Control apparatus of electric drive system

Abstract

To suppress a restriction of an input power to a dynamo-electric motor in order to maintain a desired output of a dynamo-electric motor by searching for a condition that a component of the dynamo-electric motor is thermally protected.SOLUTION: A control apparatus of an electric drive system is for calculating an input command value for instructing a command to a power conversion device in order to drive a dynamo-electric motor at a desired operation point. The control apparatus of the electric drive system performs a prediction calculation of a current waveform component of a power input into the dynamo-electric motor in accordance with the input command value, a prediction calculation of a loss generated in a plurality of components of the dynamo-electric motor from the current waveform component, a prediction calculation of a temperature of the plurality of component of the dynamo-electric motor on the basis of the loss, and an output of the input command value which is corrected in the case where a prediction temperature of at least one of the dynamo-electric motor exceeds each management temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for an electric drive system of an automobile or the like. [Background technology]

[0002] Due to the growing awareness of global environmental protection, the automotive industry is also shifting from conventional internal combustion engine drive to electric drive using electric motors that do not emit greenhouse gases during operation. Electric drive systems, which are essential for the electrification of automobiles, are equipped with a power converter, an electric motor, and a control device that controls them in order to extract driving force from the power supplied from the battery. In an electrically driven automobile, the vehicle driving performance such as acceleration / deceleration, maximum speed, and continuous driving characteristics is the same as that of an internal combustion engine. Unlike an internal combustion engine, an electric motor does not require management of combustion temperature, but losses occur in each component in the process of converting electrical energy into rotational power using an electromagnetic circuit. This loss causes the components to heat up, and depending on the component, it may cause irreversible performance degradation. In particular, during continuous driving, the components continue to heat up and generate losses, so the performance of the electric motor is restricted to suppress the rise in the component temperature. To thermally protect the components of an electric motor, a temperature sensor is generally attached to the coil end, and the conditions under which the temperature of each component does not exceed the respective set management temperature are obtained by analysis, etc. Then, when the temperature sensor value reaches a preset threshold value so that the temperature of each component does not exceed the control temperature, the input to the motor is limited, thereby preventing an increase in loss in the motor while it is running, thereby suppressing heat generation from the components.

[0003] As an example of this type, Patent Document 1 discloses a method in which losses occurring in an electric motor are calculated from the difference between the input and output of the motor, and when the estimated temperature of the motor calculated by accumulating these losses exceeds a threshold value, the input power to the motor is limited to prevent the motor from overheating.

[0004] Furthermore, Patent Document 2 discloses a method of minimizing losses by comparing losses in one-pulse control and other control methods and selecting the method that results in smaller losses. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO 17 / 126093 [Patent Document 2] International Publication No. 08 / 107992 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the method disclosed in Patent Document 1, the input power to the motor is limited to thermally protect the components, making it difficult to continuously drive the motor at a desired operating point. In addition, in the method disclosed in Patent Document 2, although the loss of the motor is suppressed, in situations where the loss that cannot be thermally protected from the motor at the desired operating point is unavoidable, the operating point of the motor must be lowered and the input power of the motor must be limited, as in the method of Patent Document 1, making it difficult to drive the motor at a desired operating point according to the operation.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a control device for an electric drive system that can search for conditions under which the components of an electric motor are thermally protected, and suppress limitations on the input power to the electric motor in order to maintain a desired output from the electric motor. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides a control device for an electric drive system that calculates an input command value to be issued to a power converter, which converts power of a power source and outputs input power to an electric motor, in order to drive the motor at a desired operating point, the control device comprising: a current waveform component calculation unit that predicts and calculates a current waveform component of power input from the power converter to the electric motor when the calculated input command value is output; a motor component loss calculation unit that predicts and calculates losses that will occur in a plurality of components of the electric motor when the input command value is output, from the current waveform component calculated by the current waveform component calculation unit; and a motor component temperature calculation unit that predicts and calculates temperatures of the plurality of components of the electric motor when the input command value is output, based on the losses calculated by the motor component loss calculation unit; and when the temperature of at least one component of the electric motor exceeds a predetermined management temperature, the control device corrects the input command value and outputs the corrected input command value to the power converter so that the temperature of the at least one component of the electric motor becomes equal to or lower than the management temperature. Effect of the Invention

[0009] According to the present invention, it is possible to search for a condition where the components of the motor are thermally protected, and to suppress the limitation of the input power to the motor in order to maintain a desired output of the motor. [Brief description of the drawings]

