.

[0031] The power conversion control device 100 obtains torque command T from a higher-level controller (not shown), such as a vehicle control device. The torque limit value TLim is determined, and the motor 3 is controlled via the power conversion circuit 7 so that the shaft torque output from the motor 3 matches the acquired torque command T. Consistent.

[0032] The power conversion circuit 7 controlling the motor 3 has semiconductor devices to switch the conduction and cutoff of each of the U, V, and W phases. In addition, the three-phase AC currents Iu, Iv, and Iw output from the power conversion circuit 7 to the motor 3 are observed by the current detection device Ict, and their values ​​are sent to the power conversion control device 100, thereby enabling feedback control of the motor 3.

[0033] In this feedback control, the phase detection device 4 is usually used to detect the phase of the rotor (not shown) of the motor 3, and the phase is grasped in the power conversion control device 100. The three-phase current is then converted on the dq axis and divided into d-axis current and q-axis current for control.

[0034] The power conversion control device 100 performs torque limiting based on the torque limit value TLim obtained from the upper controller. Alternatively, the torque limiting method for the motor 3 can be implemented by: obtaining vehicle or structural component fault information from the upper controller based on information output from the communication function unit 110, and then limiting the torque based on information output from the avoidance driving determination unit 190 used for determining vehicle avoidance driving; or calculating the torque limit value internally in the power conversion control device 100 to protect the X capacitor 6, which is installed to reduce noise or smooth the motor drive system 1, from damage.

[0035] For example, if the temperature of the motor exceeds the temperature at which a part of the motor's structural components, namely the windings, can maintain insulation, it may cause a short circuit in the motor, leading to smoke, fire, or it may exceed the heat resistance temperature of the semiconductor devices used in the power conversion circuit 7. In order to reduce the large current as one of the causes, torque limiting of the motor 3 is required.

[0036] Furthermore, if the speed of motor 3 is too high and exceeds the maximum speed that motor 3 can guarantee, the bearings of motor 3 will be damaged, or the rotor will be damaged due to centrifugal force. Therefore, torque limiting of motor 3 is required.

[0037] (Existing example)

[0038] ( Figures 2-4 )

[0039] The structure of the existing final torque command generation logic and drag torque compensation unit will be described. The power conversion control device 100 has a torque command determination unit 140 that outputs a torque limit command to the current control unit 130, and the current control unit 130 outputs a gate drive signal 490 to the power conversion circuit 7 based on the acquired torque limit command.

[0040] The minimum value selection unit 201 acquires a first torque limit value 210a related to overheat protection for the purpose of temperature protection of the motor 3, a second torque limit value 210b related to overheat protection of the semiconductor element, and a torque command value 220. The minimum value selection unit 201 compares the acquired values, selects the minimum value, adds a drag torque 230 to the selected minimum value, and outputs it as the final torque command to the current control unit 130. Figure 4 (a) ~ Figure 4 (c) The action points 510a to 510c are used to explain. Figure 2 Action points under certain circumstances.

[0041] Figure 4 (a) ~ Figure 4 In the curve graph (c), the vertical axis represents the output torque and the horizontal axis represents the rotational speed. Figure 2 In the existing structure, drag torque compensation is applied to the torque command of the action point 510a, which represents the original output intention, so as... Figure 4 As shown in (b), the operation occurs at point 510b on the torque limiter 500, within the speed-torque operating range defined by the original shaft torque reference. When the motor 3 is controlled based on the torque command at this point 510b, the actual shaft torque output from the motor 3 is reduced by an amount equivalent to the drag torque; therefore, as... Figure 4(c) shows that the action will occur at action point 501c. Therefore, if the control error is excluded, action point 510a and action point 510c are basically the same, so the compensation purpose is achieved on the surface.

[0042] However, in Figure 2 If the first torque limit value 210a is determined based on the torque command value, and the amount of drag torque is added to compensate, the motor 3 will be controlled with a torque command that exceeds the limit value, which may fail to protect hardware such as components.

[0043] Then, in different Figure 2 of Figure 3 In the existing structure of the final torque command generation logic and drag torque compensation unit shown, before the minimum value selection unit 201 selects the minimum value from the acquired first torque limit value 210a, second torque limit value 210b, and torque command value 220, a drag torque 230 is added to the torque command value 220. This allows for motor control, reliably ensuring that the final torque command value after drag torque compensation does not exceed the limit value.

