JP3598190B2 - Power generator for internal combustion engines - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power generator for an internal combustion engine that converts rotational energy of an internal combustion engine (hereinafter, sometimes also referred to as an engine) into electric energy, and in particular, to generate a rotating magnetic field in a multi-phase winding of a rotor. The present invention relates to a power generator for an internal combustion engine which can optimize its own driving torque.
[0002]
[Prior art]
A power generating device for a vehicle or a marine vessel includes an alternator (ACG) having a rotating shaft connected to an engine crankshaft via an alternator belt, and a rectifier for converting the AC power generated by the alternator according to the engine speed into DC power. And a regulator that controls the voltage of the DC power according to the battery voltage.
[0003]
FIG. 9 is a schematic diagram showing the configuration of a conventional alternator 50. A DC field coil 53 is wound around a rotor (rotor) 52 integrated with a rotating shaft, and a stator 54 (stator) is wound around the rotor. Has a three-phase coil 55 wound therearound. Here, when the rotor 52 is rotated in an excited state in which a DC current is supplied from a battery to the DC field coil 53 to form an alternating magnetic field arrangement, the three-phase coil 55 of the stator 54 has a rotation speed corresponding to the rotation speed of the rotor 52. AC power of the frequency is generated. That is, the conventional alternator is a generator using a synchronous motor. The rotor 52 may be provided with a permanent magnet instead of the DC field coil 53.
[0004]
[Problems to be solved by the invention]
In the above-described internal combustion engine for a vehicle or the like, when an electric load having a large power consumption such as a headlight or an air conditioner is turned on / off, the DC field coil 53 is turned on and off in order to increase or decrease the amount of power generation in response thereto. The excitation intensity is also controlled. As a result, the torque required for the engine to drive the alternator (hereinafter simply referred to as drive torque) fluctuates, and the engine speed changes. In particular, when a large electric load is turned on from an off state to an on state, and the driving torque increases sharply, the engine speed decreases accordingly.If the engine is idling, it may cause an engine stall or even during running. In such a case, there arises a problem that drivability is deteriorated due to a kind of braking state.
[0005]
In order to solve such a problem, for example, in Japanese Patent Application Laid-Open No. 1-277650, it is determined whether or not an electric load is applied, and when it is determined that the electric load is applied, a throttle valve is opened to set an engine speed. Control devices for increasing the value have been proposed. Japanese Patent Application Laid-Open No. Hei 5-180047 proposes a control device for controlling the duty ratio of a field current supplied to a field coil of a stator in accordance with an increase or a decrease in an electric load. However, in each of the above-mentioned conventional technologies, since the drive torque of the alternator fluctuates in accordance with the increase or decrease in the electric load, a large load is applied to the alternator belt, or stability is still lacking because quick control cannot be performed. There was a problem.
[0006]
An object of the present invention is to solve the above-described problems of the prior art, employ an induction machine as an alternator, and even if a factor that fluctuates the drive torque of the alternator, such as a change in electric load or engine speed, occurs. It is an object of the present invention to provide a power generator for an internal combustion engine that can control a drive torque arbitrarily.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an induction machine including a rotor having a multi-phase winding and a stator, in which the rotor rotates by transmitting the rotational motion of an internal combustion engine, and a battery charged by the induction machine And a power generation device for an internal combustion engine, which is provided with a rotating magnetic field generating means for generating a rotating magnetic field in a multi-phase winding of a rotor, which is fed from the battery and changes the driving torque of the induction machine such as an increase or decrease of an electric load. Is generated, the rotating magnetic field generating means controls the rotating magnetic field speed so that the increased or decreased electric load can be covered without fluctuation of the driving torque, and then the increased or decreased electric load is changed relative to the stator with respect to the rotating magnetic field. The invention is characterized in that the rotating magnetic field control accompanied by the fluctuation of the driving torque is gradually executed so that the speed can be covered even at the predetermined rotation speed.