[0010] [Figure 1] 1 is a functional block diagram illustrating a main part of a control device for an electric drive system according to a first embodiment of the present invention. [Diagram 2] FIG. 10 is an explanatory diagram of a specific example of the input command value correction process performed by the control device of the electric drive system according to the first embodiment of the present invention, and is a diagram showing component losses of the electric motor predicted for the input command value before correction. [Diagram 3] FIG. 10 is an explanatory diagram of a specific example of the input command value correction process performed by the control device of the electric drive system according to the first embodiment of the present invention, and is a diagram showing the temperatures of electric motor components predicted for the input command value before correction. [Figure 4]FIG. 10 is an explanatory diagram of a specific example of the input command value correction process performed by the control device of the electric drive system according to the first embodiment of the present invention, and is a diagram showing the temperatures of electric motor components predicted for the corrected input command value. [Diagram 5] FIG. 10 is an explanatory diagram of a specific example of the input command value correction process performed by the control device of the electric drive system according to the first embodiment of the present invention, and is a diagram showing a comparison of predicted temperatures of electric motor components before and after correction of the input command value. [Figure 6] FIG. 6 is a functional block diagram illustrating a main part of a control device for an electric drive system according to a second embodiment of the present invention. [Figure 7] FIG. 11 is an image diagram of a torque improvement effect obtained by applying the second embodiment of the present invention. [Figure 8] FIG. 11 is a functional block diagram illustrating a main part of a control device for an electric drive system according to a third embodiment of the present invention. [Figure 9] FIG. 11 is a functional block diagram illustrating a main part of a control device for an electric drive system according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] (First embodiment) -Electric drive system- FIG. 1 is a functional block diagram showing the main components of a control device for an electric drive system according to a first embodiment of the present invention.

[0013] The electric drive system of this embodiment is installed in an electric vehicle or a hybrid vehicle, and includes a control device 101, a power converter 102, and an electric motor 103.

[0014] The control device 101 is a computer, and includes an arithmetic device such as a CPU, and memories such as a RAM and a ROM. A value related to an operating point of the electric motor 103 (rotation speed and torque of the electric motor 103) calculated separately in response to the operation of an operating device (accelerator, brake, shift lever, etc.) is input to the control device 101. The control device 101 calculates an input command value to be issued to the power converter 102 in accordance with a program stored in the memory, and outputs the input command value to the power converter 102 so that the electric motor 103 is driven at the input operating point.

[0015] The power converter 102 is, for example, an inverter, which converts the power of a power source (not shown) such as a battery or generator mounted on the electric vehicle based on an input command value from the control device 101 so that the power can be supplied to the electric motor 103, and inputs the converted power to the electric motor 103. Of the power input to the electric motor 103, the current is proportional to the torque of the electric motor 103, and the voltage is proportional to the rotation speed. The type of the power converter 102 is not particularly limited.

[0016] The electric motor is, for example, an AC electric motor, and is driven by power input from the power converter 102 to run the electric vehicle. Although not shown in Fig. 1, the output of the electric motor 103 is transmitted to the axle via a reduction gear in an electric vehicle. In a hybrid vehicle, the output is transmitted to the axle via a transmission or a power split mechanism. The type of the electric motor 103 is not particularly limited.

[0017] -Control device- The control device 101 includes a control unit 111, a current waveform component calculation unit 112, a motor component loss calculation unit 113, a motor component temperature calculation unit 114, and a loss / temperature comparison unit 115. The control unit 111, the current waveform component calculation unit 112, the motor component loss calculation unit 113, the motor component temperature calculation unit 114, and the loss / temperature comparison unit 115 are hardware elements such as circuits that execute the respective processes, or software elements such as programs.

[0018] Control unit The control unit 111 calculates an input command value to the power converter 102 for driving the electric motor 103 at a desired operating point.

[0019] ·Current waveform component calculation unit The current waveform component calculation unit 112 predicts and calculates components (e.g., fundamental wave components, n-th order current In, d-axis component Idn of n-th order current, q-axis component Iqn of n-th order current, order n of n-th order current, etc.) included in the current waveform of the power input from the power converter 102 to the motor 103 when the input command value calculated by the control unit 111 is output without correction. The method of calculating the current waveform components in the current waveform component calculation unit 112 is not particularly limited, but for example, a map of dq-axis inductance for each operating point is stored in a memory, and the d-axis current and q-axis current at the input operating point can be calculated. In addition, the current waveform component calculation unit 112 has a function of correcting the input command value (e.g., the current phase of the input command value or the carrier frequency) according to the calculation results of the electric motor component loss calculation unit 113, the electric motor component temperature calculation unit 114, and the loss / temperature comparison unit 115 in the subsequent stages, and outputting the corrected value to the control unit 111.

