JP2018074646A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller which appropriately executes a current limitation in the case of reboot while suppressing a dark current during a drive stop period.SOLUTION: A substrate temperature storage unit 32, an outside air temperature storage unit 34 and a rise temperature storage unit 38 store a substrate temperature, an outside temperature and a rise temperature that is estimated by a rise temperature estimation unit 37, in the case of drive stop. In initial control in the case of reboot after drive stop of a motor 80 by a drive circuit 60, an initial rise temperature correction unit 401 uses a corrected substrate temperature difference ΔTs_comp (argument for correction) that is calculated based on a substrate temperature storage value Ts_m, a substrate temperature current value Ts, an outside temperature storage value Tg_m and an outside temperature present value Tg to correct a rise temperature storage value Ti_m and calculates an initial rise temperature correction value Ti_comp. The initial rise temperature correction unit 401 corrects a change from the outside air temperature storage value to the outside air temperature present value in such a manner that the initial rise temperature correction value Ti_comp is made smaller as a reduction degree from the substrate temperature storage value to the substrate temperature present value is relatively greater.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control device that controls energization of a motor.

2. Description of the Related Art Conventionally, in a motor controller that protects a motor or an element of a drive circuit by limiting the current based on a temperature rise estimated from the value of a current flowing through the motor or the drive circuit, a technique that focuses on temperature estimation during drive stop is known. It has been.
For example, the control device for the electric power steering apparatus disclosed in Patent Document 1 is configured so that the estimated temperature value of the motor does not become a predetermined value or less even when the ignition switch is turned off and a power stop signal is input. Is maintained and motor temperature estimation is continued.

JP 2002-363393 A

In the prior art of Patent Document 1, since a control power supply for temperature estimation is held (that is, power latch) for a predetermined period after the drive power supply is stopped, there is a problem that dark current during drive stoppage increases. .
In addition, when a temperature sensor that detects the substrate temperature of the drive circuit, etc. is provided, if the outside air temperature changes during the drive stop period, the detected temperature of the temperature sensor will be affected, so that the temperature drop caused by energization can be accurately grasped. Can not be. As a result, there is a risk that the current limit judgment based on the estimated temperature may deviate from the actual state at the time of restart after the drive is stopped. Then, even though the current limit is unnecessary, the motor output performance will be degraded due to excessive current limit, or the appropriate limit value will not be set when the current limit should be set, resulting in insufficient overheat protection. Will be invited.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a motor control device that appropriately executes current limitation during restart while suppressing dark current during a drive stop period. It is in.

  A motor control device according to one aspect of the present invention includes a drive circuit (60) that drives a motor (80), a substrate (20) on which the drive circuit is mounted, a substrate temperature sensor (71), and a substrate temperature acquisition unit ( 31), the substrate temperature storage unit (32), the outside air temperature acquisition unit (33), the outside air temperature storage unit (34), the rising temperature estimation unit (37), the rising temperature storage unit (38), and the current A limit value calculation unit (51) and an initial rise temperature correction unit (401, 403) are provided.

The substrate temperature sensor detects the temperature (Ts) of the substrate.
The substrate temperature acquisition unit acquires the substrate temperature detected by the substrate temperature sensor.
The substrate temperature storage unit stores an arbitrary reference time substrate temperature acquired by the substrate temperature acquisition unit as a substrate temperature storage value (Ts_m).
The outside air temperature acquisition unit acquires the outside air temperature (Tg) detected by the outside air temperature sensor.
The outside air temperature storage unit stores the outside air temperature at the reference time acquired by the outside air temperature acquisition unit as an outside air temperature storage value (Tg_m).

The rising temperature estimation unit estimates the rising temperature (Ti) of the element of the motor or drive circuit based on the value of the current flowing in the motor or drive circuit.
The rising temperature storage unit stores the rising temperature estimated by the rising temperature estimation unit as a rising temperature storage value (Ti_m).
Note that the substrate temperature storage unit, the outside air temperature storage unit, and the rising temperature storage unit are typically configured by a nonvolatile memory, and can retain the memory even when the control power supply is stopped.

The current limit value calculation unit calculates a current limit value based on the temperature rise estimated by the temperature rise estimation unit so as to limit the current supplied to the motor as the temperature rise is larger.
The first rise temperature correction unit is for correction calculated based on the substrate temperature memory value, the substrate temperature current value, the outside air temperature memory value, and the outside air temperature current value in the initial control at the time of restart after the drive of the motor is stopped by the drive circuit. The rising temperature memory value is corrected using the argument, and the initial rising temperature correction value (Ti_comp) is calculated.
The first rise temperature correction unit calculates the first rise temperature correction value as the degree of decrease from the substrate temperature storage value to the substrate temperature current value is relatively large with respect to the change from the outside air temperature storage value to the outside air temperature current value. Correct to make it smaller.

Here, the reference time at which the substrate temperature and the outside air temperature are stored is typically substantially equal to the temperature difference between the substrate temperature and the outside air temperature when the energization of the drive circuit is turned off and when the energization is off. “When driving is stopped” including a negligible time range.
As the correction argument, for example, a corrected substrate temperature difference (ΔTs_comp) or a corrected substrate temperature ratio (αs_comp) is used. The corrected substrate temperature difference includes a substrate temperature difference (ΔTs) that is a difference between the substrate temperature storage value and the substrate temperature current value, and an outside air temperature difference (ΔTg) that is a difference between the outside air temperature storage value and the outside air temperature current value. Is calculated based on The corrected substrate temperature ratio includes a substrate temperature ratio (αs) that is a ratio between the substrate temperature storage value and the substrate temperature current value, and an outside air temperature ratio (αg) that is a ratio between the outside air temperature storage value and the outside air temperature value. Is calculated based on

According to the present invention, since it is not necessary to hold a control power source for temperature estimation during the drive stop period, dark current can be suppressed as compared with the prior art of Patent Document 1.
The first rise temperature correction unit corrects the rise temperature stored value based on the information on the outside air temperature in addition to the substrate temperature in the first control at the time of restart after the drive is stopped, and calculates the first rise temperature correction value. Thereby, the current limitation at the time of restart can be appropriately executed while taking into consideration the influence due to the change in the outside air temperature.

The motor control device according to another aspect of the present invention does not include the substrate temperature storage unit and the outside air temperature storage unit as compared with the motor control device according to the above aspect. The initial temperature increase correction unit (405) is configured to increase the temperature based on the internal / external temperature value (Tdif) obtained by subtracting the current outside air temperature from the current substrate temperature in the initial control at the time of restart after the drive of the motor is stopped by the drive circuit. The stored value is corrected and the first rise temperature correction value (Ti_comp) is calculated. Then, the first rise temperature correction unit corrects the first rise temperature correction value to be smaller as the inside / outside temperature difference is smaller.
Also in this aspect, by correcting the stored temperature rise based on the information of the outside air temperature at the time of restart, appropriately limiting the current at the time of restart while suppressing the dark current during the drive stop period. Can do.

