Control device

Abstract

A control device (10) for a vehicle (MV) includes: a position information estimation unit (11) that estimates commutation position information for each of a first phase, a second phase, and a third phase in a rotating electric machine (30); an operation control unit (12) that controls the operation of the rotating electric machine (30) based on the estimated commutation position information; and an angular acceleration estimation unit (13) that estimates the angular acceleration of the rotating electric machine. When causing the rotating electric machine to perform a forward rotation operation, the angular acceleration estimation unit estimates the angular acceleration of the rotating electric machine by a first estimation method, and when causing the rotating electric machine to perform a reverse rotation operation for preparatory processing, the angular acceleration estimation unit estimates the angular acceleration of the rotating electric machine by a second estimation method that estimates a value of the angular acceleration of the rotating electric machine to be smaller than that of the first estimation method.

Description

[0001] Cross-references to related applications

[0002] This application is based on Japanese Patent Application No. 2020-096457 filed on June 2, 2020, and claims the benefit of priority thereof, and the entire contents of the patent application are incorporated into this specification by reference. Technical Field

[0003] The present disclosure relates to a control device for a vehicle. Background Art

[0004] In a vehicle having an internal combustion engine, a rotating electric machine for starting the internal combustion engine is provided. This rotating electric machine is generally also called a "starter motor".

[0005] When the internal combustion engine is started by the rotating electric machine, the rotating electric machine operates while resisting the load torque received from the internal combustion engine. Such load torque tends to become particularly large near the position where the crank angle of the internal combustion engine becomes the angle for switching from the compression process to the explosion process. Therefore, for example, when the internal combustion engine is tried to be started by the rotating electric machine in a state where the crank angle is before the above position, the auxiliary starting distance may be insufficient and the internal combustion engine cannot be started beyond the above position.

[0006] Therefore, in the control device described in Patent Document 1 below, when the internal combustion engine is stopped, the rotary electric machine is reversed in advance. Thus, the auxiliary starting distance at the time of starting can be always ensured, so the internal combustion engine can be started stably.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent No. 5929342 Summary of the invention

[0010] However, when controlling a rotating electrical machine that operates with three-phase AC power, it is necessary to estimate or obtain commutation position information about each of the first phase, the second phase, and the third phase, and to control the current of each phase based on the commutation position information. Therefore, a sensor for obtaining the commutation position information and outputting it to the outside is usually built into the rotating electrical machine.

[0011] In addition, the "commutation position information" is information indicating the relative positional relationship between each of the coils of the first phase, second phase, and third phase provided in the stator of the rotating electric machine and the permanent magnet provided in the rotor. Whenever the rotation angle of the rotating electric machine changes by a specified angle (e.g., 180 degrees), the above-mentioned sensor outputs a signal that alternates between L and H as the commutation position information. Generally, this sensor is often provided individually corresponding to each of the coils of the first phase, second phase, and third phase. In this case, the commutation position information corresponding to the first phase, second phase, and third phase is output individually.

[0012] In a rotating electric machine, there are also cases where a sensor for obtaining commutation position information and outputting it to the outside is not provided individually corresponding to each of the coils of the first phase, second phase, and third phase, but only for the first phase. The present inventor has studied a case where a rotating electric machine having such a low-cost structure performs a reverse rotation operation in the same manner as the control described in the above-mentioned Patent Document 1.

[0013] When operating the rotating electric machine having the above structure, since the commutation position information of the second phase and the third phase cannot be obtained from the sensor, it is necessary to estimate them based on the commutation position information of the first phase obtained from the sensor and the like. However, it is generally difficult to always accurately estimate the commutation position information, and sometimes the rotating electric machine may lose synchronization due to the deviation of the estimation. Especially when the rotating electric machine performs a reverse rotation operation before starting the internal combustion engine, the crank angle at the current moment is mostly unclear, and therefore, the rotating electric machine is particularly likely to lose synchronization.

[0014] An object of the present disclosure is to provide a control device that can cause a rotating electric machine provided with a sensor for obtaining commutation position information only for one phase to perform a reverse rotation operation without losing synchronization.

[0015] The control device of the present disclosure is a control device for a vehicle. In the vehicle to be controlled, an internal combustion engine for generating driving force for traveling and a rotary electric machine for starting the internal combustion engine are provided. The control device includes: a position information estimation unit that estimates commutation position information for each of a first phase, a second phase, and a third phase in the rotary electric machine; an operation control unit that controls the operation of the rotary electric machine based on the estimated commutation position information; and an angular acceleration estimation unit that estimates the angular acceleration of the rotary electric machine. The operation control unit is configured to perform a preparation process for causing the rotary electric machine to perform a reverse rotation operation before starting the internal combustion engine. The position information estimation unit estimates the commutation position information for the first phase based on a signal from a commutation sensor provided in the rotary electric machine. On the other hand, the position information estimation unit estimates the commutation position information for each of the second phase and the third phase based on the angular acceleration estimated by the angular acceleration estimation unit with the commutation position information for the first phase as a reference. When causing the rotary electric machine to perform a forward rotation operation, the acceleration estimation unit estimates the angular acceleration of the rotary electric machine by a first estimation method. When causing the rotary electric machine to perform a reverse rotation operation for the preparation process, the acceleration estimation unit estimates the angular acceleration of the rotary electric machine by a second estimation method that calculates a smaller value of the angular acceleration of the rotary electric machine compared to the first estimation method.

[0016] In the control device having such a configuration, the commutation position information for each of the second phase and the third phase is estimated based on the angular acceleration of the rotary electric machine estimated by the angular acceleration estimation unit, and the operation of the rotary electric machine is controlled based on the estimated commutation position information. When causing the rotary electric machine to perform a forward rotation operation, the angular acceleration estimation unit estimates the angular acceleration of the rotary electric machine by a first estimation method. When causing the rotary electric machine to perform a reverse rotation operation for the preparation process, the angular acceleration estimation unit estimates the angular acceleration of the rotary electric machine by a second estimation method that calculates a smaller value of the angular acceleration of the rotary electric machine compared to the first estimation method.

