Control device

Abstract

To provide a controller of a rotary electric machine capable of performing control for suppressing the fluctuation of the rotation frequency of an internal combustion engine in a stable manner.SOLUTION: A rotary electric machine 30 has a movable part 31 applying a torque to a drive shaft 21 of an internal combustion engine 20. A controller 10 of the rotary electric machine 30 comprises: a signal acquisition unit 11 for acquiring a rotation frequency signal which is a signal changing in accordance with the rotation frequency of the movable part 31 per unit time; and a torque calculation unit 12 for calculating a vibration control torque applied by the movable part 31 to the drive shaft 21 to suppress vibration while the internal combustion engine 20 is operating. The torque calculation unit 12 calculates the vibration control torque on the basis of the rotation frequency signal acquired by the signal acquisition unit 11 while the rotary electric machine 30 performs cranking on the internal combustion engine 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a control device for a rotating electrical machine.

Background Art

[0002] For example, in a generator mounted on an electric vehicle or the like, an internal combustion engine and a rotating electrical machine are provided. In such a generator, when the movable part of the rotating electrical machine rotates due to the torque generated by the internal combustion engine, power generation is performed by the rotating electrical machine. At this time, if a periodically pulsating torque is generated in the rotating electrical machine, the fluctuation of the rotational speed of the internal combustion engine can be suppressed by the torque. Thereby, it becomes possible to suppress vibrations of the internal combustion engine or the like that occur with fluctuations in the rotational speed.

[0003] The following Patent Document 1 describes adjusting the output torque of a rotating electrical machine according to the resistance torque of an internal combustion engine, thereby suppressing vibrations.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In an operating internal combustion engine, an explosion occurs at the timing when the piston reaches top dead center or at a timing close thereto. For this reason, the periodic torque output from the rotating electrical machine to suppress vibrations is preferably minimized at that timing.

[0006] As a method for the control device of the rotating electrical machine to grasp the above timing, for example, it is conceivable to receive a signal indicating the piston position from a control device (engine ECU) that controls an internal combustion engine. However, in such a configuration, for example, if there is a communication delay between control devices via a communication network such as an in-vehicle network, it may become impossible to change the torque of the rotating electrical machine at an appropriate timing. Also, if the communication is interrupted for some reason, the control to suppress the rotational speed fluctuations of the internal combustion engine by the rotating electrical machine will be completely disabled.

[0007] An object of the present disclosure is to provide a control device for a rotating electrical machine that can stably perform control to suppress fluctuations in the rotational speed of an internal combustion engine.

Means for Solving the Problem

[0008] The control device according to the present disclosure is a control device (10) for a rotating electrical machine (30). The rotating electrical machine has a movable part (31) that applies torque to the drive shaft (21) of the internal combustion engine (20). This control device includes a signal acquisition unit (11) that acquires a rotational speed signal, which is a signal that changes according to the rotational speed of the movable part per unit time, and a torque calculation unit (12) that calculates a vibration damping torque applied from the movable part to the drive shaft in order to suppress vibration during the operation of the internal combustion engine. The torque calculation unit calculates the vibration damping torque based on the rotational speed signal acquired by the signal acquisition unit when cranking of the internal combustion engine by the rotating electrical machine is being performed.

[0009] In the control device having such a configuration, when cranking of the internal combustion engine by the rotating electrical machine is being performed, that is, before the internal combustion engine is started, the signal acquisition unit acquires the rotational speed signal. Such a rotational speed signal is a signal that varies according to the position of the piston of the internal combustion engine, and thus includes information indicating the piston position of the internal combustion engine. Therefore, the torque calculation unit can calculate an appropriate vibration damping torque synchronized with the piston position of the internal combustion engine by calculating the vibration damping torque based on the rotational speed signal.

[0010] Further, the rotational speed signal is not acquired by communication from a control device that controls an internal combustion engine, but can be directly acquired, for example, based on a signal from a sensor provided in a rotating electrical machine. Therefore, the signal acquisition unit can always stably acquire the rotational speed signal without being affected by communication interruption or the like. Thereby, the control device can stably perform control to suppress fluctuations in the rotational speed of the internal combustion engine.

Advantages of the Invention

[0011] According to the present disclosure, there is provided a control device for a rotating electrical machine that can stably perform control to suppress fluctuations in the rotational speed of an internal combustion engine.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0013] Hereinafter, this embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same reference numerals are given to the same components in each drawing as much as possible, and redundant descriptions are omitted.

[0014] The control device 10 according to this embodiment is a device mounted on the generator PG, and is configured as a device for controlling the operation of the rotating electrical machine 30 provided in the generator PG. Prior to the description of the control device 10, the configuration of the generator PG will be described first.

[0015] The generator PG is a device mounted on a vehicle such as an electric vehicle, and generates electric power necessary for the running of the vehicle. Examples of such a vehicle configuration include a series hybrid vehicle. Note that the generator PG may be a generator mounted on a vehicle as described above, or may be a stationary generator installed in a building, for example. As shown in FIG. 1, the generator PG includes an internal combustion engine 20, a rotating electrical machine 30, an inverter 40, a storage battery 50, and an inverter 60.