[0013]
According to the above-described feature , even if the electric load increases or decreases, it is possible to perform ideal power generation amount control without experiencing a change in driving torque.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
First, the basic concept of the present invention will be described. The substantial rotational speed of the induction machine can be represented by the relative speed N of the rotating magnetic field generated by the rotor with respect to the stator coil, and the field winding (polyphase winding) of the rotor generates a DC magnetic field instead of a rotating magnetic field. The relative speed N is equal to the mechanical rotation speed of the rotor. Here, considering the case where a rotating magnetic field is generated in the multi-phase winding of the rotor, the mechanical rotation speed of the rotor is N1 and the speed of the rotating magnetic field generated in the multi-phase winding of the rotor is N2. The relative speed N is represented by the following equation.
N = N1 + N2 (1)
That is, the relative speed N of the rotating magnetic field generated by the rotor of the induction machine with respect to the stator coil is equal to the rotating direction of the rotating magnetic field generated by the multi-phase winding of the rotor that matches the mechanical rotation direction of the rotor. The rotation speed becomes faster than the mechanical rotation speed N1 of the rotor, and becomes lower than the rotation speed N1 of the rotor if the rotation direction is reversed. Therefore, if the induction machine is used as an alternator for a vehicle, no matter how the mechanical rotation speed N1 of the rotor changes in synchronization with the engine speed, the induction motor is generated in the multiphase winding of the rotor in response to the change. The relative speed N can be arbitrarily controlled by appropriately controlling the rotating magnetic field speed N2.
[0017]
On the other hand, as shown in FIG. 10, since the drive torque T of the alternator can be expressed as a function of the relative speed N, if the relative speed N of the rotating magnetic field can be arbitrarily controlled as described above, Can be arbitrarily controlled regardless of the mechanical rotation speed N1 of the rotor.
[0018]
Thus, in the present invention, if the driving torque T of the induction machine is a function of the relative speed N of the rotating magnetic field to the stator, and the relative speed N can control the rotating magnetic field speed N2 generated in the multi-phase winding of the rotor. Focusing on the fact that control is possible irrespective of the mechanical rotation speed N1 of the rotor, the drive torque of the induction machine can be controlled arbitrarily according to the state of the vehicle and the like.
[0019]
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a main part of a vehicle power generation device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a configuration of an alternator 1 constituting the power generation device of the present invention. (A) is a sectional view on a plane perpendicular to the rotation axis, and (b) is a sectional view on a plane parallel to the rotation axis. The alternator 1 of the present invention is a so-called induction machine in which three-phase windings, that is, three-phase field coils 11 and 12 are formed on the rotor 1R and the stator 1S, respectively.
[0020]
2, a rotor 1R having a three-phase field coil 11 is coaxially fixed to a rotating shaft 13 of the alternator 1, and a stator 1S having a three-phase field coil 12 is provided around the rotor 1R. Are located. The rotating shaft 13 is rotatably supported by the housing 17 via a front bearing 15a and a rear bearing 15b. A pulley 14 is fixed to one end of the rotating shaft 13, and slip rings 18 a to 18 c are formed at the other end to contact brushes 19 a to 19 c for supplying an exciting current to the field coils 11 (11 a to 11 c) of the rotor 1 </ b> R. Have been.
[0021]
In the alternator 1 on the other end side of the rotating shaft 13, a rotor excitation device 2, an ACG / ECU 3, a switching control device 5 and a short-circuit device 8, which will be described later, are mounted on a housing 17 on the same plane orthogonal to the rotating shaft 13. Are arranged side by side in the circumferential direction along the inside. This facilitates the routing of wiring between the devices, enables effective use of dead space, and suppresses the alternator from increasing in size.