[0020] Motor component loss calculation section The motor component loss calculation unit 113 predicts and calculates losses that will occur in a plurality of temperature-controlled components (e.g., coils and permanent magnets) of the motor 103 when the input command value calculated by the control unit 111 is output without correction, based on the current waveform components calculated by the current waveform component calculation unit 112. There is no particular limitation on the method of calculating the component losses of the motor 103 in the motor component loss calculation unit 113. One example of the calculation method is to prepare a loss map in which the losses of each temperature-controlled component are calculated by electromagnetic field analysis for each operating point of the motor 103, store the loss in memory, and perform two-dimensional interpolation of the losses of each temperature-controlled component at the input operating point. Other examples of the calculation method include a method that uses an approximation formula based on the results of electromagnetic field analysis of the motor 103, or an empirical formula obtained based on data actually measured by a measuring instrument for the motor 103. The loss calculation formula is constructed, for example, using the rotation frequency of the motor 103, the current harmonic components and their orders and coefficients, etc.

[0021] Motor component temperature calculation unit Based on the losses of each temperature-controlled component of motor 103 calculated by motor component loss calculation unit 113, motor component temperature calculation unit 114 predicts and calculates the temperatures of those temperature-controlled components of motor 103 when the input command value calculated by control unit 111 is output without correction. The method of calculating the component temperatures of motor 103 in motor component temperature calculation unit 114 is not particularly limited, and as an example, the component temperatures can be calculated using a thermal calculation tool based on a thermal circuit network. Also, the component temperatures can be calculated using a thermal fluid analysis tool.

[0022] ·Loss / temperature comparison section The loss / temperature comparison unit 115 compares the loss of each temperature-controlled component of the motor 103 calculated by the motor component loss calculation unit 113 and the temperature of each temperature-controlled component of the motor 103 calculated by the motor component temperature calculation unit 114 with the characteristic curve (characteristic curve of loss and temperature against current condition) previously stored in memory for each temperature-controlled component and the control temperature previously set for each temperature-controlled component and stored in memory. The control temperature differs for each temperature-controlled component. For example, there are some components, such as the conductor constituting the coil, whose control temperature is set according to a predetermined heat resistance grade, and there are also some components, such as permanent magnets, whose control temperature is set to a temperature that does not cause irreversible thermal demagnetization. For example, when a material that is easily degraded in performance under high heat, such as recycled magnets, is used, the control temperature is set taking this into consideration.

[0023] If the comparison by loss / temperature comparison unit 115 shows that the temperature of at least one of the multiple temperature-controlled components of electric motor 103, whose losses and temperatures have been predicted and calculated, exceeds the corresponding controlled temperature, the input command value is corrected by current waveform component calculation unit 112 and output to control unit 111 so that the temperature of the at least one temperature-controlled component that exceeds the controlled temperature becomes equal to or lower than the corresponding controlled temperature, and the corrected input command value is output to power converter 102 via control unit 111.

[0024] At that time, the corrected input command value may be processed by current waveform component calculation unit 112, motor component loss calculation unit 113, motor component temperature calculation unit 114, and loss / temperature comparison unit 115, and after confirming that there are no temperature-controlled parts in motor 103 that exceed the control temperature, the corrected input command value may be output to control unit 111. Note that, for the input command value calculated by control unit 111, if there are no temperature-controlled parts in motor 103 that exceed the control temperature, the input command value calculated by control unit 111 is output from current waveform component calculation unit 112 to control unit 111 without being corrected.

[0025] -Example of correction- 2 to 5 are explanatory diagrams of specific examples of input command value correction processing by the control device 101. FIG. 2 is a diagram showing losses in temperature-controlled parts (here, a coil jump permanent magnet is shown as an example) of the electric motor 103 predicted for an input command value before correction at a certain operating point calculated according to an operation. FIG. 3 is a diagram showing temperatures of the temperature-controlled parts of the electric motor 103 predicted for an input command value before correction under the conditions of FIG. 2. FIG. 4 is a diagram showing temperatures of the temperature-controlled parts of the electric motor 103 predicted for an input command value after correction under the conditions of FIG. 2. FIG. 5 is a diagram showing a comparison of predicted temperatures of the temperature-controlled parts of the electric motor 103 before and after correction of the input command value.