[0016] The internal combustion engine 20 is a device that burns fuel to generate torque (rotational force of the drive shaft 21), and is a so-called reciprocating engine. The internal combustion engine 20 is provided with four cylinders (not shown). Inside each cylinder, a piston that reciprocates up and down is arranged. The up-and-down movement of the piston is converted into the rotational movement of the drive shaft 21. The drive shaft 21 is also referred to as a "crankshaft". Note that the number of cylinders provided in the internal combustion engine 20 may be different from four.

[0017] The rotating electrical machine 30 is a device that generates electricity by the torque received from the internal combustion engine 20, and is also referred to as a "motor generator". The rotating electrical machine 30 has a movable part 31. When the movable part 31 rotates due to the torque received from the internal combustion engine 20, three-phase AC power is generated in the rotating electrical machine 30. This power is supplied to the inverter 40. In the present embodiment, the drive shaft 21 of the internal combustion engine 20 and the movable part 31 of the rotating electrical machine 30 are directly connected. That is, the movable part 31 is fixed to the drive shaft 21. In the present embodiment, the rotating electrical machine 30 has an outer rotor structure, but it may have other structures.

[0018] The statement "the movable part 31 is fixed to the drive shaft 21" as used herein means that there is no intervening member such as a flywheel for stabilizing the rotational speed, a damper for reducing the pulsation of the rotational speed, or a gear for changing the rotational speed between the drive shaft 21 and the movable part 31. For this reason, the rotational speed of the drive shaft 21 per unit time and the rotational speed of the movable part 31 per unit time always match each other. In addition, if these rotational speeds match each other, a clutch for temporarily releasing the connection between the two may be provided between the drive shaft 21 and the movable part 31. Such a mode is also included in the configuration where "the movable part 31 is fixed to the drive shaft 21". In the following description, the rotational speed per unit time may be simply referred to as the "rotational speed".

[0019] Although the rotating electrical machine 30 operates by receiving the torque from the internal combustion engine 20 as described above, it can also rotate the movable part 31 by receiving power supply from the outside. In this case, the movable part 31 applies torque to the drive shaft 21 of the internal combustion engine 20. At the start of the internal combustion engine 20, an operation of rotating the drive shaft 21 of the internal combustion engine 20 by the rotating electrical machine 30, that is, a so-called "cranking" is performed.

[0020] After the internal combustion engine 20 is started, that is, when the movable part 31 is rotating under the torque from the internal combustion engine 20, the rotating electrical machine 30 according to this embodiment can also suppress fluctuations in the rotational speeds of the movable part 31 and the drive shaft 21 by generating pulsating torque in the movable part 31. Thereby, vibrations during the operation of the internal combustion engine 20 are suppressed. The torque generated as described above in the rotating electrical machine 30 is also referred to as "vibration damping torque" hereinafter. The vibration damping torque can be said to be the torque applied from the movable part 31 of the rotating electrical machine 30 to the drive shaft 21 of the internal combustion engine 20 in order to suppress vibrations during the operation of the internal combustion engine 20. How the vibration damping torque is calculated and output will be described later.

[0021] A rotational speed sensor 32 for detecting the rotational speed of the movable part 31 is provided near the movable part 31. The rotational speed sensor 32 is, for example, a resolver provided in the rotating electrical machine 30, but other sensors may also be used. A signal indicating the rotational speed of the movable part 31 is input from the rotational speed sensor 32 to the control device 10.

[0022] The inverter 40 is a power converter that converts the AC power generated in the rotating electrical machine 30 into DC power and supplies the DC power to the storage battery 50. The inverter 40 can also convert DC power from the storage battery 50 into AC power and supply the AC power to the rotating electrical machine 30. Thus, the inverter 40 is configured as a bidirectional power converter. The operation of the inverter 40 is controlled by the control device 10. The control device 10 can adjust the torque, rotational speed, etc. of the rotating electrical machine 30 by controlling the operation of the inverter 40.

[0023] The storage battery 50 is for temporarily storing the electric power output from the generator PG to the outside, and is, for example, a lithium ion battery. The AC power generated by the rotating electric machine 30 is converted into DC power by the inverter 40 as described above, and then supplied to and stored in the storage battery 50. Also, a part of the power stored in the storage battery 50 may be supplied to the rotating electric machine 30 via the inverter 40 and used as power for generating vibration damping torque in the rotating electric machine 30. Incidentally, the vibration damping torque may be generated by adjusting the regenerative power generated in the rotating electric machine 30 with the inverter 40 without using the power from the storage battery 50. The control device 10 can acquire the state of the storage battery 50 by communicating with a control device (not shown) mounted on the storage battery 50.