[0017] The angular acceleration of the rotary electric machine estimated by the second estimation method is estimated to be a smaller value compared to the angular acceleration estimated by the first estimation method. Therefore, the commutation position information for the second phase and the third phase estimated based on this angular acceleration is presumed to be switched at a timing later than the actual timing.

[0018] As described above, if a deviation occurs between the estimated commutation position information and the actual commutation position information, the possibility of the rotary electric machine losing synchronization increases. However, based on experiments and the like conducted by the present inventors, the following insight has been obtained: when the commutation position information is presumed to be switched at a timing later than the actual timing, it is less likely to cause loss of synchronization compared to the case where it is presumed to be switched at a timing earlier than the actual timing.

[0019] As described above, when the rotating electric machine performs a reverse rotation operation, if the angular acceleration of the rotating electric machine is estimated by the second estimation method, the commutation position information is not estimated to be switched at a timing earlier than the actual timing. Therefore, the rotating electric machine can perform a reverse rotation operation without causing a step-out.

[0020] According to the present disclosure, a control device can be provided that enables a rotating electric machine having a commutation sensor for acquiring commutation position information provided only for one phase to perform a reverse rotation operation without causing a step-out. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. is a diagram schematically showing the configuration of the control device of the present embodiment and the configuration of a vehicle equipped with the control device.

[0022] Figure 2 FIG. is a diagram schematically showing the configuration of a drive circuit for operating the rotating electric machine.

[0023] Figure 3 FIG. is a diagram showing an example of the change over time of a signal indicating commutation position information or the like.

[0024] Figure 4 FIG. is a diagram for explaining a method of estimating commutation position information.

[0025] Figure 5 FIG. is a diagram for explaining the load torque applied to the rotating electric machine.

[0026] Figure 6 FIG. is a flowchart showing the flow of processing executed by the control device.

[0027] Figure 7 FIG. is a flowchart showing the flow of processing executed by the control device.

[0028] Figure 8 FIG. is a flowchart showing the flow of processing executed by the control device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Hereinafter, the present embodiment will be described with reference to the drawings. For ease of explanation, the same reference numerals are used to denote the same components in the respective drawings as much as possible, and redundant explanations are omitted.

[0030] The control device 10 of the present embodiment is mounted on the vehicle MV and is configured as a device for performing various controls in the vehicle MV. In this control, for example, it includes control for starting the internal combustion engine 20, operation control of the internal combustion engine 20 after starting, and the like.

[0031] In Figure 1FIG. schematically shows the structure of the vehicle MV and the control device 10. As shown in this figure, the vehicle MV includes an internal combustion engine 20 and a rotating electric machine 30. The internal combustion engine 20 is a device for generating driving force for the vehicle MV to travel by burning fuel. The internal combustion engine 20 is configured as a four-stroke reciprocating engine.

[0032] The rotating electric machine 30 is a so-called "starting motor", which is a device for rotating the crankshaft (not shown) of the internal combustion engine 20 to start the internal combustion engine 20. The rotating electric machine 30 is configured as a three-phase motor and operates by receiving supply of three-phase AC power including U-phase, V-phase, and W-phase. As will be described later, the operation of the rotating electric machine 30 is controlled by the control device 10. The rotating electric machine 30 includes a commutation sensor 31 and a drive circuit 300.

[0033] The commutation sensor 31 is configured as a sensor for acquiring commutation position information of the W-phase among the above-mentioned U-phase, V-phase, and W-phase and outputting a signal corresponding to this information. The "commutation position information" is information indicating the relative positional relationship between the coils of the U-phase, V-phase, and W-phase provided in the stator of the rotating electric machine 30 and the permanent magnets provided in the rotor. That is, it is information indicating the rotation angle (i.e., phase) of the rotor of the rotating electric machine 30. In the present embodiment, every time the rotation angle of the rotating electric machine 30 changes by 180 degrees, the above-mentioned commutation position information is used as information that alternately switches between L and H. Depending on the structure of the rotating electric machine 30, the angle of "180 degrees" can also be changed.

[0034] Such commutation position information is information that should be estimated separately for each phase, but only the commutation position information of the W-phase is detected by the commutation sensor 31. The W-phase for which the commutation position information is detected by the commutation sensor 31 corresponds to the "first phase" in the present embodiment. The V-phase and U-phase other than this correspond to the "second phase" and "third phase" in the present embodiment, respectively. In addition, in Figure 1 FIG., the commutation sensor 31 is schematically depicted at a position away from the rotating electric machine 30, but in reality, the commutation sensor 31 is built into the rotating electric machine 30.

[0035] The drive circuit 300 is a circuit for adjusting the power of the U-phase, V-phase, and W-phase supplied to the rotating electric machine 30 to adjust the operation of the rotating electric machine 30. The operation of the drive circuit 300 is controlled by the control device 10.

[0036] As Figure 2As shown, the drive circuit 300 is configured as an inverter circuit having six switching elements 311, 312, 321, 322, 331, and 332. The switching elements 311 and 312 are elements for adjusting the power of the U-phase, which is the third phase. The switching element 311 is arranged at the position of the upper arm of the U-phase, and the switching element 312 is arranged at the position of the lower arm of the U-phase.

[0037] The switching elements 321 and 322 are elements for adjusting the power of the V-phase, which is the second phase. The switching element 321 is arranged at the position of the upper arm of the V-phase, and the switching element 322 is arranged at the position of the lower arm of the V-phase.