[0044] Regarding this situation, through Figure 4 (a) ~ Figure 4 (c) is explained by action points 520a to 520c. Figure 4 (a) shows the action point 520a, which is the original intention of the output action point 520a, to perform drag torque compensation on the torque command, but because Figure 2 The first torque limit value 210a or the second torque limit value 210b is a limit value determined based on the shaft torque; therefore, it is impossible to add a further amount of drag torque on top of it. Therefore, as... Figure 4 As shown in (b), the torque command after drag torque compensation becomes action point 520b, which is no different from action point 520a, and is in a state where the required amount of drag torque has not been fully added.

[0045] Then, when motor 3 is controlled by torque commands based on this, the actual shaft torque output from motor 3 decreases by an amount equivalent to the drag torque, thus becoming Figure 4 (c) shows the action point 520c. The result is that... Figure 3 The drag torque compensation of the shaft torque T output by the motor 3 shown is insufficient, resulting in the inability to achieve the predetermined maximum torque. Furthermore, while batch processing of drag torque can be implemented by unifying all mapping references with shaft torque or torque commands, this is difficult to achieve easily due to limitations in the matching methods, design, and timing of each mapping.

[0046] ( Figure 5 )

[0047] In this invention, in the power conversion control device 100, Figure 1 The communication function unit 110 receives torque command T from a host controller or other source not shown in the figure. After checking for outliers and missing data, the torque limit value TLim is transmitted to the torque command determination unit 140. The following details the relationship between the torque command determination unit 140 and the torque command T. Processing related to the torque limit value TLim.

[0048] The torque command constraint element 140, the shaft torque constraint element 420, and the drag torque 230 of the motor 3 are input to the torque command determination unit 140. In the torque command determination unit 140, the adder 421 adds the drag torque 230 to the shaft torque reference constraint element 420, thereby converting it into a torque command reference constraint element 430. Thus, the torque command reference constraint element 410 and the shaft torque reference constraint element 420 can be unified into a torque command reference constraint element.

[0049] Next, the first minimum value selection unit 201 acquires the limiting element 410 and the limiting element 430, which are based on the torque command reference. The first minimum value selection unit 201 compares the limiting element 410 and the limiting element 430, selects the one with the smallest value, and outputs the selected minimum value as the minimum limit value. This minimum limit value is input to the subtractor 441 as the maximum torque command limit value (first torque limit value) 440 based on the torque command for the motor 3.

[0050] In the subtractor 441, the drag torque 230 is subtracted from the input maximum torque command limit value (first torque limit value) 440, and the calculated subtraction value is output. This subtraction value is input to the second minimum value selection unit 402 as the maximum shaft torque limit value (second torque limit value) 450 based on the shaft torque output by the motor 3.

[0051] In addition, constraint elements 410 and 420 are illustrated using separate elements, but they can also be multiple elements, examples of which will be described later. Figure 7 The description is incomplete. Furthermore, the drag torque of 230 is... Figure 7 The drag torque mapping 740 shown is determined in a form that obtains a specified accuracy through speed information, DC voltage, etc., and can be obtained by equations, for example.

[0052] The second minimum value selection unit 402 acquires the input maximum shaft torque limit value (second torque limit value) 450, and the communication function unit 110 obtains the torque command T. The result of checking for outliers and missing data is torque command 460. These values ​​are compared and the smallest value is selected, thereby calculating the restricted torque command 470 after adding the restrictions of restriction elements 410 and 420 to torque command 460.

[0053] Adder 471 adds drag torque 230 to the limited torque command 470 calculated by the second minimum value selection unit 402, thereby performing drag torque compensation for correcting the physical losses of motor 3, and calculating final torque command 480.

[0054] The torque command determination unit 140 outputs the calculated final torque command value 480 to the current control unit 130. Based on this final torque command value 480, the current control unit 130 outputs the gate signal 490 to the power conversion circuit 7, thereby enabling the motor 3 to operate within a specified torque range and maximizing the available torque.

[0055] ( Figure 6 )

[0056] use Figure 6 (a) ~ Figure 6 (c) will be used to illustrate action points 520a to 520c. Figure 5 The decision logic of the torque command determination unit 140.

[0057] Figure 5 The torque command 470 before drag torque compensation corresponds to the torque limitation command 470. Figure 6 (a) The torque command action point 520a. The final torque command 480, after compensation by adding the drag torque 230 to the limited torque command 470 by the adder 471, is the same as... Figure 6 (b) The torque command action point 520b corresponding to the speed-torque action range 600 after adding the drag torque. These torque command action points 520a and 520b correspond to the command of the upper limit of torque.