The whole block diagram of the motor control apparatus of 1st-4th embodiment. The example of the current limiting map by each embodiment. The block diagram of the first rise temperature correction | amendment part of 1st, 2nd embodiment. The example of the temperature increase correction factor map by 1st (solid line) and 2nd (broken line) embodiment. The flowchart of the memory | storage process at the time of a drive stop by each embodiment. The time chart explaining the timing of the temperature memory at the time of a drive stop. The flowchart of the initial process at the time of restart by 1st Embodiment. The time chart (1) which shows the operation example of 1st Embodiment. The time chart (2) which shows the operation example of 1st Embodiment. The time chart (3) which shows the operation example of 1st Embodiment. The flowchart of the initial process at the time of restart by 2nd Embodiment. The block diagram of the first rise temperature correction | amendment part of 3rd, 4th embodiment. The example of the temperature increase correction factor map by 3rd (solid line) and 4th (dashed line) embodiment. The flowchart of the initial process at the time of restart by 3rd Embodiment. The flowchart of the initial process at the time of restart by 4th Embodiment. The whole block diagram of the motor control apparatus of 5th, 6th embodiment. The block diagram of the first rise temperature correction | amendment part of 5th, 6th embodiment. The example of the raise temperature correction factor map by 5th (solid line) and 6th (dashed line) embodiment. The flowchart of the initial process at the time of restart by 5th Embodiment. The time chart which shows the operation example of 5th Embodiment. The flowchart of the initial process at the time of restart by 6th Embodiment.

Hereinafter, a plurality of embodiments of a motor control device will be described based on the drawings. In a plurality of embodiments, substantially the same configuration in the configuration diagram or substantially the same step in the flowchart is denoted by the same reference numeral or step number, and description thereof is omitted. The following first to sixth embodiments are collectively referred to as “this embodiment”.
The motor control device of this embodiment is used as a control device for a steering assist motor, for example, in an electric power steering device for a vehicle. In particular, the present embodiment will be described as being mounted on an engine vehicle equipped with an ignition switch.

Hereinafter, ON / OFF of the ignition switch is referred to as “IG-ON / OFF”. From the standpoint of the motor control device, IG-ON means that an external power power supply command is input, and IG-OFF means that the power power supply command is stopped. When power is supplied, the motor can be driven.
In the case of a control device mounted on a hybrid vehicle or an electric vehicle, “IG-ON / OFF” may be read as “ready ON / OFF”.

(First embodiment)
The motor control apparatus of 1st Embodiment is demonstrated with reference to FIGS.
FIG. 1 is an overall configuration diagram common to the first to fourth embodiments.
The motor control device 101 includes a substrate 20, a power relay 21 mounted on the substrate 20, a control circuit 30, and a drive circuit 60. The motor control device 101 converts DC power input from the battery 15 and outputs it to the motor 80.

  The electric power of the battery 15 is input to the motor control device 101 as a power PIG power source and a control IG power source. The PIG power is supplied to the drive circuit 60 via the power relay 21. The drive circuit 60 is a circuit including a so-called pre-driver and an inverter, and drives the motor 80. The drive circuit 60 includes switching elements such as MOSFETs, and elements such as comparators, resistors, and capacitors. The motor 80 is, for example, a three-phase brushless motor.

  The control circuit 30 is typically composed of a microcomputer, and generates a command signal to the drive circuit 60 by feedback control of the motor current Im according to the steering torque. In FIG. 1, illustration of a current sensor and a rotation angle sensor constituting general current feedback control and vector control is omitted. The motor current Im means a current flowing through the motor 80 or the drive circuit 60. In FIG. 1, the motor current Im is illustrated as being input from the motor 80, but the output current of the drive circuit 60 may be detected and fed back to the control circuit 30.

The control circuit 30 of the present embodiment estimates the rising temperature Ti of the elements of the drive circuit 60 based on the motor current Im, and further, based on the estimated temperature of each element estimated from the substrate temperature Ts and the rising temperature Ti, the motor 80. By limiting the current applied to the element, the element is protected from overheating.
In addition, the control circuit 30 of the present embodiment acquires the temperature Ts of the substrate 20 detected by the substrate temperature sensor 71 and the outside air temperature Tg detected by the outside air temperature sensor 73. The substrate temperature sensor 71 is a thermistor mounted on the substrate 20, for example. The outside air temperature sensor 73 may be anything, and may be used for other purposes of the vehicle.

The control circuit 30 includes a substrate temperature acquisition unit 31, a substrate temperature storage unit 32, an outside air temperature acquisition unit 33, an outside air temperature storage unit 34, a rise temperature estimation unit 37, a rise temperature storage unit 38, an initial rise temperature correction unit 401, and a current limit. A value calculation unit 51 and a current feedback (“FB” in the figure) calculation unit 52 are included.
The substrate temperature acquisition unit 31 acquires the substrate temperature Ts detected by the substrate temperature sensor 71.
The substrate temperature storage unit 32 stores an arbitrary reference substrate temperature Ts acquired by the substrate temperature acquisition unit 31 as a substrate temperature storage value Ts_m.

The outside air temperature acquisition unit 33 acquires the outside air temperature Tg detected by the outside air temperature sensor 73.
The outside air temperature storage unit 34 stores the outside air temperature Tg at the reference time acquired by the outside air temperature acquisition unit 33 as the outside air temperature storage value Tg_m.
That is, the substrate temperature storage unit 32 and the outside air temperature storage unit 34 store the same reference substrate temperature Ts and outside air temperature Tg. In the present embodiment, as a reference time, it is assumed that the drive circuit 60 is de-energized and includes a time range before and after the drive circuit 60 is turned off.

The rising temperature estimation unit 37 estimates the rising temperature Ti of the elements of the drive circuit 60 based on the integrated value of the motor current Im during normal operation. The estimation of the rising temperature Ti is based on the Joule heat equation (1). Here, Q represents Joule heat [J], R represents resistance [Ω], Im represents current [A], and t represents time [s].
Q = R × Im ² × t (1)
During the normal operation, the rising temperature Ti estimated by the rising temperature estimation unit 37 is notified to the current limit value calculation unit 51.

The rising temperature storage unit 38 stores the rising temperature Ti estimated by the rising temperature estimation unit 37 as a rising temperature storage value Ti_m.
The substrate temperature storage unit 32, the outside air temperature storage unit 34, and the elevated temperature storage unit 38 are typically configured by a non-volatile memory, and can retain the memory even when the control power supply is stopped.

The first rise temperature correction unit 401 calculates the first rise temperature correction value Ti_comp instead of the rise temperature Ti during normal operation in the initial control at the time of restart after the drive of the motor 80 is stopped by the drive circuit 60.
Hereinafter, the substrate temperature Ts and the outside air temperature Tg detected by the initial control at the time of restart are referred to as “current values”. The symbol Ts is used for both the substrate temperature Ts that changes with time and the current substrate temperature value Ts depending on the context. Similarly, the symbol Tg is used for both the outside air temperature Tg that changes with time and the outside air temperature current value Tg depending on the context.

The first rise temperature correction unit 401 corrects the rise temperature storage value Ti_m based on the substrate temperature storage value Ts_m, the substrate temperature current value Ts, the outside air temperature storage value Tg_m, and the outside air temperature current value Tg, and sets the first rise temperature correction value Ti_comp. Calculate. Details of the calculation process will be described later.
The first rise temperature correction value Ti_comp calculated by the first rise temperature correction unit 401 is notified to the current limit value calculation unit 51 via the rise temperature estimation unit 37.

The current limit value calculation unit 51 calculates the estimated temperature Tx_est of each element by adding the rising temperature Ti to the substrate temperature Ts according to Equation (2.1) at any time during normal operation.
Tx_est = Ts + Ti (2.1)
Further, the current limit value calculation unit 51 adds the initial temperature rise correction value Ti_comp to the substrate temperature current value Ts according to the equation (2.2) only for the initial control at the time of restart after the drive is stopped, and estimates each element. A temperature Tx_est is calculated.
Tx_est = Ts + Ti_comp (2.2)
Then, the current limit value calculation unit 51 calculates the current limit value Ilim with reference to, for example, a current limit map that defines the relationship between the element estimated temperature Tx_est and the current limit value Ilim.