[0024] The inverter 60 is a power converter for converting the power stored in the storage battery 50 into AC power and outputting it to the outside. For example, when the generator PG is mounted on an electric vehicle, the power output from the inverter 60 is supplied to a rotating electric machine (not shown) for running mounted on the electric vehicle. In this case, a configuration may be adopted in which the regenerative power generated during braking of the electric vehicle is supplied to the storage battery 50 via the inverter 60. The operation of the inverter 60 is controlled by the control device 10.

[0025] Continuing to refer to FIG. 1, the configuration of the control device 10 will be described. As described above, the control device 10 is configured as a device for controlling the operation and the like of the rotating electric machine 30 provided in the generator PG. The control device 10 is configured as a computer system having a CPU, a ROM, and the like. The control device 10 includes, as blocks schematically representing its functions, a signal acquisition unit 11, a torque calculation unit 12, a torque adjustment unit 13, and an information acquisition unit 14.

[0026] The signal acquisition unit 11 is a part that performs a process of acquiring from the rotation speed sensor 32 a signal that changes according to the rotation speed of the movable part 31. This signal is hereinafter also referred to as the "rotation speed signal". In the present embodiment, since the drive shaft 21 and the movable part 31 are directly connected, the rotation speed signal can also be said to be a signal that changes according to the rotation speed of the drive shaft 21.

[0027] The torque calculation unit 12 is a part that performs a process of calculating the vibration damping torque described above. The torque calculation unit 12 calculates the magnitude of the vibration damping torque to be output in order to suppress vibration during the operation of the internal combustion engine 20 by a method to be described later.

[0028] The torque adjustment unit 13 is a part that performs a process of adjusting the torque of the movable part 31, that is, the torque actually output from the rotary electric machine 30. The torque adjustment unit 13 controls the operation of the inverter 40 so that the rotation speed of the movable part 31 matches a predetermined target value, thereby adjusting the torque of the movable part 31. Further, the vibration damping torque calculated by the torque calculation unit is superimposed on the torque of the movable part 31 adjusted by the torque adjustment unit 13. That is, the torque adjustment unit 13 controls the operation of the inverter 40 so that the torque actually output from the rotary electric machine 30 becomes a torque obtained by superimposing the vibration damping torque on the torque required to match the rotation speed of the movable part 31 to a predetermined target value.

[0029] The information acquisition unit 14 is a part that performs a process of acquiring information indicating the advance angle amount or retard angle amount of the internal combustion engine 20 by communicating with a control device (not shown) that controls the internal combustion engine 20. The "information indicating the advance angle amount or retard angle amount of the internal combustion engine 20" is information representing the difference between the timing when the piston reaches the top dead center in the cylinder of the internal combustion engine 20 and the timing when ignition is performed in the cylinder, in terms of the change amount of the crank angle. This information is hereinafter also referred to as the "angle information".

[0030] Furthermore, the acquisition of the angle information by the information acquisition unit 14 may be performed in a manner different from the above. For example, the information acquisition unit 14 may previously store a map showing the correspondence between the operating state (e.g., rotational speed) of the internal combustion engine 20 and the advance angle amount or retard angle amount of the internal combustion engine 20, and the information acquisition unit 14 may acquire the angle information by referring to the map.

[0031] With reference to FIG. 2, the outline of the processing performed by the torque adjustment unit 13 or the like to adjust the torque of the rotating electrical machine 30 will be described.

[0032] The rotational speed signal from the rotational speed sensor 32 is converted into the actual rotational speed by the arithmetic block 109 and then input to the subtracter 101. In the subtracter 101, a process of subtracting the actual rotational speed from the target rotational speed, which is the target value of the rotational speed of the movable part 31, is performed. The difference between the target rotational speed and the actual rotational speed is converted into a torque command value of the rotating electrical machine 30 by the PI controller 102. The torque command value is input to the arithmetic block 105 indicating the vector control system via the adder 103 described later. The torque command value is converted into command values (Vu, Vv, Vw) for the current values of each of the u-phase, v-phase, and w-phase in the arithmetic block 105, and the command values are input to the inverter 40. From the inverter 40, currents (Iu, Iv, Iw) of each phase composed of the u-phase, v-phase, and w-phase are supplied to the rotating electrical machine 30 based on the respective command values to operate the rotating electrical machine 30. The current Iv of the v-phase and the current Iw of the w-phase are measured by the current sensors 107 and 108, respectively, and fed back to the arithmetic block 105.

[0033] By performing the control as described above, the torque of the rotating electrical machine 30 is adjusted to generally match the target rotational speed. However, the movable part 31 of the rotating electrical machine 30 is connected to the drive shaft 21 of the internal combustion engine 20. Therefore, the rotational speed of the movable part 31 does not exactly remain constant and fluctuates under the influence of the torque from the internal combustion engine 20.

[0034] Therefore, the control device 10 of the present embodiment superimposes a vibration damping torque as a torque for suppressing the above-described fluctuations in the rotational speed. The vibration damping torque calculated by the torque calculation unit 12 is input from the arithmetic block 104 in FIG. 2 to the adder 103 and added to the torque command value output from the PI arithmetic unit 102. As a result, the vibration damping torque is superimposed on the torque necessary to match the rotational speed of the movable part 31 to a predetermined target value.