[0026] In this embodiment, for example, if it is expected that a temperature-controlled component of the motor 103 will exceed the control temperature when the input command value calculated by the control unit 111 according to the operating point is output without correction, the current input condition (e.g., current phase) of the input command value is changed, and the condition under which the loss of the temperature-controlled component exceeding the control temperature is minimized is calculated based on, for example, a characteristic line that specifies the relationship between the current input condition and component loss.

[0027] In control unit 111, as shown in Fig. 2, an input command value is determined based on a characteristic line at an operating point of electric motor 103 according to an operation under conditions where loss in a given temperature-controlled part (coil in the example of Fig. 2) with strict temperature constraints is minimized. Therefore, for other temperature-controlled parts (permanent magnets in the example of Fig. 2), the loss may not be minimized with the input command value calculated by control unit 111. This calculation of part loss is executed by electric motor part loss calculation unit 113.

[0028] When the component temperatures are calculated using the characteristic curves between the current conditions and the component temperatures for the example shown in Fig. 2, if the input command value calculated by the control unit 111 is output without correction, the coil temperature is expected to fall below the management temperature, but the permanent magnet temperature is expected to exceed the management temperature, as shown in Fig. 3. Such calculations of component temperatures and comparisons with the management temperatures are performed by the motor component temperature calculation unit 114 and the loss / temperature comparison unit 115, as described above.

[0029] However, like the loss shown in Fig. 2, the temperature of the permanent magnet does not become a minimum under the conditions of the input command value calculated by control unit 111, and there is a margin for reduction at the same operating point. The temperature of the permanent magnet becomes a minimum when the current input condition of the input command value is moved to the left (the current phase is delayed) on the characteristic line of the operating point in Fig. 3. Therefore, in this embodiment, the correction function of current waveform component calculation unit 112 corrects the current input condition (current phase) of the input command value so that the temperature of the permanent magnet becomes a minimum at the operating point in Fig. 3.

[0030] When the temperatures of the temperature-controlled parts are calculated again under these corrected conditions, it is expected that the temperature of the permanent magnet will be lower than the control temperature, and the temperature of the coil will also be kept lower than the control temperature, as shown in Fig. 4. As shown in Fig. 5, under the corrected input command value conditions, compared to the conditions of the input command value before correction, the temperature of one of the multiple temperature-controlled parts of the motor 103 (the permanent magnet in this example) that exceeded the control temperature under the conditions before correction will fall by ΔT1 to below the control temperature, while the temperature of another temperature-controlled part (the coil in this example) that was originally below the control temperature may rise by ΔT2, but a condition can be found where the temperatures of all of the temperature-controlled parts are below the control temperature.

[0031] If a current input condition is found under which the temperature of any of the temperature-controlled components does not exceed the controlled temperature, the motor 103 can be continuously driven without changing the operating point (under the operating point characteristics of Figures 2-5).

[0032] If correcting the input conditions causes a further different temperature control component to exceed the control temperature, the correction is repeated and the temperature of each temperature control component is recalculated, for example by correcting to conditions that minimize the loss of the temperature control component that newly exceeds the control temperature. If there is no current input condition that keeps all temperature control components at or below the control temperature (for example, if the condition is not satisfied even after repeating the correction a set number of times, or if the condition is not satisfied even after attempting correction under conditions that minimize the loss for all temperature control components), in that case the operating point is lowered by a specified amount and the above process, such as the calculation of component temperatures, is repeated.

[0033] In this example, the current phase is corrected as the current input condition of the input command value, but the current input condition to be corrected is not limited to the current phase. For example, the carrier frequency of the input command value can also be corrected. The modulation method in the control unit 111 is not particularly limited, and for example, a three-phase modulation method or a two-phase modulation method can be applied.