[0038] The switching elements 331 and 332 are elements for adjusting the power of the W-phase, which is the first phase. The switching element 331 is arranged at the position of the upper arm of the W-phase, and the switching element 332 is arranged at the position of the lower arm of the W-phase.

[0039] In Figure 2 the component marked with the reference numeral "350" is a storage battery provided in the vehicle MV. The drive circuit 300 converts the DC power supplied from this storage battery into three-phase AC power by causing the switching elements 311, etc. to perform opening and closing operations respectively, and supplies it to the rotating electric machine 30. The opening and closing operations of the switching elements 311, etc. are controlled by the control device 10.

[0040] Continuing to refer to Figure 1 , the structure of the control device 10 will be described. The control device 10 is configured as a computer system having a CPU, a ROM, a RAM, etc. The control device 10 includes a position information estimation unit 11, an operation control unit 12, and an angular acceleration estimation unit 13 as module elements representing its functions.

[0041] The position information estimation unit 11 is a part that performs processing for estimating the commutation position information of each of the W-phase (first phase), V-phase (second phase), and U-phase (third phase) in the rotating electric machine 30. As described above, in the rotating electric machine 30, a commutation sensor 31 for detecting the commutation position information of the W-phase is provided. Therefore, the position information estimation unit 11 estimates the commutation position information of the W-phase based on the signal from the commutation sensor 31. On the other hand, the position information estimation unit 11 estimates the commutation position information of each of the V-phase and U-phase based on the angular acceleration of the rotating electric machine 30 with the commutation position information of the W-phase as a reference. As the "angular acceleration of the rotating electric machine 30", the value estimated by the angular acceleration estimation unit 13 described later is used. The specific method for the position information estimation unit 11 to estimate the commutation position information will be described later.

[0042] The operation control unit 12 is a part that controls the operation of the rotating electric machine 30 based on the commutation position information of each of the W-phase, V-phase, and U-phase estimated by the position information estimation unit 11. The operation control unit 12 controls the operation of the rotating electric machine 30 by controlling the opening and closing operations of switching elements 311 and the like included in the drive circuit 300.

[0043] The angular acceleration estimation unit 13 is a part that performs a process of estimating the angular acceleration of the rotating electric machine 30. As described above, the angular acceleration estimated by the angular acceleration estimation unit 13 is used for the estimation of the commutation position information performed by the position information estimation unit 11. The specific method for the angular acceleration estimation unit 13 to estimate the angular acceleration of the rotating electric machine 30 will be described later.

[0044] In addition, the control device 10 having the above-described configuration may be configured as a single device, or may be configured as a plurality of devices that operate in cooperation with each other. The specific device configuration of the control device 10 for implementing the functions described below is not particularly limited.

[0045] For the control device 10, in addition to the commutation sensor 31, signals from various sensors provided in the vehicle MV are also input thereto. In Figure 1 , as one of these sensors, the crank angle sensor 21 is shown. The crank angle sensor 21 is a sensor for detecting the rotation angle of the crankshaft (not shown) of the vehicle MV, that is, the crank angle. The control device 10 can acquire the value of the crank angle at the current time based on the signal from the crank angle sensor 21.

[0046] Refer to Figure 3 to describe the change in the commutation position information and the like during the operation of the rotating electric machine 30. Figure 3 (A) shown in is an example of the change in the commutation position information of the W-phase. As described above, the commutation position information of the W-phase is detected by the commutation sensor 31. Whenever the rotation angle of the rotating electric machine 30 changes by 180 degrees, as in the example of Figure 3 (A), the commutation sensor 31 outputs a signal that alternates between H and L.

[0047] Figure 3 (B) shown in is an example of the change in the commutation position information of the V-phase. In addition, Figure 3 (C) shown in is an example of the change in the commutation position information of the U-phase. As described above, in the rotating electric machine 30, no sensor for detecting the commutation position information of these two phases is provided. Therefore, Figure 3 the commutation position information shown in (B) of and Figure 3 the commutation position information shown in (C) of cannot be directly detected by the sensor, but is estimated by the position information estimation unit 11.

[0048] In each of the W-phase, V-phase, and U-phase, the timing at which the commutation position information switches between H and L is a timing that is each deviated by a specified angle from each other in the rotational angle of the rotor. The above-mentioned "specified angle" is 1 / 3 of the angle of the range in which the commutation position information is constant and does not change, that is, 60 degrees in the present embodiment.

[0049] For example, in Figure 3 the example of, at the timing (arrow AR1) when the rotational angle of the rotor changes by 60 degrees from the timing when the commutation position information of the W-phase changes from L to H, the commutation position information of the U-phase changes from H to L. Further, at the timing (arrow AR3) when the rotational angle of the rotor changes by 60 degrees from this timing, the commutation position information of the V-phase changes from L to H. At the timing (arrow AR4) when the rotational angle of the rotor changes by 60 degrees from this timing, the commutation position information of the W-phase changes from H to L again.

[0050] In addition, in the rotating electrical machine 30, a sensor for detecting the rotational angle of the rotor with high resolution is not provided. Therefore, the position information estimating unit 11 cannot estimate the change in the commutation position information of the V-phase and U-phase based on the change in the rotational angle of the rotor. As will be described later, the position information estimating unit 11 is configured to calculate the elapsed time required until the change in the commutation position information of each phase based on the angular acceleration estimated by the angular acceleration estimating unit 13, and estimate the change timing of the commutation position information based on this elapsed time.

[0051] If the commutation position information of each phase is estimated as in Figure 3 (A) of Figure 3 (B) of Figure 3 (C) of

[0052] Figure 3 (D) of, the operation control unit 12 controls the operation of the rotating electrical machine 30 based on them. Figure 3 An example of the opening and closing operation of the switching element 331 disposed at the position of the upper arm that becomes the W-phase is shown in

[0053] Figure 3 (E) of. In this example, the switching element 331 is controlled to switch to the closed state (ON) at the timing when the commutation position information of the W-phase shown in Figure 3 (A) changes from L to H, and switches to the open state (OFF) at the timing when the commutation position information changes from H to L.