[0035] The torque of the internal combustion engine 20 will be described with reference to FIG. 3. FIG. 3 shows an example of changes in various torques (vertical axis) of the internal combustion engine 20 when the crank angle (horizontal axis) of the internal combustion engine 20 changes. The torque indicated by the line L1 in FIG. 3 is the torque generated due to the explosion of fuel in each cylinder of the internal combustion engine 20. The torque indicated by the line L1 is hereinafter also referred to as "in-cylinder pressure torque".

[0036] The torque indicated by the line L2 in FIG. 3 is the torque generated due to the inertial force when the piston moves up and down in each cylinder of the internal combustion engine 20. The torque indicated by the line L2 is hereinafter also referred to as "reciprocating mass inertia torque". The torque indicated by the line L3 in FIG. 3 is the torque obtained by adding the in-cylinder pressure torque indicated by the line L1 and the reciprocating mass inertia torque indicated by the line L2.

[0037] In FIG. 3, d1, d2, d3, and d4 all represent the crank angles at the timing when the piston reaches the top dead center in each cylinder. Since the explosion of fuel occurs immediately after each timing indicated by d1 etc., the torque of the internal combustion engine 20 indicated by the line L3 becomes maximum at almost the same timing as each timing of d1 etc. Therefore, it is preferable that the torque calculation unit 12 calculates the vibration damping torque so that the pulsating vibration damping torque becomes minimum at the timing when the torque of the internal combustion engine 20 indicated by the line L3 becomes maximum. In order to calculate the vibration damping torque as such a pulsating torque, it is necessary for the control device 10 to grasp the timings such as d1 when the piston reaches the top dead center in each cylinder by some method.

[0038] The timings such as d1 when the piston reaches the top dead center in each cylinder can be obtained through communication from a control device that controls the operation of the internal combustion engine 20, such as an engine ECU. However, when configured to obtain timings in such a way, if a communication delay occurs between control devices via a communication network such as an in-vehicle network, there is a possibility that the vibration damping torque cannot be appropriately output from the rotating electrical machine 30. Also, if communication is interrupted for some reason, the control to suppress the rotational speed fluctuation of the internal combustion engine 20 by the rotating electrical machine 30 will be completely disabled.

[0039] Therefore, in the control device 10 according to the present embodiment, without using the information obtained by communication from the engine ECU, by using the rotational speed signal from the rotational speed sensor 32, the vibration damping torque is pulsated so as to change at an appropriate timing (phase).

[0040] The timing at which the vibration damping torque is calculated and output will be described with reference to FIG. 4. FIG. 4(A) is a graph showing an example of the time change of the rotational speed in the movable part 31. In this example, during the period until time t2, cranking is performed by the rotating electrical machine 30, and the internal combustion engine 20 is started at time t2. Among the periods during which cranking is being performed, during the period until time t1, the rotational speed of the movable part 31 increases with the passage of time, and at time t1, it reaches a predetermined target rotational speed Rt. After time t1, the rotational speed of the movable part 31 is maintained at the target rotational speed Rt. In the example of FIG. 4, the target rotational speed Rt remains constant even after time t2, but after the internal combustion engine 20 is started, the target rotational speed Rt may be appropriately changed.

[0041] Line L11 in Fig. 4(B) is a graph showing an example of the time change of the torque generated by the rotating electrical machine 30. Also, line L12 in Fig. 4(B) is a graph showing an example of the time change of the torque generated by the internal combustion engine 20. As shown by line L12, the torque generated by the internal combustion engine 20 is 0 in the period before the time t2 when the internal combustion engine 20 is started. After the time t2, a positive torque is generated by the internal combustion engine 20.

[0042] As shown by line L11, when cranking is performed in the period up to the time t2, a positive torque is generated by the rotating electrical machine 30. The torque rapidly rises and then falls immediately after the start of cranking, and is maintained at a positive value necessary to maintain the rotational speed of the movable part 31 at the target rotational speed Rt.

[0043] At the time t2, ignition is performed in the internal combustion engine 20, and after the internal combustion engine 20 is started, a negative torque is generated by the rotating electrical machine 30. The torque is a torque that resists the torque of the internal combustion engine 20 and is necessary to maintain the rotational speeds of the drive shaft 21 and the movable part 31 at the target rotational speed Rt. In Fig. 4(B), the line L11 after the time t2 is drawn linearly, but the actual torque change has a pulsating waveform due to the influence of the superimposed vibration damping torque.

[0044] In the present embodiment, the calculation of the vibration damping torque by the torque calculation unit 12 is performed in the period up to the time t2 when the internal combustion engine 20 is started, that is, in the period when cranking is performed. In this period, the vibration damping torque is only calculated and not actually output. That is, in this period, only the torque necessary to maintain the rotational speed of the movable part 31 at the target rotational speed Rt is output from the rotating electrical machine 30, and the vibration damping torque is not superimposed on the torque.