According to the current limit map illustrated in FIG. 2, when the element estimated temperature Tx_est is lower than the critical temperature Txc, the current limit value Ilim is set equal to the maximum current value Imax determined by the rating of the elements of the drive circuit 60. That is, the current is not substantially limited. When the element estimated temperature Tx_est is equal to or higher than the critical temperature Txc, the current limit value Ilim is set lower as the element estimated temperature T_est is higher.
As described above, the current limit value calculation unit 51 calculates the current limit value Ilim so as to limit the current that flows to the motor 80 as the rising temperature Ti increases under the same substrate temperature current value Ts. Overheat protection.

The current feedback calculation unit 52 generates a command signal to the drive circuit 60 by feedback control of the motor current Im according to the steering torque. By operating the drive circuit 60 based on the command signal, the motor 80 originally outputs a desired assist torque.
Here, the current that can be supplied to the motor 80 is limited by the current limit value Ilim calculated by the current limit value calculation unit 51. If the current limit value Ilim is set lower than the required current value, the motor 80 cannot output a desired assist torque, and the assist performance is degraded.

Next, the configuration of the first rise temperature correction unit 401 of the first embodiment will be described with reference to FIG.
In the first embodiment and the next second embodiment, the corrected substrate temperature difference ΔTs_comp is used as a correction argument in the correction calculation of the first rise temperature.
The first temperature rise correction unit 401 includes subtractors 411 and 413, a correction coefficient multiplier 42, a subtractor 43, a correction rate map 481, and a correction rate multiplier 49.

  The subtractor 411 calculates the substrate temperature difference ΔTs by subtracting the substrate temperature storage value Ts_m from the substrate temperature current value Ts. The subtractor 413 calculates the outside air temperature difference ΔTg by subtracting the outside air temperature memory value Tg_m from the outside air temperature current value Tg. The correction coefficient multiplier 42 multiplies the outside air temperature difference ΔTg by a positive correction coefficient k. Here, the correction coefficient k indicates the magnitude of the influence of the change in the outside air temperature Tg on the change in the substrate temperature Ts, and is obtained by experiments and simulations according to the heat transfer characteristics of the peripheral components of the substrate. “K = 0.5 to 1.0”.

Further, the subtractor 43 subtracts a value obtained by multiplying the outside air temperature difference ΔTg by the correction coefficient k from the substrate temperature difference ΔTs to calculate a corrected substrate temperature difference ΔTs_comp as a correction argument.
That is, the first rise temperature correction unit 401 performs the calculations of equations (3.1) to (3.3).
ΔTs = Ts−Ts_m (3.1)
ΔTg = Tg−Tg_m (3.2)
ΔTs_comp = ΔTs−kΔTg (3.3)

The correction rate map 481 defines the relationship between the corrected substrate temperature difference ΔTs_comp and the rising temperature correction rate p. In the correction factor map 481 of the first embodiment shown by the solid line in FIG. 4, the correction factor p is 1 in the region where the post-correction substrate temperature difference Δs_comp is not less than the basic value B _ΔT . In the region where the corrected substrate temperature difference ΔTs_comp is less than the basic value B _ΔT , the correction rate p decreases as the negative corrected substrate temperature difference ΔTs_comp decreases, and gradually approaches zero.

In the example of the correction factor map 481 in FIG. 4, the basic value B _ΔT is set to a value slightly smaller than zero. Theoretically, if the post-correction substrate temperature difference ΔTs_comp is negative, it is considered that the correction rate p may be made smaller than 1 and the current limitation may be relaxed. However, in consideration of a margin due to a temperature detection error or the like, the basic value B _ΔT is set to a value smaller than 0, and when the corrected substrate temperature difference ΔTs_comp is less than the basic value B _ΔT , the current limit is relaxed. .
Since the base value B _ΔT is less than 0, the correction rate p is constant at 1 when the corrected substrate temperature difference ΔTs_comp is 0 or positive. Accordingly, when the corrected substrate temperature difference ΔTs_comp is positive, the corrected substrate temperature difference ΔTs_comp may be treated as zero. In that case, the region indicated by the two-dot chain line in the correction rate map 481 is omitted, and the upper limit of the corrected substrate temperature difference ΔTs_comp becomes zero.

The correction rate multiplier 49 multiplies the rising temperature storage value Ti_m by the rising temperature correction rate p obtained from the correction rate map 481 according to the equation (4) to calculate the first rising temperature correction value Ti_comp.
Ti_comp = Ti_m × p (4)
The first temperature increase correction value Ti_comp calculated in this way is notified to the current limit value calculation unit 51 via the temperature increase estimation unit 37 as described above.

Incidentally, as a conventional technique for estimating the motor temperature during the drive stop period, for example, there is one disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2002-363393).
The control device for the electric power steering device disclosed in Patent Document 1 does not turn on the power supply as long as the estimated temperature of the motor does not fall below a predetermined value even when the ignition switch is turned off and a power stop signal is input. Hold and continue to estimate motor temperature.
Further, the motor control device disclosed in Japanese Patent No. 2892899 calculates a shut-off time until the self-held power source is shut off based on the rising temperature of the motor after the power supply to the motor is shut off. Then, the motor control device outputs a power shut-off command after the calculated shut-off time has elapsed, and shuts off the self-held power source.

However, these conventional techniques have a problem that the dark current during driving stoppage increases because the control power supply for temperature estimation is held (that is, power latch) for a predetermined period after the driving power supply is stopped. . Therefore, the motor control device 101 of the present embodiment aims to suppress dark current without holding the control power supply after the drive is stopped.
FIG. 5 shows a flowchart of the storage process at the time of stopping driving common to the respective embodiments. In the following description of the flowchart, the symbol S represents “step”.

Here, first, the meanings of the terms “when driving is stopped” and “driving stop period” are defined.
“When driving is stopped” is based on the time when energization of the drive circuit 60 is turned off, and is relatively short including a time range in which the temperature difference between the substrate temperature Ts and the outside air temperature Tg when the energization is turned off is substantially negligible. It means a period (for example, a period within 1 second). In the present embodiment, the time when the drive is stopped is a reference time when the substrate temperature Ts and the outside air temperature Tg are stored in the substrate temperature storage unit 32 and the outside air temperature storage unit 34.
The “drive stop period” means a relatively long period from the drive stop time tq to the restarting Trs, for example, from several minutes to several hours or more.

In S01, during the normal operation in which the IG is in the ON state, the rising temperature estimation unit 37 estimates the rising temperature Ti of the element of the drive circuit 60 based on the value of the motor current Im.
In S02, it is determined whether IG-OFF, that is, whether the driving is stopped. If NO in S02, the process in S01 is repeated. If YES in S02, each temperature is stored in the storage units 32, 34, and 38 in S03.

Specifically, the substrate temperature Ts acquired by the substrate temperature acquisition unit 31 when the drive is stopped is stored in the substrate temperature storage unit 32 as the substrate temperature storage value Ts_m, and the outside temperature Tg acquired by the outside temperature acquisition unit 33 when the drive is stopped is outside. It is stored in the outside air temperature storage unit 34 as the air temperature memory value Tg_m. Further, the rise temperature Ti estimated by the rise temperature estimation unit 37 immediately before the drive is stopped is stored in the rise temperature storage unit 38 as the rise temperature storage value Ti_m.
After each temperature is stored in S03, the control power supply is turned off in S04.