[0054] Figure 3 An example of the opening / closing operation of the switching element 321 disposed at the position of the upper arm that becomes the V phase is shown in (F). In this example, the switching element 321 is controlled to switch to the closed state (ON) at the timing when the commutation position information of the V phase shown in (B) changes from L to H, and to switch to the open state (OFF) at the timing when the commutation position information changes from H to L. Figure 3 An example of the opening / closing operation of the switching element 321 disposed at the position of the upper arm that becomes the V phase is shown in (F). In this example, the switching element 321 is controlled to switch to the closed state (ON) at the timing when the commutation position information of the V phase shown in (B) changes from L to H, and to switch to the open state (OFF) at the timing when the commutation position information changes from H to L.

[0055] Figure 3 An example of the opening / closing operation of the switching element 322 disposed at the position of the lower arm that becomes the V phase is shown in (G). In this example, the switching element 322 is controlled to switch to the open state (OFF) at the timing when the commutation position information of the V phase shown in (B) changes from L to H, and to switch to the closed state (ON) at the timing when the commutation position information changes from H to L. Figure 3 An example of the opening / closing operation of the switching element 322 disposed at the position of the lower arm that becomes the V phase is shown in (G). In this example, the switching element 322 is controlled to switch to the open state (OFF) at the timing when the commutation position information of the V phase shown in (B) changes from L to H, and to switch to the closed state (ON) at the timing when the commutation position information changes from H to L.

[0056] Figure 3 An example of the opening / closing operation of the switching element 311 disposed at the position of the upper arm that becomes the U phase is shown in (H). In this example, the switching element 311 is controlled to switch to the closed state (ON) at the timing when the commutation position information of the U phase shown in (C) changes from H to L, and to switch to the open state (OFF) at the timing when the commutation position information changes from L to H. Figure 3 An example of the opening / closing operation of the switching element 311 disposed at the position of the upper arm that becomes the U phase is shown in (H). In this example, the switching element 311 is controlled to switch to the closed state (ON) at the timing when the commutation position information of the U phase shown in (C) changes from H to L, and to switch to the open state (OFF) at the timing when the commutation position information changes from L to H.

[0057] Figure 3 An example of the opening / closing operation of the switching element 312 disposed at the position of the lower arm that becomes the U phase is shown in (I). In this example, the switching element 312 is controlled to switch to the open state (OFF) at the timing when the commutation position information of the U phase shown in (C) changes from H to L, and to switch to the closed state (ON) at the timing when the commutation position information changes from L to H. Figure 3 An example of the opening / closing operation of the switching element 312 disposed at the position of the lower arm that becomes the U phase is shown in (I). In this example, the switching element 312 is controlled to switch to the open state (OFF) at the timing when the commutation position information of the U phase shown in (C) changes from H to L, and to switch to the closed state (ON) at the timing when the commutation position information changes from L to H.

[0058] The operation control unit 12 causes the switching elements 311, etc. to perform opening / closing operations at the timings based on the changes in the commutation position information of each phase as in the above example, thereby causing the rotating electric machine 30 to operate. In addition, the operation control unit 12 also performs the following processing: adjusting the torque generated by the rotating electric machine 30 by shifting the timings for switching the opening / closing of the switching elements 311, etc. from the timings of the changes in the commutation position information of each phase. As such a specific method for controlling the operation of the rotating electric machine 30 based on the changes in the commutation position information of each phase, various known methods can be adopted.

[0059] Next, a method for the angular acceleration estimation unit 13 to estimate the angular acceleration of the rotating electric machine 30 will be described. The angular acceleration estimation unit 13 estimates the angular acceleration of the rotating electric machine 30 using one of two methods consisting of a first estimation method and a second estimation method.

[0060] In the first estimation method, the angular acceleration α1 is estimated by the following equation (1).

[0061] α1 = (T M − T L ) / I... (1)

[0062] “T M ” in Equation (1) is the value of the driving torque generated by the rotating electric machine 30. Such T M can be calculated, for example, based on the opening and closing timing of a switching element 311 or the like as in the example of Figure 3 . Alternatively, it can be calculated based on the measured values of the voltage and current of the electric power supplied to the rotating electric machine 30 for the above-mentioned T M . Moreover, the target value of the driving torque when the operation control unit 12 controls the rotating electric machine 30 can be used as the above-mentioned T M .

[0063] “T L ” in Equation (1) is the value of the load torque that the rotating electric machine 30 receives when rotating the internal combustion engine 20. The value of such T L corresponds to each value of the crank angle and is obtained in advance through experiments or the like. The control device 10 can calculate the value of the load torque T L at the current time based on the crank angle detected by the crank angle sensor 21. “I” in Equation (1) is the moment of inertia of the component rotated by the rotating electric machine 30.

[0064] In the second estimation method, the angular acceleration α2 is estimated by the following equation (2).

[0065] α2 = (T M − max(T L )) / I... (2)

[0066] Equation (2) is an equation obtained by replacing “T L ” in Equation (1) with “max(T L )”. max(T L ) is the maximum value of T L that changes with the operation of the rotating electric machine 30. Specifically, max(T L ) is the load torque T L that varies when the operation control unit 12 causes the rotating electric machine 30 to perform a reverse rotation operation for the preparation process described later.The maximum value that can be taken. α2 calculated by Equation (2) represents the angular acceleration of the rotating electric machine 30 when the load torque becomes the maximum value within its operating range. Therefore, the value of α2 is presumed to be smaller than the value of α1. In other words, the second estimation method can be referred to as an estimation method that estimates a smaller value for the angular acceleration of the rotating electric machine 30 compared to the first estimation method.