[0034] -effect- (1) According to this embodiment, the component loss and component temperature of the electric motor 103 are predicted and calculated for the input command value calculated according to the desired operating point, and when there is a temperature-controlled component that exceeds the management temperature, the current condition of the input command value to the power converter is corrected so that the temperature of each temperature-controlled component becomes equal to or lower than the respective management temperatures without changing the operating point. As a result, at an operating point where any of the temperature-controlled components of the electric motor 103 exceeds the management temperature and the electric motor 103 cannot be driven, the input command value to the power converter 102 is corrected, so that the electric motor 103 can be driven at a desired operating point while suppressing the component temperature of the electric motor 103 to or lower than the management temperature without restricting the input power to the electric motor 103. In the input command value after correction, the temperature of the components other than the temperature-controlled components that suppress the loss is not the minimum value. Therefore, the temperature rises compared to when the input command value is not corrected, and the overall loss of each temperature-controlled component does not necessarily decrease compared to before the correction, and in some cases, the correction may increase the overall loss. However, by searching for conditions under which all temperature-controlled components are kept below the controlled temperature and avoiding limitations on the input power to the electric motor 103, it is possible to maintain the desired operating point and ensure the target torque of the electric motor 103.

[0035] As described above, according to this embodiment, it is possible to search for conditions under which the temperature management parts of the electric motor 103 are thermally protected, and to suppress limitations on the input power to the electric motor 103 in order to maintain the desired output of the electric motor 103.

[0036] (2) As an object of correction, the control device 101 corrects, for example, the current phase of the input command value. By advancing or delaying the phase of the input current to the electric motor 103, the balance of the dq-axis components of the current changes. This causes differences in the sensitivity of the copper loss of the coils and the magnet loss of the permanent magnets, so that the loss balance increases or decreases for each temperature-controlled component of the electric motor 103, and while the temperature of the temperature-controlled components that are within the controlled temperature under certain conditions increases, the temperature of the temperature-controlled components that exceed the controlled temperature decreases. This makes it possible to ensure the desired torque output of the electric motor 103 while thermally protecting the temperature-controlled components of the electric motor 103.

[0037] (3) As another example of a correction target, the carrier frequency of the input command value is corrected in the control device 101. By increasing the carrier frequency when calculating the input current to the electric motor 103, the harmonic components of the input current to the electric motor 103 are reduced, and the loss of the electric motor 103 is reduced overall. The reduction in loss also reduces the temperature of the components of the electric motor 103, and therefore, as described above, the desired torque output of the electric motor 103 can be secured while providing thermal protection for the temperature-controlled components of the electric motor 103.

[0038] Second embodiment Fig. 6 is a functional block diagram showing the main parts of a control device for an electric drive system according to a second embodiment of the present invention. Fig. 6 corresponds to Fig. 1. In Fig. 6, elements that are the same as or correspond to those in the first embodiment are given the same reference numerals as those in the previously mentioned drawings, and descriptions thereof will be omitted as appropriate.

[0039] The present embodiment differs from the first embodiment in that when the temperatures of all of the temperature-controlled components of the electric motor 103 fall below the controlled temperature, the torque of the operating point of the electric motor 103 is corrected to increase according to the difference between the controlled temperature and the predicted temperature.

[0040] In this embodiment, the input command value is corrected so that the temperature-controlled parts exceeding the control temperature are set to below the control temperature at the operating point where each temperature-controlled part can be thermally protected, as in the first embodiment. The difference is that when a margin is generated in the output torque of the electric motor 103 due to the correction of the input command value, the torque condition of the operating point that is the basis of the calculation of the input command value is raised by that amount, and the input command value is calculated again by the control unit 111 for the operating point where the torque is improved, and the processing of the current waveform component calculation unit 112, the electric motor component loss calculation unit 113, the electric motor component temperature calculation unit 114, and the loss / temperature comparison unit 115 is executed for the calculated input command value as in the first embodiment, and the newly calculated input command value is corrected as necessary, so that the electric motor 103 can be driven at a new operating point where the torque is higher than the desired operating point.

[0041] The basic configuration of the control device for the drive system is the same as in the first embodiment, but in the first embodiment, the configuration was such that the temperature of temperature control parts that exceeded the control temperature were lowered to provide thermal protection.

[0042] In other respects, this embodiment is similar to embodiment 1. As shown in Fig. 7, according to this embodiment, the electric motor 103 can be driven under a torque condition higher by the margin generated by the correction of the input command value.

[0043] The concept of operating point correction according to this embodiment can be combined with the following third and subsequent embodiments and modified examples.