[0045] From time t2, the torque adjustment unit 13 starts to superimpose the vibration damping torque on the torque output from the rotary electric machine 30. The vibration damping torque is a torque having a waveform such that the value of the vibration damping torque becomes minimum at the timing when the torque of the internal combustion engine 20 indicated by line L3 (or line L2 in FIG. 3) is maximized, and is prepared in advance during the period up to time t2. For this reason, from the timing (time t2) immediately after the internal combustion engine 20 is started, the vibration during the operation of the internal combustion engine 20 can be appropriately suppressed.

[0046] A method for the torque calculation unit 12 to calculate the vibration damping torque during the period up to time t2 will be described with reference to FIG. 5. FIG. 5(A) shows an example of the change in the reciprocating mass inertia torque in the internal combustion engine 20. FIG. 5(B) shows an example of the change in the rotational speed of the movable part 31. FIG. 5(C) shows an example of the change in the torque generated in the rotary electric machine 30. FIG. 5(D) shows an example of the change in the vibration damping torque calculated by the torque calculation unit 12. Each graph shown in FIG. 5 represents an example of the time change of each parameter during the period before the internal combustion engine 20 is started. Therefore, the vibration damping torque in FIG. 5(D) is only prepared and not actually output yet.

[0047] During the period before the internal combustion engine 20 is started, in the internal combustion engine 20, the in-cylinder pressure torque shown by line L1 in FIG. 3 is not generated, and only the reciprocating mass inertia torque shown by line L2 in FIG. 3 and FIG. 5(A) is generated. As shown in both figures, the reciprocating mass inertia torque changes in a sine wave shape with the passage of time.

[0048] In FIG. 5, the timings at which the pistons reach the top dead center in each cylinder are shown as times t10, t20, t30, and t40. As shown in FIG. 5(A), due to its nature, the reciprocating mass inertia torque becomes 0 at each timing (times t10, etc.) when the piston reaches the top dead center, and changes so as to switch from the positive direction to the negative direction at that timing.

[0049] During the period when cranking is being performed, specifically, in the period after time t1 in Fig. 4(A), the control device 10 attempts to control the operation of the rotating electrical machine 30 via the inverter 40 so that the rotational speed of the movable part 31 matches a constant target rotational speed Rt. However, due to the influence of the reciprocating mass inertia torque that varies as shown in Fig. 5(A), the rotational speed of the movable part 31 pulsates as shown in Fig. 5(B). The rotational speed of the movable part 31 changes in a sine wave shape similar to the reciprocating mass inertia torque.

[0050] However, the phase of the rotational speed is a phase that is delayed by 1 / 4 cycle from the phase of the reciprocating mass inertia torque. Therefore, the rotational speed of the movable part 31 changes so as to reach a maximum value at each timing (such as time t10) when the piston reaches top dead center. At this time, the torque generated by the rotating electrical machine 30 changes as shown in Fig. 5(C) as a result of the control by the control device 10. The torque generated by the rotating electrical machine 30 changes in a sine wave shape similar to the reciprocating mass inertia torque. Also, the phase of the torque is the same phase as the phase of the reciprocating mass inertia torque.

[0051] The change in the rotational speed of the movable part 31 shown in Fig. 5(B), that is, the rotational speed signal acquired by the signal acquisition unit 11, is affected by the reciprocating mass inertia torque shown in Fig. 5(A) as described above. As a result, the rotational speed signal is a signal that varies according to the position of the piston of the internal combustion engine 20 and includes information indicating the piston position of the internal combustion engine 20. Therefore, the torque calculation unit 12 calculates an appropriate vibration damping torque synchronized with the piston position of the internal combustion engine 20 based on the rotational speed signal that changes as shown in Fig. 5(B).

[0052] The specific calculation method is as follows. The torque calculation unit 12 calculates the vibration damping torque that changes with time using the following formula (1). Vibration damping torque = A × sin(ω × t + φ + θ) ····(1)

[0053] "A" in Equation (1) is the amplitude of the vibration damping torque. The torque calculation unit 12 determines the amplitude A of the vibration damping torque, for example, by referring to a map showing the correspondence between the rotational speed of the movable part 31 and the amplitude.

[0054] "ω" in Equation (1) is the angular velocity in the change of the vibration damping torque. The torque calculation unit 12 calculates the angular velocity ω, for example, using the following Equation (2). ω = RR × n / 2 ····(2)

[0055] "RR" in Equation (2) is a numerical value representing the rotational speed of the movable part 31 in units of radians per second. "n" in Equation (2) is the number of cylinders of the internal combustion engine 20. In this embodiment, n = 4.

[0056] "t" in Equation (1) is the elapsed time (seconds) from a specific time (for example, the time when cranking starts). The torque calculation unit 12 continuously calculates the value of the vibration damping torque so that it is always the latest value while updating t according to the current time.