[0067] In addition, the value of max(T L ) can be obtained in advance through calculation or experiment while considering various factors that may affect the load torque. As such factors, for example, the frictional resistance between the components constituting the internal combustion engine 20 and the inertial resistance of these components can be cited. In addition, as factors that may be considered when calculating the value of max(T L ), the spring force of the valve springs provided at the intake valve and exhaust valve (both not shown) provided in the internal combustion engine 20, the viscosity of the lubricating oil supplied to the internal combustion engine 20, the pumping resistance when pumping the cooling water supplied to the internal combustion engine 20, the rotational resistance when rotating the cooling fan used to blow air into the cooler, etc. can also be cited.

[0068] A method for the position information estimation unit 11 to estimate the commutation position information will be described. In Figure 4 (A), an example of the change in the commutation position information regarding the W phase is shown in the same way as (A) of the previous Figure 3 . In Figure 4 (B), an example of the change in the commutation position information regarding the V phase is shown in the same way as (B) of the previous Figure 3 . In Figure 4 (C), an example of the change in the commutation position information regarding the U phase is shown in the same way as (C) of the previous Figure 3 .

[0069] In the example of Figure 4 , the timing at which the commutation position information regarding the W phase is switched from L to H is represented as time t1. After time t1, the timing at which the commutation information regarding the U phase is switched from H to L is represented as time t2. After time t2, the timing at which the commutation information regarding the V phase is switched from L to H is represented as time t3. After time t3, the timing at which the commutation position information regarding the W phase is switched from H to L is represented as time t4.

[0070] As described above, in each of the W phase, V phase, and U phase, the timing at which the commutation position information is switched between L and H is a timing that is offset by 60 degrees from each other in the rotational angle of the rotor of the rotating electric machine 30. That is, every time the rotational angle of the rotor changes by 60 degrees, the timings of the above times t1, t2, t3, and t4 come in sequence.

[0071] Therefore, assuming that the rotating electric machine 30 rotates at a constant angular velocity (i.e., with an angular acceleration of 0), the periods α from time t1 to time t2, β from time t2 to time t3, and γ from time t3 to time t4 are all periods of the same length.

[0072] In this case, if the length of the period in which the commutation position information regarding the W phase is changed to L before time t1 is set as TM, the lengths of the periods α, β, and γ should each be 1 / 3 of TM. Therefore, the timing when a period of TM / 3 has elapsed since the time t1 when the change of the commutation position information regarding the W phase from L to H is detected by the commutation sensor 31 can be presumed as the timing (time t2) when the commutation position information regarding the U phase is changed from H to L. Similarly, the timing when a period of TM / 3 has further elapsed since time t2 can be presumed as the timing (time t3) when the commutation position information regarding the V phase is changed from L to H.

[0073] However, the angular acceleration of the rotating electric machine 30 does not become 0 in many cases. For example, when the value of the angular acceleration is positive and the angular velocity of the rotating electric machine 30 gradually increases, the period α is shorter than TM / 3, for example, (TM / 3) / K. Similarly, the period β becomes even shorter, for example, (TM / 3) / K 2 . The period γ also becomes even shorter, for example, (TM / 3) / K 3 . In addition, "K" in the above values is a value greater than 1.0 and is a constant determined corresponding to the angular acceleration of the rotating electric machine 30. The greater the angular acceleration of the rotating electric machine 30, the greater the value of K becomes. Therefore, as long as the angular acceleration of the rotating electric machine 30 is obtained, the value of K can be set based on the angular acceleration, and the lengths of the periods α, β, and γ can be calculated using this K.

[0074] The position information estimation unit 11 determines the value of the above-mentioned K based on the angular acceleration of the rotating electric machine 30 estimated by the angular acceleration estimation unit 13. After that, the position information estimation unit 11 uses the determined value of K to calculate the lengths of the periods α, β, and γ as in the above example.

[0075] As long as the time t1 obtained from the commutation position information regarding the W phase, that is, the signal from the commutation sensor 31, is used as a reference, and the lengths of the periods α, β, and γ calculated as above are used, the timings of the times t2 and t3 can be presumed. That is, the time t3 can be presumed as the timing for switching the commutation position information regarding the V phase, and the time t2 can be presumed as the timing for switching the commutation position information regarding the U phase. The position information estimation unit 11 presumes the commutation position information of each phase based on the angular acceleration of the rotating electric machine 30 by the above method.

[0076] A description will be given of the process executed by the operation control unit 12 when starting the internal combustion engine 20. In Figure 5 , the relationship between the phase of the crank angle (horizontal axis) and the load torque received by the rotating electric machine 30 from the internal combustion engine 20 is shown. When starting the internal combustion engine 20, due to the driving force of the rotating electric machine 30, the crank angle changes towards the Figure 5 right side. The direction of this change is the same as the direction in which the crank angle changes when the internal combustion engine 20 is operating. Hereinafter, the operation of the rotating electric machine 30 that changes the crank angle in this direction will also be referred to as a "forward rotation operation".

[0077] As Figure 5 shown, the load torque during the forward rotation operation of the rotating electric machine 30 gradually increases in the compression process and becomes maximum at the timing of switching from the compression process to the explosion (combustion) process. In Figure 5 , such peak values of the load torque are represented as "PK1" and "PK2".

[0078] In addition, there is also a timing at which the load torque increases, in addition to the above-mentioned timing. Figure 5 "PK3" shown in

[0079] is the peak value of the load torque generated due to the rise of the intake valve in the middle of the intake process. Although such a peak value is smaller than PK1 and PK2, it may affect the control of the rotating electric machine 30, and thus cannot be ignored. Figure 5 When starting the internal combustion engine 20, when the initial crank angle is P1 at

[0080] , immediately after the rotating electric machine 30 starts the forward rotation operation, the load torque increases sharply. In this case, since the assist start distance is insufficient, the rotating electric machine 30 may not be able to start the internal combustion engine 20 beyond the peak value PK1 of the load torque.