[0058] Current control unit 130 based on Figure 1 The phase detection device 4 and phase detection unit 170, the current detection device Ict and current detection unit 160, and the DC voltage detection unit (not shown) are used to calculate the current and voltage that output the torque following the final torque command 480 input from the torque command determination unit 140, based on the operating state of the motor 3. The current control unit 130 sends a gate drive signal 490 based on the calculated current and voltage to the power conversion circuit 7. The power conversion circuit 7 determines the switching mode of the semiconductor devices it possesses based on the input gate drive signal 490 and drives the motor 3.

[0059] Motor 3 generates torque through three-phase currents Iu, Iv, and Iw. However, due to losses such as mechanical losses, the output is a shaft torque that corresponds to the torque command 470 before torque compensation, but with a reduction of the drag torque 230 from the final torque command 480. In this case, assuming the torque command is not limited by overheating, the maximum shaft torque limit 450 calculated by subtractor 441 is larger than the torque command 460. Therefore, torque limitation is not performed in the second minimum value selection unit 402, and instead, torque command 460 is selected as the minimum value. As a result, torque command 460 is consistent with the torque command 470 after limitation, and therefore, the final shaft torque output from motor 3 is basically consistent with torque command 460. This corresponds to... Figure 6 (c) When the upper limit of torque is reached, the shaft torque action point 520c is output from motor 3.

[0060] Therefore, considering calculations based on different bases, such as calculations related to temperature protection and calculations related to voltage limits, by subtracting the amount of drag torque in the stage before determining the limit value, it is possible to unify and coexist the concept of limit values ​​with different calculation ideas. Furthermore, by adding drag torque to the torque command after limiting it for compensation, it is possible to use the output limit of motor 3 without over-protection, thus achieving both improved torque accuracy and reliable protection during operation at maximum torque.

[0061] ( Figure 7 )

[0062] Figure 7 Is Figure 1 and Figure 5 The power conversion control device 100 of the present invention shown is an example of a plurality of limiting elements 410 that are input to the first minimum value selection unit 201 of the torque command determination unit 140 via the component protection function unit 150.

[0063] The protection function unit 150 has a first torque limit value mapping 700 related to the motor overheat protection function, a second torque limit value mapping 710 related to the component overheat protection function, and a third torque limit value mapping 720 related to the speed-torque operating range limit.

[0064] Motor temperature detection unit 180 based Figure 1 The temperature information of the motor 3 detected by the motor temperature detection device 5 shown is output to the first torque limit value mapping 700 of the protection function unit 150.

[0065] The current detection unit 160 will be based on Figure 1The current detection device Ict detects the three-phase AC current information Iu, Iv, and Iw, and the calculated values ​​are output to the first torque limit value mapping 700 and the second torque limit value mapping 710. The DC voltage detection unit 161 will output the values ​​based on the information Iu, Iv, and Iw of the three-phase AC current. Figure 1 The value calculated from the DC voltage detected by the sensor (not shown) is output to the first torque limit value map 700 and the second torque limit value map 710.

[0066] like Figure 1 As shown, the component temperature detection unit 120 acquires temperature information output from the circuit temperature detection device 8 that detects the temperature of the power conversion circuit 7 and the X capacitor temperature detection device 9 that detects the temperature of the X capacitor 6, and inputs the value based on the temperature information into the second torque limit value mapping 710.

[0067] The phase detection unit 170 inputs the phase information of the motor 3 obtained from the phase detection device 4 to the speed calculation unit 171. The speed calculation unit 171 calculates the rotational speed of the motor 3 based on the phase information and inputs it to the third torque limit value mapping 720.

[0068] The torque limit value mapping 700 is a torque limit value mapping composed of the motor temperature obtained by thermistors to prevent the motor from overheating, the current value to compensate for the thermal response delay of the thermistors, and the temperature, current and voltage considering that the generated losses depend on the DC voltage.

[0069] The torque limit value mapping 700 calculates the torque limit value 410a related to the motor overheat protection function and outputs it to the first minimum value selection unit 201 of the torque command determination unit 140. This torque limit value 410a serves as... Figure 5 The limiting element 410 is input to the first minimum value selection unit 201. Furthermore, the method for calculating this torque limiting value 410a can be other implementation methods such as using the thermal loop equation, and it is not necessary to use a mapping form.