[0057] "φ" in Equation (1) is a parameter for correcting the phase of the vibration damping torque. The torque calculation unit 12 adjusts the value of φ so that the timing at which the value of the vibration damping torque becomes minimum approaches the timing (time t10, etc.) at which the piston reaches the top dead center in each cylinder. The torque calculation unit 12 corrects the vibration damping torque in such a way and approaches the ideal vibration damping torque.

[0058] In the example shown in FIG. 4(D), the value of the vibration damping torque is minimum at time t9 before the time t10 when the piston reaches the top dead center. Therefore, the torque calculation unit 12 decreases φ in Equation (1) by, for example, a predetermined amount so that the period Δt1 from time t9 to time t10 becomes shorter. The said process is performed, for example, immediately after time t10.

[0059] As a result, the period Δt2 from the time t19 when the value of the vibration damping torque next becomes minimum to the time t20 when the piston reaches the top dead center is shorter than Δt1. The torque calculation unit 12 decreases φ in Expression (1) by a predetermined amount again so that the period Δt2 becomes even shorter. As a result, the period Δt3 from the time t29 when the value of the vibration damping torque next becomes minimum to the time t30 when the piston reaches the top dead center is even shorter than Δt2. By repeatedly performing the process of adjusting the value of φ in this way, the torque calculation unit 12 brings the timing at which the value of the vibration damping torque becomes minimum closer to the timing at which the piston reaches the top dead center. By the time cranking ends, the timing at which the value of the vibration damping torque becomes minimum and the timing at which the piston reaches the top dead center can be made to substantially coincide with each other.

[0060] "θ" in Expression (1) is the amount of advance or retard of the internal combustion engine 20. When ignition is performed in the cylinder of the internal combustion engine 20 after the timing at which the piston reaches the top dead center, that is, when the ignition timing is retarded, the value of θ is made negative according to the degree of the retard. Conversely, when the ignition timing is advanced, the value of θ is made positive according to the degree of the advance. The value of θ is set based on the angle information acquired by the information acquisition unit 14. However, in the present embodiment, the value of θ is set to 0 in the period before the vibration damping torque is actually output.

[0061] An example of a specific method for setting φ in Expression (1) will be described. A line L21 shown in FIG. 6 is a graph showing the change in the rotational speed of the movable part 31, that is, the change in the rotational speed shown in FIG. 5(B), after normalization. "Normalization" as used here means adjusting the graph of the change in the rotational speed of the movable part 31 so that the amplitude is ±1 and the center value is 0 while maintaining the phase. Normalization of the rotational speed of the movable part 31 can be performed, for example, by dividing the value obtained by subtracting the target rotational speed Rt from the measured value of the rotational speed of the movable part 31 by the amplitude of the rotational speed at that time. The value represented by the line L21 can be said to be the value of the normalized rotational speed signal.

[0062] The line L22 shown in FIG. 6 is a graph obtained by normalizing the change in the vibration damping torque in the same manner as the line L21. The value represented by the line L22 can be said to be the value of the normalized vibration damping torque.

[0063] If, hypothetically, the timing at which the value of the vibration damping torque becomes minimum and the timing at which the piston reaches the top dead center coincide with each other, the sum of the value of the normalized rotational speed signal (line L21) and the value of the normalized vibration damping torque (line L22) becomes 0. On the other hand, if the respective timings are shifted, the sum of the value of the normalized rotational speed signal (line L21) and the value of the normalized vibration damping torque (line L22) becomes a value other than 0.

[0064] Therefore, if φ is set according to the sum of the value of the normalized rotational speed signal (line L21) and the value of the normalized vibration damping torque (line L22) at a specific timing, it is possible to relatively easily perform the correction of the vibration damping torque by the φ. In this case, the correspondence relationship between the above sum and φ may be stored in advance as a map. As the "specific timing" in the above, for example, the timing at which the value of the rotational speed signal becomes the maximum value or the like can be used.

[0065] In addition, when calculating φ, instead of the value of the normalized rotational speed signal (line L21), it is also possible to use the one obtained by normalizing the change in the torque generated in the rotating electrical machine 30 (FIG. 5(C)). In this case, if the one obtained by performing arithmetic processing to delay the phase thereof by 1 / 4 cycle and then normalizing the change in the torque generated in the rotating electrical machine 30 is used, φ can be calculated in the same manner as above.

[0066] Alternatively, the one obtained by performing arithmetic processing to advance the phase thereof by 1 / 4 cycle and then normalizing the change in the torque generated in the rotating electrical machine 30 may be used. In this case, φ may be set according to the difference between the value of the normalized torque of the rotating electrical machine 30 and the value of the normalized vibration damping torque.

[0067] In order to realize the calculation of the vibration damping torque and the like described above, the specific processing flow executed by the control device 10 will be described with reference to FIG. 7. The series of processes shown in the figure are executed immediately after the cranking of the internal combustion engine 20 by the rotating electrical machine 30 is started.

[0068] In the first step S01 of the process, a process of setting a target rotational speed is performed. This target rotational speed is the target rotational speed Rt in the example of FIG. 4. The target rotational speed may always be set to the same value, or may be set to different values depending on the situation.