[0081] Therefore, in the control device 10 of the present embodiment, the operation control unit 12 causes the rotating electric machine 30 to perform a reverse rotation operation in advance before starting the internal combustion engine 20. The "reverse rotation operation" is an operation of the rotating electric machine 30 that rotates in the direction opposite to the forward rotation operation. Thus, hereinafter, the process of causing the rotating electric machine 30 to perform a reverse rotation operation before starting the internal combustion engine 20 will also be referred to as a "preparation process". Figure 5 When the initial crank angle is P1 at Figure 5In the case of the value indicated by the dashed line DL1, the rotation electric machine 30 stops at the moment when the crank angle becomes P2. The stop of the rotation electric machine 30 can be determined based on, for example, a signal from the crank angle sensor 21.

[0082] After that, if the operation control unit 12 causes the rotation electric machine 30 to perform a forward rotation operation, after the rotation electric machine 30 reaches a sufficient rotation speed, the crank angle reaches PK1, so that the internal combustion engine 20 can be operated to cross PK1. That is to say, if preparatory processing is performed in advance, a sufficient start assist distance can be ensured from the position of P2, thereby enabling the internal combustion engine 20 to be started stably against the load torque.

[0083] In the preparatory processing, the crank angle P2 at which the reverse rotation operation of the rotation electric machine 30 stops is a known value that can be obtained in advance through experiments or the like. Therefore, at the timing when the reverse rotation operation of the rotation electric machine 30 stops, the control device 10 can grasp the crank angle at the current moment. After that, since the value of the crank angle can be continuously grasped based on the signal from the crank angle sensor 21, the control device 10 can stably control the operation of the rotation electric machine 30 based on the crank angle.

[0084] In addition, the grasp of the crank angle at the current moment can be performed at the timing when the reverse rotation operation of the rotation electric machine 30 stops as described above, or can be performed at the timing when the signal from the crank angle sensor 21 becomes a signal indicating the passing of a missing tooth. In any case, after the reverse rotation operation is completed, the control device 10 can stably control the operation of the rotation electric machine 30 based on the crank angle.

[0085] In other words, during the period when the control device 10 cannot grasp the current crank angle before the reverse rotation operation is completed, it is difficult to stably control the operation of the rotation electric machine 30. In particular, when passing through the position of PK3 during the reverse rotation operation, an error may occur in the estimated value of the angular acceleration due to an increase in the load torque that cannot be predicted based on the crank angle, and the rotation electric machine 30 may experience a step-out due to this error.

[0086] Therefore, in the control device 10 of the present embodiment, the rotation electric machine 30 is controlled during the reverse rotation operation by a method different from the control method during the forward rotation operation, thereby preventing the rotation electric machine 30 from stepping out.

[0087] The specific content of the control executed by the control device 10 will be described. Figure 6 The series of processes shown are executed at the timing when the power switch of the vehicle MV is turned on (ON). The "power switch" is a switch (not shown) provided in the vehicle MV, and is a switch that is turned on (ON) in advance by the driver's operation at a moment earlier than starting the internal combustion engine 20. Therefore, at the start Figure 6 At the moment of the series of processes shown, the internal combustion engine 20 is in a stopped state.

[0088] In the initial step S01, preparatory processing is performed. As described above, in the preparatory processing, by causing the rotation motor 30 to perform a reverse rotation operation, a boost start distance for a subsequent forward rotation operation is ensured.

[0089] In step S02 following step S01, it is determined whether the start switch has been operated. The "start switch" is a switch (not shown) provided in the vehicle MV and is a switch operated by the driver to start the internal combustion engine 20. If the start switch has not been operated, the processing of step S02 is performed again. If the start switch has been operated, the process proceeds to step S03. In step S03, processing for starting the internal combustion engine 20 is performed. Here, the internal combustion engine 20 is started by causing the rotation motor 30 to perform a forward rotation operation, that is, a so-called start.

[0090] Figure 7 The flowchart of represents the Figure 6 The specific processing flow performed in step S03. In the initial step S11, the action control unit 12 performs processing to start the forward rotation operation of the rotation motor 30. The action control unit 12 causes the switching element 311 of the drive circuit 300 to perform an opening and closing operation as described with reference to Figure 3 Since three-phase AC power is supplied from the drive circuit 300 to the rotation motor 30, the rotation motor 30 thus starts to perform a forward rotation operation.

[0091] In step S12 following step S11, the angular acceleration of the rotation motor 30 is estimated by the angular acceleration estimation unit 13. Here, the angular acceleration is estimated by using the first estimation method described above.

[0092] In addition, at the moment of entering Figure 6 step S03 and starting the Figure 7 series of processes shown, preparatory processing is performed in advance. Therefore, the control device 10 is in a state where it can grasp the current value of the crank angle based on the signal from the crank angle sensor 21. Therefore, when estimating the angular acceleration α1 using Equation (1), the load torque T L can be obtained as an accurate value corresponding to the crank angle, and this estimation is performed simultaneously. That is, the value of the angular acceleration estimated in step S12 is substantially the same as the actual value of the angular acceleration.

[0093] In step S13 following step S12, the commutation position information is estimated for each of the W phase, V phase, and U phase by the position information estimation unit 11, and the commutation timing for each phase is set. The "commutation timing" mentioned here is the timing at which the commutation position information switches between L and H, and is Figure 4 the moments t2, t3, etc. in the example of Figure 4according to the lengths of the periods α and β in the example

[0094] In step S14 following step S13, the operation of the rotary electric machine 30 is controlled according to the commutation timing of each phase set in step S13. As a result, the forward rotation operation of the rotary electric machine 30 started in step S11 continues continuously and stably thereafter.