[0044] Third embodiment Fig. 8 is a functional block diagram showing the main parts of a control device for an electric drive system according to a third embodiment of the present invention. Fig. 8 corresponds to Fig. 1 of the first embodiment. In Fig. 8, elements that are the same as or correspond to those in each of the previously described embodiments are given the same reference numerals as in the previously described drawings, and descriptions thereof will be omitted as appropriate.

[0045] The present embodiment differs from the first embodiment in that it further includes a converter component loss calculation unit 116. Converter component loss calculation unit 116 executes the same processing as motor component loss calculation unit 113 for power converter 102, and is hardware such as a circuit or software such as a program, similar to current waveform component calculation unit 112 and the like. Specifically, converter component loss calculation unit 116 predicts and calculates losses that will occur in each temperature-controlled component of power converter 102 when an input command value is output, from the current waveform component calculated by current waveform component calculation unit 112.

[0046] In this embodiment, the loss of each temperature-controlled component of the electric motor 103 calculated by the motor component loss calculation unit 113 and the loss of each temperature-controlled component of the power converter 102 calculated by the converter component loss calculation unit 116 are input to the loss vs. temperature comparison unit 115. In the loss vs. temperature comparison unit 115, for example, characteristic lines stored in a memory for each operating point of each temperature-controlled component of the electric motor 103 and the power converter 102, that is, the relationship between the current condition and the loss, are read. Then, in the current waveform component calculation unit 112, the input command value is corrected so that the sum of the loss of each temperature-controlled component of the electric motor 103 and the loss of each temperature-controlled component of the power converter 102 is minimized under the condition that the temperature of each temperature-controlled component of the electric motor 103 is below the respective control temperature. For example, the current waveform component calculation unit 112 compares the magnitude of the total loss of each temperature-controlled component of the electric motor 103 and the power converter 102 under a plurality of conditions under which the temperature of each temperature-controlled component of the electric motor 103 is below the respective control temperature, and selects the condition under which the total loss is minimized.

[0047] In other respects, this embodiment is similar to the first embodiment.

[0048] In this embodiment, in addition to obtaining the same effects as the first embodiment, it is possible to reduce losses in the entire electric drive system as much as possible.

[0049] The concept of minimizing the overall loss according to this embodiment can also be combined with the following fourth embodiment and modified examples.

[0050] (Fourth embodiment) Fig. 9 is a functional block diagram showing the main parts of a control device for an electric drive system according to a fourth embodiment of the present invention. Fig. 9 corresponds to Fig. 1 of the first embodiment. In Fig. 9, elements that are the same as or correspond to those in each of the previously described embodiments are given the same reference numerals as in the previously described drawings, and descriptions thereof will be omitted as appropriate.

[0051] The present embodiment differs from the first embodiment in that it further includes a converter component loss calculation unit 116 and a converter component temperature calculation unit 117. The converter component loss calculation unit 116 is the same as in the third embodiment. The converter component temperature calculation unit 117 executes the same processing as the motor component temperature calculation unit 114 for the power converter 102, and is hardware such as a circuit or software such as a program, similar to the current waveform component calculation unit 112 and the like. Specifically, the converter component temperature calculation unit 117 calculates the temperature of each temperature-controlled component of the power converter 102 when the input command value calculated by the control unit 111 is output, based on the loss of each temperature control of the power converter 102 calculated by the converter component loss calculation unit 116.

[0052] In this embodiment, the temperatures of each temperature-controlled component of the electric motor 103 calculated by the electric motor component temperature calculation unit 114 and the temperatures of each temperature-controlled component of the electric power converter 102 calculated by the converter component temperature calculation unit 117 are input to the loss / temperature comparison unit 115. The loss / temperature comparison unit 115 compares the temperatures of each temperature-controlled component of the electric power converter 102 calculated by the converter component temperature calculation unit 117 and the temperatures of each temperature-controlled component of the electric motor 103 calculated by the electric motor component temperature calculation unit 114 with the corresponding control temperatures. Then, when the predicted temperature of at least one of the temperature-controlled components of the electric power converter 102 and the electric motor 103 exceeds the corresponding control temperature, the input command value is corrected by the correction function of the current waveform component calculation unit 112 so that the predicted temperature of the at least one temperature-controlled component becomes equal to or lower than the corresponding control temperature. Thereafter, as in the first embodiment, the temperatures of each temperature-controlled component of the power converter 102 and the electric motor 103 are predicted and calculated under conditions after the input command value has been corrected as necessary, and when it is confirmed that the predicted temperatures of all the temperature-controlled components are below the controlled temperature, the corrected input command value is output to the power converter 102 via the control unit 111.