[0069] In step S02 following step S01, the calculation of the vibration damping torque by the torque calculation unit 12 is started. Here, the vibration damping torque is calculated using the formula (1) described above. Thereafter, the value of the vibration damping torque is repeatedly calculated and updated using t corresponding to the current time at that point. Incidentally, until step S07 described later is passed, an initial value, which is a provisional value, is used as φ in formula (1). Also, until step S09 described later is passed, θ in formula (1) is set to 0. Incidentally, the vibration damping torque at this point is only calculated and is not actually output yet. The vibration damping torque is output from step S10 described later.

[0070] In step S03 following step S02, it is determined whether or not the rotational speed of the movable part 31 has reached the target rotational speed set in step S01. This determination is made based on, for example, the rotational speed signal acquired by the signal acquisition unit 11.

[0071] If the rotational speed of the movable part 31 has not yet reached the target rotational speed, the process of step S03 is repeated again. If the rotational speed of the movable part 31 has reached the target rotational speed, the process proceeds to step S04. In parallel with this, the control device 10 executes the process described with reference to FIG. 2 so that the rotational speed of the movable part 31 is maintained at the target rotational speed thereafter.

[0072] In step S04, the process of detecting the fluctuation of the rotational speed of the movable part 31 is started. Specifically, the process of obtaining the change in the rotational speed in the movable part 31 as a graph of temporal change that fluctuates as shown in Fig. 5(B) is started.

[0073] In step S05 following step S04, the process of calculating the phase shift is performed. The "phase shift" here refers to the difference between the timing when the piston reaches the top dead center and the timing when the value of the vibration damping torque becomes minimum, as indicated by Δt1, Δt2, etc. in Fig. 5(D).

[0074] In step S06 following step S05, it is determined whether or not the above phase shift is within the allowable range. Specifically, when the absolute value of the phase shift calculated in step S05 is equal to or less than a predetermined threshold value, it is determined that the phase shift is within the allowable range. Otherwise, it is determined that the phase shift exceeds the allowable range.

[0075] In step S06, if it is determined that the phase shift exceeds the allowable range, the process proceeds to step S07. In step S07, the process of correcting the phase of the vibration damping torque is performed. This process is performed by the torque calculation unit 12. Here, with reference to Fig. 6, the value of φ in Equation (1) is updated by the method described above. Thereafter, the processes after step S05 are executed again.

[0076] In step S06, if it is determined that the phase shift is within the allowable range, the process proceeds to step S08. In step S08, the information acquisition unit 14 performs the process of acquiring the angle information. In step S09 following step S08, the torque calculation unit 12 sets the value of θ based on the angle information. Thereafter, the phase of the vibration damping torque calculated by Equation (1) will be corrected using θ.

[0077] When the process of step S09 is completed, the rotational speed of the movable part 31 is generally maintained at the target rotational speed, and the timing at which the value of the vibration damping torque becomes minimum and the timing at which the piston reaches the top dead center coincide with each other. That is, the vibration damping torque is appropriately prepared.

[0078] In step S10 following step S09, ignition in the internal combustion engine 20 is started, and thereby the operation of the internal combustion engine 20 is started. This process is performed by a control device (engine ECU) that controls the internal combustion engine 20 while measuring the timing in cooperation with the control device 10.

[0079] When ignition in the internal combustion engine 20 is started, the control device 10 starts to superimpose the vibration damping torque on the torque output from the rotating electrical machine 30 (that is, the torque of the movable part 31) almost simultaneously therewith. Thereby, since an appropriate vibration damping torque is output from the rotating electrical machine 30 from the beginning when the operation of the internal combustion engine 20 is started, fluctuations in the rotational speed of the internal combustion engine 20 can be suppressed. The timing at which the vibration damping torque starts to be output is preferably the same as the timing at which ignition is performed in the internal combustion engine 20, but may be a timing slightly after ignition is performed in the internal combustion engine 20.

[0080] As described above, in the control device 10 according to the present embodiment, when the torque calculation unit 12 cranks the internal combustion engine 20 by the rotating electrical machine 30 (before time t2 in FIG. 4), the vibration damping torque is calculated based on the rotational speed signal acquired by the signal acquisition unit 11. Further, the torque adjustment unit 13 of the control device 10 starts to superimpose the vibration damping torque on the torque of the movable part 31 at the timing when the internal combustion engine 20 is started (the timing of time t2 in FIG. 4). Thereby, control for suppressing fluctuations in the rotational speed of the internal combustion engine 20 can be stably performed without depending on communication between control devices. Further, since the vibration damping torque is corrected in real time based on the rotational speed signal, fluctuations in the rotational speed of the internal combustion engine 20 can be surely suppressed even when the rotational speeds of the drive shaft 21 and the movable part 31 change.