[0070] The torque limit value mapping 710 calculates the torque limit value 410b related to the component overheat protection function and outputs it to the first minimum value selection unit 201 of the torque command determination unit 140. This torque limit value 410a serves as... Figure 5 The limiting factor 410 is input to the first minimum value selection unit 201. Before actual measurement, these mappings are usually set to initial values ​​with a corresponding margin. At this time, since there is no data on the drag torque, the determination is based on the torque command.

[0071] The torque limit value mapping 720 is a mapping determined according to the motor specifications. It calculates a torque limit value 420 related to the speed-torque operating range limitation and outputs it to the first minimum value selection unit 201. The calculated torque value is defined by the shaft torque. This torque limit value 420 serves as... Figure 5 The limiting element 420 is input to the first minimum value selection unit 201.

[0072] The drag torque mapping 740 adds the drag torque amount to the torque limit value 420 output from the torque limit value mapping 720 to the minimum value selection unit 201 and the torque command 460 output from the communication function unit 110 to the minimum value selection unit 201. Furthermore, with Figure 5 Similarly, the drag torque mapping 740 subtracts the drag torque 230 from the maximum torque command limit 440 and adds the drag torque 230 to the limited torque command 470.

[0073] (Modified example)

[0074] Although not illustrated, the following situation will be explained: If a vehicle or motor 3 malfunctions, it will enter a protection state to avoid operating at maximum torque, even when the torque is sufficient for backing up or other maneuvers.

[0075] For example, consider the following situation: the limit element 420 based on shaft torque is smaller than usual, and operation is restricted. In this case, for the limit element 420 based on shaft torque, for example, the motor 3 is restricted to 50% of its normal torque output, and if the torque command 460 is larger than the 50% output limit value, the maximum torque command limit 460 is calculated by adding the amount of drag torque to the torque command limit value of 50%.

[0076] Then, the amount of drag torque is subtracted from the maximum torque command limit 440, and then compared with the torque command 460 in the second minimum value selection unit 402, thereby calculating the limited torque command 470 by the second minimum value selection unit 402. This limited torque command 470 is consistent with the maximum torque command limit 440 obtained by adding the amount of drag torque to the limit element 420 based on shaft torque.

[0077] Subsequently, the amount of drag torque is added to the torque-limited command 470 for compensation, and the motor 3 is controlled based on the final torque command 480. The final output torque T will reduce the amount of drag torque. That is, if control error is excluded, the torque-limited command 470 is consistent with the limiting element 420 based on shaft torque.

[0078] When the protection-related limiting torque is defined by a torque command, the limiting element 410 input to the first minimum value selection unit 201, which is based on the torque command, becomes a torque limiting value of 50% or similar. Instead of adding the drag torque, it is directly adopted as the torque limiting value of the maximum torque command limiting 440. Subsequent processing is the same as in the case of a limitation based on shaft torque. Thus, the same effect as in Embodiment 1 can be achieved.

[0079] (Implementation Method 2)

[0080] ( Figure 8 )

[0081] In this invention, separate independent limiting logic, namely torque command reference independent limiting logic 840 and shaft torque reference independent limiting logic 850, can be set in the respective simulation ranges of the maximum torque command limit value 440 and the maximum shaft torque limit value 450, as needed.

[0082] For example, when the torque command reference independent limit logic 840 is inserted within the analog range of the maximum torque command limit value 440, the torque command reference independent limit logic 840 adds a new limit to the minimum limit value 440a output from the first minimum value selection unit 201 based on the torque command, thereby calculating the maximum torque command limit value (first torque limit value) 440. In the subtractor 441, the drag torque 230 is subtracted from the maximum torque command limit value (first torque limit value) 440, thereby calculating the subtraction value 450a.

[0083] Furthermore, when the shaft torque reference independent limit logic 850 is inserted within the analog range of the maximum shaft torque limit value 450, the shaft torque reference independent limit logic 850 adds a new limit to the subtraction value 450a output from the subtractor 441 based on the shaft torque, thereby enabling the calculation of the maximum shaft torque limit value (second torque limit value) 450.

[0084] Additionally, new restrictions added by the shaft torque-based independent limiting logic 850 are, for example, restrictions that control the behavior of vehicle or structural components.