[0022]
In FIG. 1, when the ACG ECU 3 communicates with the engine ECU 4 to detect the engine speed Ne, the electric load, and the like, the speed N2 of the rotating magnetic field electrically generated in the rotor 1R, the rotating magnetic field voltage, the rotating magnetic field phase, and the like. Is determined, and the electric rotating magnetic field control unit 2a of the rotor excitation device 2 is notified. The electric rotating magnetic field control unit 2a controls the phase, amplitude, and frequency of AC power supplied to each of the field coils 11a, 11b, 11c of the rotor 1R based on the rotating magnetic field speed N2 and the like notified from the ACG ECU 3. , A rotating magnetic field having a rotation speed N2 is generated electrically.
[0023]
The switching control device 5 communicates with the ACG-ECU 3 to detect the operating state of the alternator 1, and at the timing of functioning as a generator, the output terminal of the alternator 1 is connected to the contact {circle around (1)} of the output control device 7 to operate as a motor. At the functioning timing, each contact of the switching circuit 6 is controlled so as to be connected to the contact (2) of the short circuit device 8. At the timing when the alternator 1 functions as a generator, a part of the output power of the alternator 1 may be supplied to the alternator 1 for self-excitation via the electric rotating magnetic field control unit 2a.
[0024]
The output control device 7 includes a rectifier circuit 7a and a regulator 7b, and converts AC power output from the alternator 1 into DC power according to the voltage of the battery 9. The short-circuit device 8 short-circuits the output terminals of the field coils 12a, 12b, 12c of the alternator 1 via a variable resistor or not. The DC excitation control unit 2b is selectively energized with the electric rotating magnetic field control unit 2a, and supplies DC power to the field coils 11a and 11b of the rotor 1R to generate a magnetic field in the rotor 1R.
[0025]
In such a configuration, when the ACG · ECU 3 is notified of the operating parameters such as the engine speed Ne and the electric load detected by the engine ECU 4, the ACG · ECU 3 changes the rotor 1 R of the alternator 1 based on the engine speed Ne and the pulley ratio. Calculate the mechanical rotation speed N1. Further, the ACG-ECU 3 controls the relative speed N of the rotating magnetic field generated by the rotor 1R with respect to the stator 1S so that the actual driving torque of the alternator 1 falls within the target driving torque range specified by the engine ECU 4. The speed N2 of the rotating magnetic field electrically generated in the three-phase winding of 1R is calculated, and this is notified to the electric rotating magnetic field control unit 2a.
[0026]
The electric rotating magnetic field control unit 2a controls the excitation timing of each phase of the three-phase coil 11 of the rotor 1R to electrically generate a rotating magnetic field of the speed N2. The AC power output from each of the field coils 11a, 11b, 11c of the rotor 1R is converted into DC power by the output control device 7, a part of which is supplied to the current electric load, and the rest is charged into the battery 9. In addition, since the control method of the induction machine itself is known, the description thereof is omitted.
[0027]
Next, a specific example of drive torque control according to the present invention will be described with reference to FIG. FIG. 3A is a diagram illustrating an example of a method of controlling the driving torque in the power generator having the above-described configuration. In the present embodiment, the driving torque of the alternator 1 is limited to an upper limit regardless of the mechanical rotation speed of the rotor 1R. The torque is limited to less than Tmax. Such torque control is performed in accordance with the mechanical rotation speed N1 of the rotor 1R so that the relative speed N is maintained at or below the lower speed limit Na or the lower limit Nb determined by the upper limit torque Tmax. This is achieved by controlling the speed N2 of the rotating magnetic field generated electrically in the three-phase winding of 1R.
[0028]
FIG. 8 is a flowchart showing the operation of the above embodiment. In step S1, the mechanical rotation speed of the alternator 1, that is, the rotor rotation speed N1 is measured. The rotation speed N1 can be calculated based on, for example, the engine rotation speed Ne and the pulley ratio. In step S2, the current drive torque T of the alternator is measured. The driving torque T may be measured by using a torque meter, but can also be measured by measuring the output current and the exciting current of the alternator 1.