The detailed timing of temperature storage when driving is stopped will be described with reference to FIG. The timing at which each temperature is stored need not exactly coincide with the IG-OFF moment.
For example, as shown in FIG. 6A, in the time range in which the temperature difference between the substrate temperature Ts and the outside air temperature Tg when the power is off is substantially negligible, the substrate temperature is delayed by a minute time δ from the stop time tq. Ts and the outside air temperature Tg may be stored. The stored value stored in this way is read at restart trs.

  Further, the driving of the motor 80 is stopped not only when the IG-OFF is performed as intended by the driver but also when the battery 15 is unexpectedly removed. In order to retain the stored value even in the case of such an unexpected drive stop, as shown in FIG. 6B, each temperature may be stored and updated at a predetermined cycle τ during normal operation. Then, each temperature stored and updated at the end before the drive is stopped is read in at the time of restarting trs. After restarting, each temperature is stored and updated again at a predetermined cycle τ.

FIG. 7 shows a flowchart of the initial process at the time of restart according to the first embodiment.
In S11, the IG is turned on after the drive is stopped. Using this as a trigger, the initial processing at the time of restart is executed.

In step S <b> 12, the first rise temperature correction unit 401 acquires the current value of the substrate temperature Ts from the substrate temperature acquisition unit 31, and acquires the current value of the outside air temperature Tg from the outside air temperature acquisition unit 33. Further, the first rise temperature correction unit 401 reads the substrate temperature storage value Ts_m from the substrate temperature storage unit 32, reads the outside air temperature storage value Tg_m from the outside air temperature storage unit 34, and further reads the rise temperature storage value Ti_m from the rise temperature storage unit 38. Read.
Subsequently, in S13, the first temperature rise correction unit 401 calculates the substrate temperature difference ΔTs by subtracting the substrate temperature storage value Ts_m from the substrate temperature current value Ts, and subtracts the outside air temperature storage value Tg_m from the outside air temperature current value Tg. The temperature difference ΔTg is calculated. In step S14, the initial temperature rise correction unit 401 calculates the corrected substrate temperature difference ΔTs_comp using the equation (3.3).

Next, the first rise temperature correction unit 401 calculates the rise temperature correction rate p with reference to the correction rate map 481 in S15, and multiplies the rise temperature storage value Ti_m by the correction rate p in S16 to obtain the first rise temperature correction value. Calculate Ti_comp. The first temperature rise correction value Ti_comp is notified to the current limit value calculation unit 51 via the temperature rise estimation unit 37.
In S18, the current limit value calculating unit 51 adds the initial temperature rise correction value Ti_comp to the substrate temperature current value Ts to calculate the estimated temperature Tx_est of each element. In S19, the current limit value calculation unit 51 refers to the current limit map of FIG. 2 and calculates the current limit value Ilim based on the estimated temperature Tx_est of each element.

Next, an operation example of the first embodiment will be described with reference to the time charts of FIGS. Each figure shows changes in the substrate temperature Ts and the outside air temperature Tg from the stop time tq of the motor drive when the IG has shifted from the ON state to the OFF state, and the restart time trs from the restart time trs when the IG is turned ON again. The rising temperature correction factor p and the current limit value Ilim set in the initial control are shown.
During normal operation before the stop time tq, the substrate temperature Ts rises due to heat generation of the element due to energization of the drive circuit 60, and the rise temperature Ti is calculated based on the motor current Im as needed. At this time, the rising temperature correction rate p corresponds to 1, and the current limit value Ilim is set lower than the maximum current value Imax determined by the rating of the elements of the drive circuit 60 and the like.

When IG is turned OFF, the substrate temperature Ts and the outside air temperature Tg at the stop time tq are stored as the substrate temperature memory value Ts_m and the outside air temperature memory value Tg_m. In any of FIGS. 8 to 10, the substrate temperature storage value Ts_m is higher than the outside air temperature storage value Tg_m.
After the stop time tq, the substrate temperature Ts basically decreases because no heat is generated by energization. On the other hand, there are various patterns of changes in the outside air temperature Tg. FIG. 8 shows a pattern in which the outside air temperature Tg does not change, FIG. 9 shows a pattern in which the outside air temperature Tg increases, and FIG. 10 shows a pattern in which the outside air temperature Tg decreases.

  As a comparative example for comparison with the control according to the first embodiment, a control configuration in which the substrate temperature difference ΔTs is not corrected by the outside air temperature difference ΔTg is assumed. This comparative example may be considered as a case where the correction coefficient k in Equation (3.3) is zero. In the comparative example, the rising temperature correction rate p is calculated based only on the substrate temperature difference ΔTs using the same correction rate map 481 as in the first embodiment.

In the pattern of FIG. 8, the substrate temperature Ts drops to the same level as the outside air temperature Tg at the time of restarting trs. In an actual situation, this corresponds to a case where the drive stop period is sufficiently long, and it is considered that the estimated value of the rise temperature Ti estimated before the stop time tq may be cleared to zero.
In FIG. 8, the substrate temperature difference ΔTs is a negative value, and the outside air temperature difference ΔTg is almost zero. Therefore, the corrected substrate temperature difference ΔTs_comp is substantially equal to the substrate temperature difference ΔTs and takes a negative value.

  When the absolute value of the negative substrate temperature difference ΔTs is relatively large, the rising temperature correction rate p is 0 from the correction rate map 481. Further, if the substrate temperature Ts itself at the time of restarting trs is relatively low, it is determined that almost no current limitation is necessary. As a result, the current limit value Ilim in the initial control at the time of restarting trs is set to be as high as the maximum current value Imax.

Thereby, for example, excessive current limitation can be suppressed as compared with the case where the elevated temperature stored value Ti_m at the time of stop tq is used as it is for the initial control of trs at the time of restart.
However, in the pattern of FIG. 8, since the outside air temperature difference ΔTg during driving stop is substantially 0, no substantial difference occurs between the first embodiment and the comparative example. That is, in the pattern of FIG. 8, the current limitation can be suppressed even in the comparative example, and the superiority of the first embodiment does not clearly appear.

Subsequently, in the pattern of FIG. 9, the outside air temperature Tg rises while driving is stopped. The substrate temperature Ts decreases until it matches the outside air temperature Tg, and then rises as the outside air temperature Tg increases.
In an actual situation, for example, in an area where the temperature difference between day and night is high, such as in the desert or inland, the day after driving in a very low temperature environment (eg -10 ° C) the night before, IG-ON in a high temperature environment (eg 40 ° C) think of. In this case, the outside air temperature difference ΔTg is + 50 ° C. On the other hand, if the substrate temperature Ts is 30 ° C. at the stop tq and 40 ° C. at the restart trs, the substrate temperature difference ΔTs is + 10 ° C. That is, the drive stop period is sufficiently long, and the heat generation of the element due to energization during the previous night operation is completely eliminated, and the estimated value of the rise temperature Ti may be cleared to zero, but the substrate temperature Ts There is a situation where it rises.

  In FIG. 9 assuming such a situation, the substrate temperature Ts at the time of restarting trs becomes higher than the substrate temperature storage value Ts_m, and the substrate temperature difference ΔTs becomes a positive value. The outside air temperature difference ΔTg is a positive value having a larger absolute value than the substrate temperature difference ΔTs, and “−kΔTg” is a negative value. Depending on the value of the correction coefficient k, assuming that the absolute value of “−kΔTg” is larger than the substrate temperature difference ΔT, the corrected substrate temperature difference ΔTs_comp is a negative value. That is, the sign of the corrected substrate temperature difference ΔTs_comp is inverted with respect to the uncorrected substrate temperature difference ΔTs.