[0085] Therefore, through software construction, the calculation processing of the maximum torque command limit value 440 based on the torque command and the calculation processing of the maximum shaft torque limit value 450 based on the shaft torque can be set up as separate structures. Thus, the torque command reference independent limit logic 840 and the shaft torque reference independent limit logic 850, which are independent control logics, can be easily inserted even after their respective calculation processing, without needing to reconstruct the existing processing structure based on the assumed input torque limit reference. Therefore, mappings that are difficult to change due to customer-generated control, etc., can be directly integrated into the processing using the existing logic.

[0086] Furthermore, this allows for shorter design times through independent development and facilitates the easy implementation of encryption logic. Additionally, it enables hardware protection in case of temperature increases or sensor failures.

[0087] In addition, such as Figure 8 As shown, the torque command reference independent limit logic 840 and the shaft torque reference independent limit logic 850 can both be inserted into the analog range, or only one of them can be inserted.

[0088] With only the torque command reference independent limit logic 840 inserted, the drag torque 230 is subtracted from the maximum torque command limit value (first torque limit value) 440 calculated by the torque command reference independent logic 840 via the subtractor 441, thereby obtaining the subtraction value 450a. This subtraction value 450a is directly input to the second minimum value selection unit 402 as the maximum shaft torque limit value (second torque limit value) 450.

[0089] On the other hand, when only the shaft torque reference independent limiting logic 850 is inserted, the minimum limiting value 440a output from the first minimum value selection unit 201 is directly input to the subtractor 441 as the maximum torque command limiting value (first torque limiting value) 440. In the shaft torque reference independent limiting logic 850, the maximum shaft torque limiting value (second torque limiting value) 450 can be calculated by subtraction value 450a calculated by the subtractor 441 based on the maximum torque command limiting value (first torque limiting value) 440.

[0090] According to the embodiments of the present invention described above, the following effects are achieved.

[0091] (1) The motor control device 100 includes: a first torque limit value calculation unit, which calculates a first torque limit value 440 based on a torque command in order to make the motor 3 operate within a specified torque range, based on a first limit element 420 based on the shaft torque output by the motor 3 and a second limit element 410 based on the torque command for the motor 3; a second torque limit value calculation unit, which calculates a second torque limit value 450 based on the shaft torque based on a subtraction value obtained by subtracting the drag torque corresponding to the physical loss of the motor 3 from the first torque limit value 440; and a final torque command value calculation unit, which calculates a final torque command value 480 after compensating for the drag torque 230 based on the second torque limit value 450 and the torque command value 460 input from the outside. The first torque limit calculation unit compares the value obtained by adding the drag torque to the first limit element 420 with the second limit element 410, selects the smaller value as the minimum limit value, and calculates the first torque limit value 440 based on the selected minimum limit value. The final torque command value calculation unit compares the second torque limit value 450 and the torque command value 460, selects the smaller value, and adds the drag torque to the selected value to calculate the final torque command value 480. Thus, even when implementing output limits with different references, appropriate output limits and maximization of the available torque output can be achieved.

[0092] (2) The first torque limit value calculation unit adds a new limit to the minimum limit value 440a based on the torque command, and calculates the value obtained therefrom as the first torque limit value 440. Thus, it is possible to add a limit 840 based on the torque command that includes other requests to the value after the reference has been unified with the output limit that has a different reference.

[0093] (3) The second torque limit value calculation unit adds a new limit to the subtraction value 450a based on the shaft torque, and calculates the value obtained therefrom as the second torque limit value 450. Thus, it is possible to add a limit 850 based on the shaft torque that includes other requests to the value after the reference has been unified with the output limit of different reference.

[0094] (4) The first torque limit calculation unit adds a new limit to the minimum limit value 440a based on the torque command 840, and calculates the value obtained therefrom as the first torque limit value 440. The second torque limit calculation unit adds a new limit 850 to the subtraction value based on the shaft torque, and calculates the value obtained therefrom as the second torque limit value 450. Thus, it is possible to calculate the limit value obtained after unifying and coexisting the concept of limit values ​​that make different calculation concepts.

[0095] (5) In the second torque limit value calculation section, the newly added limit based on shaft torque is a limit on the behavior of the vehicle or the structural component of the electric motor equipped with the electric motor control device 100. As a result, appropriate protection can be implemented.