[0029]
In step S3, it is determined whether or not the detected drive torque T exceeds the upper limit torque Tmax. If it is determined that the drive torque T has exceeded the upper limit torque Tmax, in step S4, the remaining battery charge is detected based on the battery voltage. Here, since the power generation amount M of the alternator increases with an increase in the relative speed N, in the present embodiment, if it is determined in step S4 that the remaining battery capacity is insufficient (for example, the battery voltage is 12 V or less), In step S5a, a rotating magnetic field speed for increasing the relative speed N and reducing the driving torque T, that is, a rotating magnetic field speed + N2 for making the relative speed N equal to or higher than the high-speed lower limit value Nb is calculated. On the other hand, if it is determined that the remaining battery charge is sufficient (for example, the battery voltage is 12.5 V or more), in step S5b, the relative magnetic field speed for reducing the relative speed N and the driving torque T, that is, the relative speed N The rotating magnetic field speed -N2 for making the lower speed lower limit Na or lower is calculated. In step S6, a rotating magnetic field of speed N2 is induced in the multi-phase winding of the rotor.
[0030]
FIG. 3B is a diagram showing an example of another control method of the driving torque of the alternator 1. In the present embodiment, the driving torque of the alternator 1 is reduced to the lower limit torque Tmin regardless of the mechanical rotation speed of the rotor. I try to keep it above. Such torque control is also achieved by controlling the rotating magnetic field speed N2 according to the mechanical rotation speed N1 of the rotor 1R so that the relative speed N does not fall below the lower limit value N3.
[0031]
FIG. 3C is a diagram showing an example of still another control method of the drive torque. In this embodiment, the drive torque of the alternator is maintained at a constant torque Tc regardless of the mechanical rotation speed of the rotor. I am trying to be. Such torque control is also achieved by controlling the rotating magnetic field speed N2 according to the mechanical rotation speed N1 of the rotor 1R so that the relative speed N always matches the target speed N4.
[0032]
According to the present embodiment, the drive torque T of the alternator can be kept within a desired predetermined value or within a predetermined range irrespective of the rotation speed N1 of the rotor 1R, so that the load on the alternator belt is excessively increased or reduced, or A large change in load can be prevented, and a change in engine speed can also be prevented.
[0033]
By the way, in the alternator, when the temperature decreases, the electric resistance of the multi-phase winding decreases and a large amount of exciting current flows. Therefore, as shown in FIG. 4, the driving torque at the same relative speed is lower at a low temperature than at a high temperature. Will be higher. Therefore, for example, when it is desired to limit the drive torque of the alternator to the upper limit torque Tmax or less, the lower limit value and the lower limit value of the relative speed N are changed from NaH and NbH at high temperature to NaL and NbL at low temperature. . Therefore, if the drive torque T of the alternator is controlled to fall within the target value or the target range based on the relative speed N in the manner described above, the relative speed N and the drive torque T are determined using the temperature of the alternator 1 as a parameter. It is desirable to define the relationship in advance.
[0034]
In each of the control methods described above, the drive torque of the alternator has been described as being controlled to be within an arbitrary absolute range or a value.However, the drive torque is set to be higher or lower than the current drive torque. May be relatively controlled in relation to the driving torque of the induction motor. For example, the rotating magnetic field speed may be controlled so that the driving torque of the induction machine is increased or decreased according to the vehicle state.
[0035]
That is, as in the second embodiment of the present invention shown in FIG. 5, the acceleration state of the vehicle is detected based on the accelerator opening, the engine speed, and the like in the state of the operating point A where the electric load is 40 A, for example. At times, the rotating magnetic field speed N2 is increased by ΔN21 to increase the relative speed N, whereby the operating point is shifted to C to lower the driving torque. Also, when the engine braking state of the vehicle is detected, the relative magnetic field speed N2 is reduced by ΔN22 to reduce the relative speed N, thereby shifting the operating point to B and increasing the driving torque, thereby improving acceleration performance and engine performance. Brake performance is improved.