  Therefore, from the correction factor map 481, the rising temperature correction factor p is a value smaller than 1 and close to zero. However, since the substrate temperature Ts itself at the time of restarting trs is relatively high, it is determined that a certain amount of current limitation is necessary. As a result, the current limit value Ilim in the initial control at the time of restarting trs is higher than the value immediately before the stop time tq and slightly lower than the maximum current value Imax.

  On the other hand, in the comparative example indicated by the triangle mark, the rising temperature correction rate p is 1 based on the positive substrate temperature difference ΔTs before correction, and the current limitation is maintained. Therefore, although the substrate temperature Ts is only increased with the increase in the outside air temperature Tg, excessive current limitation is performed, so that the motor output performance is not sufficiently exhibited. For example, in an electric power steering device, the assist performance is reduced.

In the pattern of FIG. 10, the outside air temperature Tg decreases while driving is stopped. In addition, the degree of decrease is greater than the degree of decrease in the substrate temperature Ts. In other words, the substrate temperature Ts is not lowered as much as the outside air temperature Tg, and it is considered that the heat dissipation performance is inferior. Therefore, although the substrate temperature Ts is lowered, it is a situation that requires attention from the viewpoint of protection.
At this time, the substrate temperature difference ΔTs is a negative value. The outside air temperature difference ΔTg is a negative value having a larger absolute value than the substrate temperature difference ΔTs, and “−kΔTg” is a positive value. Depending on the value of the correction coefficient k, assuming that the absolute value of “−kΔTg” is larger than the absolute value of the substrate temperature difference ΔTs, the corrected substrate temperature difference ΔTs_comp becomes a positive value. That is, the sign of the corrected substrate temperature difference ΔTs_comp is inverted with respect to the uncorrected substrate temperature difference ΔTs.

Therefore, from the correction rate map 481, the temperature increase correction rate p is 1 as indicated by the square marks. As a result, the current limit value Ilim in the initial control at the time of restarting trs is maintained at the value immediately before the stop time tq. That is, although the substrate temperature Ts is lowered, the current limit value Ilim is determined based on a concept that gives priority to overheating protection of the element from the comparison with the degree of decrease in the outside air temperature Tg.
On the other hand, in the comparative example indicated by the triangle mark, the temperature rise correction rate p becomes a value smaller than 1 based on the negative substrate temperature difference ΔTs before correction, and works to suppress the current limitation. Therefore, there is a possibility that an element on the substrate 20 having poor heat dissipation performance cannot be sufficiently protected.

(effect)
As described above, the motor control device 101 according to the first embodiment does not need to hold a control power source for temperature estimation during the drive stop period, and therefore suppresses dark current as compared with the conventional technique of Patent Document 1. be able to.
In addition, the initial temperature rise correction unit 401 corrects the temperature rise value Ti_m based on the information on the outside air temperature Tg in addition to the substrate temperature Ts in the initial control at the time of restart after the drive is stopped, and the initial temperature rise correction value Ti_comp. Is calculated. Thereby, the current limitation at the time of restart can be appropriately executed while considering the influence of the change in the outside air temperature Tg.

Specifically, when the degree of decrease from the substrate temperature storage value Ts_m to the substrate temperature current value Ts is relatively large with respect to the change from the outside air temperature storage value Tg_m to the outside air temperature current value Tg, the initial rise temperature correction value Ti_comp Correct to reduce. In the first embodiment, a smaller negative post-correction substrate temperature difference ΔTs_comp corresponds to “the degree of decrease from the substrate temperature storage value Ts_m to the substrate temperature current value Ts is relatively large”.
More specifically, as shown in the patterns of FIGS. 9 and 10, the substrate temperature difference ΔTs is corrected by the outside air temperature difference ΔTg and the corrected substrate temperature difference ΔTs_comp is calculated, whereby the substrate temperature Ts with respect to the change in the outside air temperature Tg. It is possible to evaluate the degree of relative decrease in.

  Thereby, it is possible to more appropriately determine the necessity of current limitation in the initial control at the time of restarting trs. In the pattern of FIG. 9, excessive current limitation is avoided and the motor output performance is effectively exhibited. For example, in the drive control of the assist motor of the electric power steering device, good assist performance can be ensured. On the other hand, in the pattern of FIG. 10, since the degree of decrease in the substrate temperature with respect to the change in the outside air temperature Tg is relatively small, current limiting is performed to protect the element from overheating. Therefore, it is possible to suitably achieve both overheating protection of the element and ensuring of the motor output performance.

  For example, a steering assist motor of an electric power steering apparatus has a need to output a large torque abruptly as compared with a motor for steady rotation. Further, the place where the motor control device 101 is installed is generally an environment that is severely limited in space and disadvantageous for heat dissipation. In addition, since high reliability is required, it is particularly important to properly prevent the failure of the element and ensure the output of the motor 80 as much as possible. Therefore, the motor control device 101 according to the present embodiment effectively exhibits the effect of suitably achieving both overheating protection of the element and ensuring of the motor output performance.

(Second Embodiment)
The second embodiment is different from the first embodiment in the method of calculating the rising temperature correction rate p by the first rising temperature correction unit. In the first embodiment, the correction rate p is calculated with reference to the correction rate map 481 that continuously changes according to the corrected substrate temperature difference ΔTs_comp that is a correction argument. On the other hand, in the second embodiment, a correction rate p defined by two values is selected by comparing the corrected substrate temperature difference ΔTs_comp with a temperature difference critical value C _ΔT which is a value equal to or less than zero.
Note that the map does not necessarily need to be used in the binary selection calculation, but for convenience of comparison with the first embodiment, a binary map is indicated by a broken line in FIG. The same applies to fourth and sixth embodiments described later.

In this binary map, when the corrected substrate temperature difference ΔTs_comp is less than the temperature difference critical value C _ΔT , the correction rate p is 0, and when the corrected substrate temperature difference ΔTs_comp is greater than or equal to the temperature difference critical value C _ΔT , the correction rate p is 1.
By multiplying the temperature rise value Ti_m by the correction factor p, the initial temperature rise correction value Ti_comp is set to 0 when the corrected substrate temperature difference ΔTs_comp is less than the temperature difference critical value C _ΔT . When the post-correction substrate temperature difference ΔTs_comp is equal to or greater than the temperature difference critical value C _ΔT , the initial temperature increase correction value Ti_comp is set equal to the temperature increase stored value Ti_m.

As shown in the flowchart of FIG. 11, the initial process at the time of restart according to the second embodiment includes steps S25 to S27 instead of S15 and S16 of FIG. 7.
When the corrected substrate temperature difference ΔTs_comp is less than the temperature difference critical value C _ΔT , YES is determined in S25, and the initial rise temperature correction value Ti_comp is set to 0 in S26.
When the post-correction substrate temperature difference ΔTs_comp is equal to or greater than the temperature difference critical value C _ΔT , NO is determined in S25, and the initial rising temperature correction value Ti_comp is set equal to the rising temperature storage value Ti_m in S27.
The second embodiment basically has the same effects as those of the first embodiment, and the calculation of the rising temperature correction factor p is made binary selection, thereby simplifying the processing and reducing the calculation load. it can.

(Third and fourth embodiments)
Third and fourth embodiments will be described with reference to FIGS. The third and fourth embodiments use the post-correction substrate temperature ratio αs_comp as a correction argument in the first rising temperature correction calculation as compared to the first and second embodiments.
As shown in FIG. 12, the first rise temperature correction unit 403 includes a temperature conversion unit 44, dividers 451, 453, 46, a correction rate map 483, and a correction rate multiplier 49.