[0096] Furthermore, the present invention is not limited to the embodiments described above, and various modifications or combinations of other structures can be made without departing from its spirit. Additionally, the present invention is not limited to having all the structures described in the above embodiments, but also includes structures obtained by deleting a portion of those structures.

[0097] Label Explanation

[0098] 1. Electric motor drive system

[0099] 2 batteries

[0100] 3. Electric motor

[0101] 4. Phase detection device

[0102] 5. Motor temperature detection device

[0103] 6 X capacitors

[0104] 7 Power Conversion Circuit

[0105] 8. Circuit temperature detection device

[0106] 9X Capacitor Temperature Detection Device

[0107] 100 Power Conversion Control Device

[0108] 110 Communications Functional Department

[0109] 120 Component Temperature Detection Section

[0110] 130 Current Control Unit

[0111] 140 Torque Command Determination Unit

[0112] 150 Component Protection Function Section

[0113] 160 Current Detection Unit

[0114] 161 DC Voltage Detection Department

[0115] 170 Phase Detection Unit

[0116] 171 Speed ​​Calculation Department

[0117] 180 Electric Motor Temperature Detection Section

[0118] 190 Retreat Driving Judgment Unit

[0119] 201 First Minimum Value Selection Section

[0120] 220 Torque command value

[0121] 230 drag torque

[0122] 402 Second Minimum Selection Section

[0123] 410 Second limiting element

[0124] 410a First torque limit value

[0125] 410b Second Torque Limit Value

[0126] 420 First limiting element

[0127] 421 Adder

[0128] 430 Limitations on converting from shaft torque reference to torque command reference

[0129] 440 Maximum torque command limit (first torque limit)

[0130] 441 Subtractor

[0131] 450 Maximum shaft torque limit (second torque limit)

[0132] 460 Torque command value

[0133] 470 Torque command value after limitation

[0134] 471 Adder

[0135] 480 Final torque command value

[0136] 490 Gate drive signal

[0137] 500 Torque Limiter

[0138] 600 RPM - Torque Activation Range after Adding Driving Torque

[0139] Torque limit under the torque reference of shaft 601

[0140] 700 First Torque Limit Value Mapping

[0141] 710 Second Torque Limit Value Mapping

[0142] 720 Third Torque Limit Value Mapping

[0143] 740 Drag Torque Mapping

[0144] 840 Torque Command Reference Independent Limitation Logic

[0145] 850-axis torque reference independent limiting logic

[0146] I Current

[0147] T torque

[0148] Ict current detection device

[0149] Iu, Iv, Iw three-phase currents

[0150] T Torque command

[0151] TLim is the torque limit value.

Claims

1. An electric motor control device characterized by comprising: comprises: a first torque limit value calculation section that calculates a first torque limit value based on a first limit element that is based on a shaft torque output by the motor and a second limit element that is based on a torque command for the motor, in order to operate the motor within a prescribed torque range; a second torque limit value calculation section that calculates a second torque limit value based on a subtraction value obtained by subtracting an amount of a drag torque corresponding to a physical loss of the motor from the first torque limit value; and a final torque command value calculation section that calculates a final torque command value after compensation for the drag torque based on the second torque limit value and a value of the torque command input from the outside, the first torque limit value calculation section compares a value obtained by adding the amount of the drag torque to the first limit element and the second limit element, selects a minimum limit value from among the minimum limit values, and calculates the first torque limit value based on the selected minimum limit value, the final torque command value calculation section compares the second torque limit value and the value of the torque command, selects a value of the smaller one, and calculates the final torque command value by adding the amount of the drag torque to the selected value.

2. The motor control device according to claim 1, wherein the first torque limit value calculation section newly adds a limit to the minimum limit value based on the torque command, and calculates a value obtained thereby as the first torque limit value.

3. The motor control device according to claim 1, wherein the second torque limit value calculation section newly adds a limit to the subtraction value based on the shaft torque, and calculates a value obtained thereby as the second torque limit value.

4. The motor control device according to claim 1, wherein the first torque limit value calculation section newly adds a limit to the minimum limit value based on the torque command, and calculates a value obtained thereby as the first torque limit value, the second torque limit value calculation section newly adds a limit to the subtraction value based on the shaft torque, and calculates a value obtained thereby as the second torque limit value.

5. The motor control device according to claim 3 or 4, wherein the limit newly added based on the shaft torque in the second torque limit value calculation section is a limit that controls behavior of a structural member of a vehicle or the motor on which the motor control device is mounted.

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