[0095] Through the preparatory processing performed in advance, the rotary electric machine 30 sufficiently ensures the Figure 5 boost starting distance before reaching PL1. Therefore, the starting of the internal combustion engine 20 by the rotary electric machine 30 is not hindered by the load torque.

[0096] In step S15 following step S14, it is determined whether the starting of the internal combustion engine 20 has been completed. This determination can be made based on a signal from the crank angle sensor 21. When it is determined that the starting of the internal combustion engine 20 has not been completed, the processing after step S12 is executed again, and the forward rotation operation of the rotary electric machine 30 is continued. When it is determined that the starting of the internal combustion engine 20 has been completed, the process proceeds to step S16. In step S16, a process of stopping the forward rotation operation of the rotary electric machine 30 is executed.

[0097] Next, the specific content of the preparatory processing will be described. Figure 8 The flowchart shows the Figure 6 flow of the specific processing performed in step S01. In the initial step S21, the operation control unit 12 performs a process of starting the reverse rotation operation of the rotary electric machine 30. This process is the same as Figure 7 step S11, but is different from Figure 7 step S11 in the rotation direction of the rotary electric machine 30. Through this process, the rotary electric machine 30 starts to perform the reverse rotation operation.

[0098] In step S22 following step S21, the angular acceleration of the rotary electric machine 30 is estimated by the angular acceleration estimation unit 13. Here, the angular acceleration is estimated by using the second estimation method described above.

[0099] In addition, at the moment when the series of processes shown in Figure 8 is started, the control device 10 does not accurately grasp the crank angle at the current moment. Therefore, if it is assumed that the first estimation method is not used and the second estimation method is used to estimate the angular acceleration in step S22, the load torque T of Equation (1) cannot be obtained L as an accurate value corresponding to the crank angle. Therefore, the value of the estimated angular acceleration and the actual angular acceleration deviate significantly, and control is performed based on incorrect commutation position information, and as a result, there is a possibility of out-of-step of the rotary electric machine 30.

[0100] Therefore, in the present embodiment, as described above, when the rotary electric machine 30 performs a reverse rotation operation during the preparation process, the angular acceleration is estimated by using the second estimation method. In the second estimation method, as described with reference to Equation (2), the angular acceleration α2 is estimated on the basis of setting the load torque to a constant value of max(T L ). Such α2 is a value smaller than α1 based on the first estimation method, and thus is estimated to be a value smaller than the actual angular acceleration. Therefore, the commutation position information of each of the V-phase and U-phase estimated based on α2 is estimated to be switched at a timing later than the actual timing.

[0101] The present inventors have obtained the following insight: When the commutation position information is estimated to be switched at a timing later than the actual timing, it is less likely to cause loss of synchronization compared to the case where it is estimated to be switched at a timing earlier than the actual timing. If the angular acceleration α2 is estimated to be a value smaller than the actual angular acceleration as described above, then even in a situation where the accurate load torque corresponding to the crank angle cannot be grasped, the commutation position information of each phase is not estimated to be switched at a timing earlier than the actual timing. Therefore, in the present embodiment, the rotary electric machine 30 can perform a reverse rotation operation without causing loss of synchronization.

[0102] In step S23 following step S22, in the same manner as in Figure 7 step S13 of, the commutation position information of each of the W-phase, V-phase, and U-phase is estimated by the position information estimation unit 11, and the commutation timing of each phase is set. The setting of the commutation timing is performed by calculating Figure 4 the lengths of the respective periods α and β in the example of.

[0103] In step S24 following step S23, the operation of the rotary electric machine 30 is controlled according to the commutation timing of each phase set in step S23. As a result, the reverse rotation operation of the rotary electric machine 30 started in step S21 continues continuously and stably thereafter.

[0104] In step S25 following step S24, it is determined whether the crank angle that has changed due to the operation of the rotary electric machine 30 has reached the stop position. As described with reference to Figure 5 , when the load torque that changes according to the crank angle exceeds the torque of the rotary electric machine 30, the rotary electric machine 30 stops. Thus, if the rotary electric machine 30 stops, it is determined in step S25 that the stop position has been reached.

[0105] Instead of such a method, for example, it may also be determined that the crank angle has reached the stop position when the signal from the crank angle sensor 21 becomes a signal indicating the passage of a missing tooth, or when a predetermined angle has further changed after the passage of the missing tooth.

[0106] In step S25, when it is determined that the crank angle has not reached the stop position, the processes after step S22 are executed again, and the reverse rotation operation of the rotation motor 30 is continued. When it is determined that the crank angle has reached the stop position, the process proceeds to step S26. In step S26, the process of causing the rotation motor 30 to perform the reverse rotation operation is stopped.

[0107] As described above, in the control device 10 of the present embodiment, when the rotation motor 30 performs a forward rotation operation, the angular acceleration estimation unit 13 estimates the angular acceleration of the rotation motor 30 by the first estimation method, and when the rotation motor 30 performs a reverse rotation operation for preparatory processing, the angular acceleration estimation unit 13 estimates the angular acceleration of the rotation motor 30 by the second estimation method. Thus, when the rotation motor 30 is caused to perform a reverse rotation operation in advance before the start of the internal combustion engine 20, the reverse rotation operation can be stably performed without losing synchronization.

[0108] As shown in equations (1) and (2), the angular acceleration estimation unit 13 estimates the angular acceleration of the rotation motor 30 based on the difference between the driving torque (T M ) generated by the rotation motor 30 and the load torque (T L , max(T L )) received by the rotation motor 30 when rotating the internal combustion engine 20. Further, when the angular acceleration estimation unit 13 estimates the angular acceleration α2 by the second estimation method, the value of the load torque is set to a larger value than when the angular acceleration of the rotation motor 30 is estimated by the first estimation method. That is, the value of the load torque subtracted from T L in equation (2) is set to be larger than T L and is set to max(T L ). Thus, the angular acceleration α2 is estimated to be a value smaller than the actual angular acceleration, and a stable reverse rotation operation of the rotation motor 30 can be achieved.