[0053] In other respects, this embodiment is similar to the first embodiment.

[0054] In this embodiment, in addition to obtaining the same effects as in the first embodiment, the entire electric drive system including not only the electric motor 103 but also the power converter 102 can be thermally protected.

[0055] (Modification) The present invention is not limited to the above-described embodiments, and may include various modified examples. For example, each embodiment does not necessarily have all the configurations described above. For example, a part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Also, in each embodiment, some of the configurations may be deleted or added. For example, the management temperature of each temperature-controlled part of the electric motor 103 may be changed rather than being a fixed value set uniformly for each part. For example, in each embodiment, the temperature lowered by the correction of the current input condition is set as the management temperature for each temperature-controlled part, so that the material of the temperature-controlled part can be replaced with one having a lower heat resistance. Heat resistance differs depending on the material even for the same type of temperature-controlled part. For example, in the case of a permanent magnet, the heat resistance decreases when a heavy rare earth-free permanent magnet in which the amount of heavy rare earth added is reduced or zero is adopted, so that the management temperature can be set low as described above. In addition, for coils, for example, when enameled copper wire manufactured by recycling used coils is adopted instead of a new product, the heat resistance decreases. By setting the temperature of each part lowered by the correction of the input command value as the management temperature as described above, a temperature-controlled part having a relatively lower heat resistance can be adopted. [Explanation of symbols]

[0056] 101...control device, 102...power converter, 103...motor, 111...control section, 112...current waveform component calculation section, 113...motor component loss calculation section, 114...motor component temperature calculation section, 115...loss / temperature comparison section, 116...converter component loss calculation section, 117...converter component temperature calculation section

Claims

1. A control device for an electric drive system, the control device calculating an input command value to be issued to a power converter that converts power of a power source and outputs input power to an electric motor so as to drive the electric motor at a desired operating point, a current waveform component calculation unit that predicts and calculates a current waveform component of the power input from the power converter to the electric motor when the calculated input command value is output; a motor component loss calculation unit that predicts and calculates losses that will occur in a plurality of components of the motor when the input command value is output, based on the current waveform components calculated by the current waveform component calculation unit; and a motor component temperature calculation unit that predicts and calculates temperatures of a plurality of components of the motor when the input command value is output based on the losses calculated by the motor component loss calculation unit, When the temperature of at least one component of the electric motor exceeds a preset management temperature, the input command value is corrected so that the temperature of the at least one component of the electric motor becomes equal to or lower than the management temperature, and the input command value is output to the power converter. A control device for an electric drive system.

2. The control device for an electric drive system according to claim 1, Under the corrected input command value, the temperature of the at least one component among the plurality of components of the electric motor decreases and the temperature of at least one of the other components increases, as compared with the input command value before correction. A control device for an electric drive system.

3. The control device for an electric drive system according to claim 1, A control device for an electric drive system, comprising: a control unit for correcting a current phase of the input command value.

4. The control device for an electric drive system according to claim 1, A control device for an electric drive system, comprising: a control unit for correcting a carrier frequency of the input command value.

5. The control device for an electric drive system according to claim 1, When any of the temperatures of a plurality of components of the electric motor falls below the management temperature, the torque of the operating point of the electric motor is corrected in an increasing direction according to a difference between the management temperature and the temperature. A control device for an electric drive system.

6. The control device for an electric drive system according to claim 1, a converter component loss calculation unit that predicts and calculates losses that will occur in a plurality of components of the power converter when the input command value is output, based on the current waveform components calculated by the current waveform component calculation unit; The input command value is corrected so that a sum of loss of the motor component and loss of the power converter component is minimized under a condition that the temperature of the at least one component of the motor is equal to or lower than the control temperature. A control device for an electric drive system.

7. The control device for an electric drive system according to claim 1, a converter component loss calculation unit that predicts and calculates losses that will occur in a plurality of components of the power converter when the input command value is output, based on the current waveform components calculated by the current waveform component calculation unit; and a converter component temperature calculation unit that calculates temperatures of components of the power converter when the input command value is output based on the loss calculated by the converter component loss calculation unit, When the temperature of at least one component of the power converter exceeds a preset management temperature, the input command value is corrected so that the temperature of the at least one component of the power converter becomes equal to or lower than the management temperature, and the input command value is output to the power converter. A control device for an electric drive system.

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