The temperature conversion unit 44 uniformly subtracts the reference temperature To from the current substrate temperature value Ts, the substrate temperature storage value Ts_m, the outside air temperature current value Tg, and the outside air temperature storage value Tg_m input to the first rise temperature correction unit 403. Convert the value. The reference temperature To is set to a predetermined processing target temperature range for the substrate temperature Ts and the outside air temperature Tg, that is, a temperature outside the temperature range from the minimum temperature to the maximum temperature that can be assumed. For example, when the processing target temperature range is −40 ° C. to 80 ° C., the reference temperature To can be set to a temperature such as −50 ° C. lower than the minimum temperature or 100 ° C. higher than the maximum temperature.
Hereinafter, a case where the reference temperature To is set to the low temperature side of the processing target temperature range, that is, a temperature lower than the minimum temperature will be described. Note that the case where the absolute temperature is used as the temperature unit corresponds to the case where the reference temperature To is set to 0K (that is, −273 ° C.).

Here, for example, the substrate temperature after conversion with respect to the substrate temperature Ts before conversion is expressed as [Ts]. Each temperature is represented by the formulas (5.1) to (5.4).
[Ts] = Ts−To (5.1)
[Ts_m] = Ts_m-To (5.2)
[Tg] = Tg−To (5.3)
[Tg_m] = Tg_m-To (5.4)
For example, the outside air temperature Tg in the cold season may be 0 ° C. or less, but all the temperatures after conversion are positive values. This prevents the occurrence of discontinuity due to zero division or sign inversion in division. That is, this temperature conversion process has significance as preparation for division.

The divider 451 divides the converted substrate temperature current value [Ts] by the substrate temperature storage value [Ts_m] to calculate the substrate temperature ratio αs. The divider 453 calculates the outside air temperature ratio αg by dividing the converted outside air temperature present value [Tg] by the outside air temperature memory value [Tg_m]. Furthermore, the divider 46 calculates the corrected substrate temperature ratio αs_comp by dividing the substrate temperature ratio αs by the outside air temperature ratio αg.
That is, the first rise temperature correction unit 403 performs calculations of equations (6.1) to (6.3).
αs = [Ts] / [Ts_m] (6.1)
αg = [Tg] / [Tg_m] (6.2)
αs_comp = αs / αg (6.3)

The correction rate map 483 defines the relationship between the corrected substrate temperature ratio αs_comp and the rising temperature correction rate p. In the correction factor map 483 of the third embodiment indicated by the solid line in FIG. 13, the correction factor p is 1 in the region where the post-correction substrate temperature ratio αs_comp is equal to or greater than the basic value B _α . Further, the corrected substrate temperature ratio αs_comp is in the region of less than basal values B _alpha, as the correction factor p is the corrected substrate temperature ratio αs_comp smaller decreases asymptotically to zero.

In the example of the correction factor map 483 in FIG. 13, the basic value _Bα is set to a value slightly smaller than 1. The reason is the same as the reason why the basic value B _ΔT in the correction factor map 481 of the first embodiment is set to a value smaller than 0. For basal values B _alpha is less than 1, the correction factor p is 1 or more regions corrected substrate temperature ratio αs_comp becomes constant at 1. Accordingly, when the corrected substrate temperature ratio αs_comp is larger than 1, the corrected substrate temperature ratio αs_comp may be handled as 1. In this case, the region indicated by the two-dot chain line in the correction rate map 483 is omitted, and the upper limit of the corrected substrate temperature ratio αs_comp is 1.

FIG. 14 shows a flowchart of the initial process at the time of restart according to the third embodiment.
The first rise temperature correction unit 403 converts the substrate temperature current value Ts, the substrate temperature storage value Ts_m, the outside air temperature current value Tg, and the outside air temperature storage value Tg_m in S33 after S12, and then converts the substrate temperature ratio αs and the outside air temperature ratio. αg is calculated, and the corrected substrate temperature ratio αs_comp is calculated in S34.
In step S35, the initial temperature rise correction unit 403 calculates the temperature rise correction rate p with reference to the correction rate map 483 based on the corrected substrate temperature ratio αs_comp.
Subsequent S16, S18, and S19 are the same as those in FIG.

  In the third embodiment, the post-correction substrate temperature ratio αs_comp is smaller than 1 and close to 0 indicates that “the substrate temperature stored value Ts_m is changed to the substrate temperature current value with respect to the change from the outside air temperature stored value Tg_m to the outside air temperature current value Tg. This corresponds to “the degree of decrease in Ts is relatively large”. Further, the smaller the substrate temperature ratio after correction αs_comp is, the smaller the initial temperature rise correction value Ti_comp is corrected, so that the same effects as the first embodiment can be obtained.

In the fourth embodiment, the calculation of the rising temperature correction rate p is a binary selection with respect to the third embodiment.
In the binary map of the fourth embodiment shown by the broken line in FIG. 13, when the corrected substrate temperature ratio αs_comp is less than the temperature ratio critical value C _α which is 1 or less, the correction rate p is 0, and the corrected substrate when the temperature ratio αs_comp is above the temperature ratio threshold value C _alpha, correction factor p is 1.
By correction factor p to increase the temperature stored value Ti_m are multiplied, the corrected substrate temperature ratio αs_comp the time below the temperature ratio threshold C _alpha, initial rise temperature correction value Ti_comp is set to 0. Further, the corrected substrate temperature ratio αs_comp is when the above temperature ratio threshold value C _alpha, initial rise temperature correction value Ti_comp is set equal to the rising temperature storage value Ti_m.

As shown in the flowchart of FIG. 15, the initial process at the time of restart according to the fourth embodiment includes steps S45 to S47 instead of S35 and S36 of FIG.
When the corrected substrate temperature ratio αs_comp is less than the temperature ratio threshold C _alpha, YES is determined in S45, the first elevated temperature correction value Ti_comp is set to 0 in S46.
When the corrected substrate temperature ratio αs_comp is above the temperature ratio threshold value C _alpha, NO is determined in S45, the first elevated temperature correction value Ti_comp is set equal to the rising temperature storage value Ti_m at S47.
The fourth embodiment basically has the same effects as those of the third embodiment, and the calculation of the rising temperature correction rate p is selected as a binary value, thereby simplifying the processing and reducing the calculation load. it can.

(Fifth and sixth embodiments)
Fifth and sixth embodiments will be described with reference to FIGS. In the fifth and sixth embodiments, the first rise temperature correction value Ti_comp is calculated using the inside / outside temperature difference Tdif.
As shown in FIG. 16, the motor control device 105 of the fifth embodiment does not include the substrate temperature storage unit 32 and the outside air temperature storage unit 34 compared to the motor control device 101 shown in FIG. 1. The first rise temperature correction unit 405 corrects the rise temperature storage value Ti_m based on only the current values of the substrate temperature Ts and the outside air temperature Tg in the initial control at the time of restart after the operation of the drive circuit 60 is stopped. The correction value Ti_comp is calculated.

As shown in FIG. 17, the subtractor 475 of the first rise temperature correction unit 405 calculates an internal / external temperature difference Tdif (= Ts−Tg) by subtracting the external air temperature current value Tg from the substrate temperature current value Ts. The correction rate map 485 defines the relationship between the internal / external temperature difference Tdif and the rising temperature correction rate p.
In the correction rate map 485 of the fifth embodiment shown by the solid line in FIG. 18, the correction rate p is 0 when the internal / external temperature difference Tdif is 0, and the correction rate p increases as the internal / external temperature difference Tdif increases from 0. Asymptotically.