[0081] The torque calculation unit 12 calculates the vibration damping torque in FIG. 5(D) so as to have a waveform synchronized with the waveform of the rotational speed signal as shown in FIG. 5(B). Specifically, the torque calculation unit 12 calculates the vibration damping torque so that the phase shift (such as Δt1) between the waveform of the rotational speed signal and the waveform of the vibration damping torque approaches 0. Thereby, the waveform of the calculated vibration damping torque becomes an appropriate waveform for suppressing the rotational speed fluctuation of the internal combustion engine 20. Note that the “synchronized waveform” described above means that the period in which the waveform of the rotational speed signal (FIG. 5(B)) reaches the maximum value or the minimum value and the period in which the waveform of the vibration damping torque (FIG. 5(D)) reaches the maximum value or the minimum value coincide with each other.

[0082] As described with reference to FIG. 6, the torque calculation unit 12 sets φ based on the value of the normalized rotational speed signal (line L21 in FIG. 6) and the value of the normalized vibration damping torque (line L22 in FIG. 6), and corrects the phase of the vibration damping torque using the φ. By such a method, the phase shift between the waveform of the rotational speed signal and the waveform of the vibration damping torque can be made close to 0 by a relatively easy calculation.

[0083] In step S09 of FIG. 7, the torque calculation unit 12 corrects the phase of the vibration damping torque based on the angular information. Thereby, it is possible to more accurately match the timing at which the internal pressure of the cylinder in the internal combustion engine 20 reaches the maximum and the timing at which the value of the vibration damping torque reaches the minimum.

[0084] In the present embodiment, in the present embodiment, the drive shaft 21 of the internal combustion engine 20 and the movable part 31 of the rotary electric machine 30 are directly connected using, for example, bolts or the like. That is, the movable part 31 is fixed to the drive shaft 21. In such a configuration, since the rotational speed of the drive shaft 21 coincides with the rotational speed of the movable part 31, it is possible to calculate an appropriate vibration damping torque based on the rotational speed signal. However, even in a configuration in which a gear, a damper, or the like is interposed between the drive shaft 21 and the movable part 31, it is possible to calculate the vibration damping torque in the same manner as in the present embodiment.

[0085] The device to be controlled by the control device 10 may be any device configured such that the internal combustion engine 20 and the rotating electrical machine 30 are connected to each other, and may be a device different from the generator PG as in the present embodiment. For example, the internal combustion engine 20 may be for generating the driving force of a vehicle, and the rotating electrical machine 30 may be a device provided as a dedicated device for suppressing fluctuations in the rotational speed of the internal combustion engine 20. Even in such a device, by the control device 10 performing the same control as in the present embodiment, vibrations during the operation of the internal combustion engine 20 can be suppressed.

[0086] As described above, the present embodiment has been described with reference to specific examples. However, the present disclosure is not limited to these specific examples. Even those obtained by appropriately making design changes to these specific examples by those skilled in the art are included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the above-described specific examples and its arrangement, conditions, shape, etc. are not limited to those illustrated and can be changed as appropriate. Each element included in each of the above-described specific examples can be combined as appropriate as long as no technical contradiction occurs.

[0087] The control device and control method described in the present disclosure may be realized by one or more dedicated computers provided by configuring 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 may be realized by a dedicated computer provided by configuring a processor including one or more dedicated hardware logic circuits. The control device and control method described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor including one or more hardware logic circuits. The computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer. The dedicated hardware logic circuit and the hardware logic circuit may be realized by a digital circuit including a plurality of logic circuits or an analog circuit.

Description of Symbols

[0088] 10: Control device 11: Signal acquisition unit 12: Torque calculation unit 20: Internal combustion engine 21: Drive shaft 30: Rotating electric machine 31: Movable part

Claims

1. A control device (10) for a rotating electrical machine (30), wherein the rotating electrical machine has a movable part (31) that applies torque to a drive shaft (21) of an internal combustion engine (20), a signal acquisition unit (11) that acquires a rotational speed signal, which is a signal that changes according to the rotational speed of the movable part per unit time, and a torque calculation unit (12) that calculates a vibration damping torque applied from the movable part to the drive shaft in order to suppress vibration during operation of the internal combustion engine, wherein the torque calculation unit calculates the vibration damping torque based on the rotational speed signal acquired by the signal acquisition unit when cranking of the internal combustion engine by the rotating electrical machine is being performed, calculates the vibration damping torque so as to have a waveform synchronized with the waveform of the rotational speed signal, and corrects the phase of the vibration damping torque based on the value of the normalized rotational speed signal and the value of the normalized vibration damping torque.

2. further comprising a torque adjustment unit (13) that adjusts the torque of the movable part, wherein the torque adjustment unit starts superimposing the vibration damping torque on the torque of the movable part at the timing when the internal combustion engine is started, the control device according to claim 1.

3. further comprising an information acquisition unit (14) that acquires angle information, which is information indicating an advance angle amount or a retard angle amount of the internal combustion engine, wherein the torque calculation unit corrects the phase of the vibration damping torque based on the angle information, the control device according to claim 1.

4. The control device according to any one of claims 1 to 3, wherein the movable part is fixed to the drive shaft.

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