[0109] The above-mentioned max(T L ) is a constant value that does not change with the passage of time (which can also be said to be the change in the crank angle). When estimating the angular acceleration α2 by equation (2), max(T L ) can also be replaced with another constant value different therefrom. Even in such a manner, the same effect as the effect described above can be achieved.

[0110] Further, the second estimation method may also be a method different from equation (2). For example, it may be an estimation method that calculates a fixed value sufficiently smaller than α1 as the value of α2. It may also be an estimation method that always calculates 0 as the above-mentioned fixed value.

[0111] When executing Figure 8During the preparatory process, the control device 10 can calculate the actual angular acceleration of the rotating electric machine 30, for example, based on the period of the signal switching from the commutation sensor 31. Therefore, when the difference between the actually calculated angular acceleration and the angular acceleration α2 calculated by Figure 8 step S22 is too large, the value of the angular acceleration α2 can be appropriately corrected to reduce this difference. Conversely, when the above difference is too small, the value of the angular acceleration α2 can be appropriately corrected to increase this difference. In any case, the corrected value of the angular acceleration α2 is set to a value smaller than the actual angular acceleration or the value of the angular acceleration α1 estimated by the first estimation method.

[0112] In addition, in the present embodiment, as described with reference to Figure 6 after turning on (ON) the power switch of the vehicle MV, a preparatory process for causing the rotating electric machine 30 to perform a reverse rotation operation is executed. Instead of this method, the preparatory process can also be executed during the period from turning off (OFF) the power switch when the vehicle MV stops running to turning on (ON) the power switch for the next run. In this way, the timing for executing the preparatory process for causing the rotating electric machine 30 to perform a reverse rotation operation only needs to be earlier than the start of the internal combustion engine 20. If it is such a timing, the start of the internal combustion engine 20 will not be delayed due to the execution of the preparatory process, and thus, the driver will not feel discomfort.

[0113] The present embodiment has been described with reference to specific examples. However, the present disclosure is not limited to these specific examples. For the solutions obtained by appropriately designing and changing these specific examples by those skilled in the art, as long as they still have the features of the present disclosure, they are included in the scope of the present disclosure. The elements, their configurations, conditions, shapes, etc. of each of the foregoing specific examples are not limited to the illustrated cases and can be appropriately changed. For the elements of each of the foregoing specific examples, as long as there is no technical contradiction, the combinations can be appropriately changed.

[0114] The control device and control method described in the present disclosure can also be implemented by one or more of the following dedicated computers: the one or more dedicated computers are provided by a processor and a memory programmed to execute one or more functions embodied by a computer program. The control device and control method described in the present disclosure can also be implemented by the following dedicated computer: the dedicated computer is provided by a processor comprising one or more dedicated hardware logic circuits. The control device and control method described in the present disclosure can also be implemented by one or more of the following dedicated computers: the one or more dedicated computers are constituted by a combination of a processor and a memory programmed to execute one or more functions and a processor comprising one or more hardware logic circuits. The computer program can also be stored as instructions executable by a computer in a computer-readable non-transitory tangible recording medium. The dedicated hardware logic circuits and the hardware logic circuits can also be implemented by a digital circuit or an analog circuit comprising a plurality of logic circuits.

Claims

1. A control device, which is a control device of a vehicle, is characterized in that in the vehicle, an internal combustion engine for generating driving force for traveling and a rotary electric machine for starting the internal combustion engine are provided, the control device includes: a position information estimation unit that estimates commutation position information for each of a first phase, a second phase, and a third phase in the rotary electric machine; an operation control unit that controls the operation of the rotary electric machine based on the estimated commutation position information; and an angular acceleration estimation unit that estimates the angular acceleration of the rotary electric machine; the operation control unit is configured to perform a preparation process of causing the rotary electric machine to perform a reverse rotation operation in advance before starting the internal combustion engine, the position information estimation unit estimates the commutation position information for the first phase based on a signal from a commutation sensor provided in the rotary electric machine, on the other hand, the position information estimation unit estimates the commutation position information for each of the second phase and the third phase based on the angular acceleration estimated by the angular acceleration estimation unit with the commutation position information for the first phase as a reference, when causing the rotary electric machine to perform a forward rotation operation, the angular acceleration estimation unit estimates the angular acceleration of the rotary electric machine by a first estimation method, when causing the rotary electric machine to perform a reverse rotation operation for performing the preparation process, the angular acceleration estimation unit estimates the angular acceleration of the rotary electric machine by a second estimation method that estimates a value of the angular acceleration of the rotary electric machine to be smaller than that of the first estimation method.

2. The control device according to claim 1, characterized in that the angular acceleration estimation unit estimates the angular acceleration of the rotary electric machine based on a difference between a driving torque generated by the rotary electric machine and a load torque received by the rotary electric machine when rotating the internal combustion engine, in the case of estimating the angular acceleration of the rotary electric machine by the second estimation method, compared with the case of estimating the angular acceleration of the rotary electric machine by the first estimation method, a value of the load torque is set to be larger.

3. The control device according to claim 2, characterized in that the angular acceleration estimation unit sets the value of the load torque to a constant value that does not change with the passage of time in the case of estimating the angular acceleration of the rotary electric machine by the second estimation method.

4. The control device according to claim 3, characterized in that the angular acceleration estimation unit sets the maximum value that the variable load torque can take as the constant value when the operation control unit causes the rotary electric machine to perform a reverse rotation operation for performing the preparation process.

Images