FIG. 19 shows a flowchart of the initial process at the time of restart according to the fifth embodiment.
The first rise temperature correction unit 405 obtains the current values of the substrate temperature Ts and the outside air temperature Tg and reads the rise temperature storage value Ti_m from the rise temperature storage unit 38 in S52 after S11.
The first rise temperature correction unit 405 calculates the internal / external temperature difference Tdif (= Ts−Tg) in S54, and calculates the rise temperature correction rate p with reference to the correction rate map 485 in S55.
Subsequent S16, S18, and S19 are the same as those in FIG.

Next, an operation example of the fifth embodiment will be described with reference to a time chart of FIG.
When the drive is stopped, the substrate temperature Ts is higher than the outside air temperature Tg, and both the substrate temperature Ts and the outside air temperature Tg are lowered during the drive stop. At this time, since the amount of decrease in the substrate temperature Ts is larger than the amount of decrease in the external temperature Tg, the internal / external temperature difference Tdif gradually decreases, and the value at the time of restarting trs is close to zero. Therefore, the correction rate p is close to 0 from the correction rate map 485. As a result, it is determined that the current limit is almost unnecessary, and the current limit value Ilim in the initial control at the time of restart is set to a value close to the maximum current value Imax.

On the other hand, in the example of FIG. 20, when the internal / external temperature difference Tdif of the restarting trs is relatively large, the correction rate p becomes a value close to 1, and the initial rise temperature correction value Ti_comp becomes the rise temperature storage value Ti_m. A close value. As a result, the current limit value Ilim in the initial control at the time of restart is set to a value equivalent to that immediately before the stop time tq.
Also in the fifth embodiment, by correcting the elevated temperature memory value Ti_m based on the information of the outside air temperature Tg at the time of restart, the current limit at the time of restart is appropriately controlled while suppressing the dark current during the drive stop period. Can be executed. Moreover, the board | substrate temperature storage part 32 and the external temperature memory | storage part 34 can be made unnecessary with respect to the said 1st-4th embodiment.

In the sixth embodiment, the calculation of the rising temperature correction rate p is a binary selection with respect to the fifth embodiment.
In the binary map of the sixth embodiment shown by the broken line in FIG. 18, when the internal / external temperature difference Tdif is less than the internal / external temperature difference critical value Cdif, the correction rate p is 0, and the internal / external temperature difference Tdif is the internal / external temperature difference critical value Cdif. At the above time, the correction rate p is 1.
By multiplying the rise temperature memory value Ti_m by the correction factor p, the initial rise temperature correction value Ti_comp is set to 0 when the inside / outside temperature difference Tdif is less than the inside / outside temperature difference critical value Cdif. When the internal / external temperature difference Tdif is equal to or greater than the internal / external temperature difference critical value Cdif, the initial temperature increase correction value Ti_comp is set equal to the temperature increase stored value Ti_m.

As shown in the flowchart of FIG. 21, the initial process at the time of restart according to the sixth embodiment includes steps S65 to S67 instead of S55 and S16 of FIG.
When the internal / external temperature difference Tdif is less than the internal / external temperature difference critical value Cdif, YES is determined in S65, and the initial rise temperature correction value Ti_comp is set to 0 in S66.
When the internal / external temperature difference Tdif is equal to or greater than the internal / external temperature difference critical value Cdif, NO is determined in S65, and the initial temperature increase correction value Ti_comp is set equal to the temperature increase stored value Ti_m in S67.
The sixth embodiment basically has the same effect as that of the fifth embodiment, and the calculation of the rising temperature correction factor p is made binary selection, thereby simplifying the processing and reducing the calculation load. it can.

(Other embodiments)
(A) In the calculation of the first rise temperature correction unit 401 in the first and second embodiments, the calculation formulas for the substrate temperature difference ΔTs and the outside air temperature difference ΔTg are the above formulas (3.1) and (3.2). On the contrary, they may be defined as in equations (7.1) and (7.2).
ΔTs = Ts_m−Ts (7.1)
ΔTg = Tg_m−Tg (7.2)

In this case, the temperature increase correction rate map is represented by inverting the horizontal axis between positive and negative with respect to the map of FIG. 4 with the position of “ΔTs_comp = 0” being symmetric. As the positive post-correction substrate temperature difference ΔTs_comp is larger, the rising temperature correction rate p is decreased from 1 and gradually approaches 0. That is, the first temperature rise correction unit corrects the first temperature rise correction value Ti_comp to be smaller as the corrected substrate temperature difference ΔTs_comp is larger.
In the correction rate map, the lower limit of the corrected substrate temperature difference ΔTs_comp may be set to 0, and the region of “ΔTs_comp <0” where the correction rate p is constant at 1 may be omitted.

In the binary map corresponding to the second embodiment, when the corrected substrate temperature difference ΔTs_comp is larger than the temperature difference critical value C _{ΔT, the} correction rate p becomes 0, and the corrected substrate temperature difference ΔTs_comp is equal to or lower than the temperature difference critical value C _ΔT . Sometimes the correction factor p is 1.
Thus, a form in which the magnitude relationship is merely reversed by defining the positive and negative of the expression in reverse is interpreted as being included in the technical scope of the invention described in the claims.

(B) In the calculation of the first rise temperature correction unit 403 of the third and fourth embodiments, the calculation formulas for the substrate temperature ratio αs and the outside air temperature ratio αg are the above formulas (6.1) and (6.2). On the contrary, they may be defined as in equations (8.1) and (8.2).
αs = [Ts_m] / [Ts] (8.1)
αg = [Tg_m] / [Tg] (8.2)

In this case, the rising temperature correction factor map is represented by a reciprocal relationship on the horizontal axis with respect to the map of FIG. 13 with the position of “αs_comp = 1” as a reference. As the post-correction substrate temperature ratio αs_comp is larger than 1, the rising temperature correction rate p decreases from 1 and gradually approaches 0. That is, the first temperature rise correction unit corrects the first temperature rise correction value Ti_comp to be smaller as the post-correction substrate temperature ratio αs_comp is larger.
In the correction rate map, the lower limit of the post-correction substrate temperature ratio αs_comp may be set to 1, and the region of “αs_comp <1” where the correction rate p is constant at 1 may be omitted.

The binary map corresponding to the fourth embodiment, the corrected substrate temperature ratio αs_comp is next zero correction factor p when the temperature ratio is greater than a critical value C _alpha, corrected substrate temperature ratio αs_comp temperature ratio threshold C _alpha following Sometimes the correction factor p is 1.
As described above, a form in which the magnitude relationship is merely reversed by defining the denominator and the numerator in reverse is interpreted as being included in the technical scope of the invention described in the claims.
Note that the magnitude relationship of the calculated values is also reversed when the reference temperature To in the temperature conversion is set to the high temperature side of the processing target temperature range. This form is also interpreted as being included in the technical scope of the invention described in the claims.

  (C) The first rise temperature correction unit of the above embodiment calculates the first rise temperature correction value Ti_comp by multiplying the rise temperature storage value Ti_m by the rise temperature correction rate p obtained from the correction argument. In another embodiment, the corrected temperature p is not used, and the increased temperature stored value Ti_m is corrected by a plurality of maps that directly define the relationship between the correction argument and the initial increased temperature corrected value Ti_comp for each increased temperature stored value Ti_m. You may do it.

(D) The drive circuit of the motor control device and the motor to be driven are not limited to the inverter and the three-phase brushless motor exemplified in the above embodiment, but may be an H bridge circuit, a DC motor, or the like.
(E) The motor control device of the present invention is not limited to the steering assist motor of the electric power steering device, and may be applied as a device for driving any motor. In particular, it is effective as a control device for a vehicle-mounted motor or the like in which the change in the outside air temperature during the drive stop period is relatively large.
As mentioned above, this invention is not limited to such embodiment, In the range which does not deviate from the meaning of invention, it can implement with a various form.

101, 105 ... motor control device,
20 ... substrate,
31 ... Substrate temperature acquisition unit, 32 ... Substrate temperature storage unit,
33 ... Outside temperature acquisition unit, 34 ... Outside temperature storage unit,
37 ... rising temperature estimation unit, 38 ... rising temperature storage unit,
401, 403, 405 ... first rise temperature correction unit,
51 ... Current limit value calculation unit,
60 ... Drive circuit,
71 ... Substrate temperature sensor, 73 ... Outside air temperature sensor,
80: Motor.

Claims (12)

A drive circuit (60) for driving the motor (80);
A substrate (20) on which the drive circuit is mounted;
A substrate temperature sensor (71) for detecting the temperature (Ts) of the substrate;
A substrate temperature acquisition unit (31) for acquiring a substrate temperature detected by the substrate temperature sensor;
A substrate temperature storage unit (32) for storing an arbitrary reference substrate temperature acquired by the substrate temperature acquisition unit as a substrate temperature storage value (Ts_m);
An outside air temperature acquisition unit (33) for acquiring the outside air temperature (Tg) detected by the outside air temperature sensor (73);
An outside air temperature storage unit (34) for storing the outside air temperature at the reference time acquired by the outside air temperature acquisition unit as an outside air temperature memory value (Tg_m);
A temperature rise estimation unit (37) for estimating a temperature rise (Ti) of an element of the drive circuit based on a value of a current flowing through the motor or the drive circuit;
A rise temperature storage section (38) for storing the rise temperature estimated by the rise temperature estimation section as a rise temperature storage value (Ti_m);
A current limit value calculation unit (51) that calculates a current limit value so as to limit a current to be supplied to the motor as the temperature rises, based on the rise temperature estimated by the rise temperature estimation unit;
In the initial control at the time of restart after the drive of the motor is stopped by the drive circuit, the correction argument calculated based on the substrate temperature memory value, the substrate temperature current value, the outside air temperature memory value, and the outside air temperature current value is used. First temperature rise correction unit (401, 403) for correcting the rise temperature memory value and calculating the first temperature rise correction value (Ti_comp);
With
The first rise temperature correction unit corrects the first rise temperature correction as the degree of decrease from the substrate temperature storage value to the substrate temperature current value is relatively large with respect to the change from the outside temperature storage value to the outside air temperature current value. Motor control device that corrects the value to be smaller.   2. The reference time is when the drive circuit is turned off, and when the drive is stopped including a time range in which a temperature difference between the substrate temperature and the outside air temperature at the time of turning off the current is substantially negligible. The motor control device described in 1. The first rise temperature correction unit (401)
Based on the substrate temperature difference (ΔTs) that is the difference between the substrate temperature stored value and the substrate temperature current value, and the outside air temperature difference (ΔTg) that is the difference between the outside air temperature stored value and the outside air temperature current value, The motor control device according to claim 1 or 2, wherein a corrected substrate temperature difference (ΔTs_comp) that is a correction argument is calculated. A value obtained by subtracting the substrate temperature memory value from the substrate temperature current value is defined as the substrate temperature difference, and a value obtained by subtracting the outside air temperature memory value from the outside air temperature current value is defined as the outside air temperature difference.
The first rise temperature correction unit calculates the corrected substrate temperature difference by subtracting a value obtained by multiplying the outside air temperature difference by a positive correction coefficient (k) from the substrate temperature difference, and the corrected substrate temperature difference is small. The motor control device according to claim 3, wherein the correction is performed so that the initial temperature rise correction value is decreased.   5. The motor control device according to claim 4, wherein the first temperature rise correction unit treats the post-correction substrate temperature difference as 0 when the post-correction substrate temperature difference is positive. The initial temperature rise correction unit is
When the substrate temperature difference after correction is less than the temperature difference critical value (C _ΔT ) which is a value of 0 or less, the initial temperature increase correction value is set to 0;
6. The motor control device according to claim 4, wherein when the corrected substrate temperature difference is equal to or greater than the temperature difference critical value, the initial temperature increase correction value is set equal to the temperature increase stored value. The first rise temperature correction unit (403)
The substrate temperature storage value, the substrate temperature current value, the outside air temperature storage value, and the outside air temperature current value are converted into a temperature value represented by a difference from a reference temperature (To) outside a predetermined processing target temperature range. Based on the substrate temperature ratio (αs), which is the ratio between the temperature memory value and the substrate temperature current value, and the outside air temperature ratio (αg), which is the ratio between the outside air temperature memory value and the outside air temperature current value, The motor control device according to claim 1, wherein the corrected substrate temperature ratio (αs_comp) as an argument is calculated. The reference temperature is set on the low temperature side of the processing target temperature range,
A value obtained by dividing the substrate temperature current value by the substrate temperature stored value is defined as the substrate temperature ratio, and a value obtained by dividing the current outside air temperature value by the outside air temperature stored value is defined as the outside air temperature ratio.
The initial temperature rise correction unit calculates the corrected substrate temperature ratio by dividing the substrate temperature ratio by the outside air temperature ratio, and decreases the initial temperature rise correction value as the corrected substrate temperature ratio decreases. The motor control device according to claim 7, wherein   The motor control device according to claim 8, wherein the first temperature rise correction unit treats the post-correction substrate temperature ratio as 1 when the post-correction substrate temperature ratio is greater than one. The initial temperature rise correction unit is
When the corrected substrate temperature ratio is less than the temperature ratio critical value (C _α ) which is a value of 1 or less, the initial temperature rise correction value is set to 0;
10. The motor control device according to claim 8, wherein when the post-correction substrate temperature ratio is equal to or greater than the temperature ratio critical value, the initial temperature increase correction value is set equal to the temperature increase memory value. A drive circuit (60) for driving the motor (80);
A substrate (20) on which the drive circuit is mounted;
A substrate temperature sensor (71) for detecting the temperature (Ts) of the substrate;
A substrate temperature acquisition unit (31) for acquiring a substrate temperature detected by the substrate temperature sensor;
An outside air temperature acquisition unit (33) for acquiring the outside air temperature (Tg) detected by the outside air temperature sensor (73);
A temperature rise estimation unit (37) for estimating a temperature rise (Ti) of an element of the drive circuit based on a value of a current flowing through the motor or the drive circuit;
A rise temperature storage section (38) for storing the rise temperature estimated by the rise temperature estimation section as a rise temperature storage value (Ti_m);
A current limit value calculation unit (51) that calculates a current limit value so as to limit a current to be supplied to the motor as the temperature rises, based on the rise temperature estimated by the rise temperature estimation unit;
In the initial control at the time of restart after the drive of the motor is stopped by the drive circuit, the elevated temperature memory value is corrected based on the internal / external temperature value (Tdif) obtained by subtracting the current outside air temperature from the current substrate temperature. An initial temperature rise correction unit (405) for calculating a temperature rise correction value (Ti_comp);
With
The first temperature rise correction unit corrects the first temperature rise correction value to be smaller as the internal / external temperature difference is smaller. The first rise temperature correction unit sets the first rise temperature correction value to 0 when the inside / outside temperature difference is less than the inside / outside temperature difference critical value (Cdif),
12. The motor control device according to claim 11, wherein when the internal / external temperature difference is equal to or greater than the internal / external temperature difference critical value, the initial temperature increase correction value is set equal to the temperature increase memory value.

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