[0036]
Next, a third embodiment of the present invention will be described. In the above-described first and second embodiments, the electric load of the alternator 1 is not taken into account. However, in actual use, the electric load greatly fluctuates due to on / off of an air conditioner, a headlamp, and the like. The relationship between the relative speed N and the driving torque T also greatly changes. FIG. 6 is a diagram showing the relationship between the relative speed N of the alternator 1 and the driving torque T using the electric load as a parameter. Even if the relative speed N is the same, the driving torque T increases as the electric load increases. I understand.
[0037]
Here, if the electric load increases to 40 A while generating 30 A of electric power at the relative speed N10, the driving torque normally increases from T1 to T2. For this reason, a shock corresponding to the torque fluctuation may be generated in the vehicle, and a temporary decrease in the engine speed due to an increase in the driving torque may be caused. Therefore, in the present embodiment, when the drive torque is likely to fluctuate due to an increase or decrease in the electric load, the increase or decrease in the electric load is compensated for by an increase or decrease in the relative speed N, thereby preventing the torque fluctuation. That is, in the present embodiment, when the electric load increases to 40 A while the electric power of 30 A is generated at the relative speed N10 as described above, the rotating magnetic field speed N2 is increased to increase the relative speed from N10 to N20. As a result, it is possible to increase the power generation from 30 A to 40 A while keeping the driving torque constant.
[0038]
Further, as shown in FIG. 7, the relationship between the relative speed N of the alternator and the power generation efficiency η indicates the maximum efficiency ηmax at a certain point Nx with the relative speed N, and the power generation efficiency η increases as the distance from the maximum efficiency rotation speed Nx increases. Decreases. Therefore, it is desirable to maintain the relative speed N at the rotational speed at which the maximum efficiency ηmax is obtained.
[0039]
Therefore, in the present embodiment, when an event such as an increase or decrease in the electric load that fluctuates the drive torque of the alternator occurs, in order to compensate for the fluctuation without fluctuating the drive torque at first, the multi-phase winding of the rotor is performed. The relative speed N is controlled by changing the speed N2 of the rotating magnetic field that is electrically generated in the line, and thereafter, the relative speed N is increased with the drive torque fluctuation while the power generation amount is kept constant. The rotating magnetic field speed N2 is gradually changed so as to coincide with Nx. At this time, it is desirable that the control of the rotating magnetic field speed N2, that is, the control of the relative speed N, is gradually performed at such a speed that the driving torque fluctuation is not felt by the driver or does not appear as a sudden shock on the alternator belt.
[0040]
According to the present embodiment, even if an event that fluctuates the drive torque of the alternator, that is, an increase or decrease in the engine speed or the electric load occurs, the event can be dealt with without rapidly changing the drive torque of the alternator. become.
[0041]
In the present embodiment, an induction machine constituted by a rotor and a stator having a three-phase winding as a multi-phase winding has been described as an example. However, the present invention is not limited to this, and the present invention is not limited to this. The same can be applied to a case where other multi-phase windings are adopted.
[0042]
【The invention's effect】
As described above, according to the present invention, even if the electric load increases or decreases, power generation control without driving torque fluctuation is performed first, and thereafter, power generation control with driving torque fluctuation is performed gradually. In addition, even if the electric load increases or decreases, the ideal control of the amount of generated power can be performed without any fluctuation in the driving torque.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of a vehicle power generation device of the present invention.
FIG. 2 is a diagram showing a configuration of an alternator of the present invention.
FIG. 3 is a diagram for explaining a control method according to the first embodiment of the present invention.
FIG. 4 is a diagram showing a relationship between a relative speed N and a driving torque T using a temperature of an alternator as a parameter.
FIG. 5 is a diagram illustrating a control method according to a second embodiment of the present invention.
FIG. 6 is a diagram illustrating a control method according to a third embodiment of the present invention.
FIG. 7 is a diagram showing a relationship between a relative speed N of a rotating magnetic field and an efficiency η.
FIG. 8 is a flowchart illustrating a control method according to the first embodiment.
FIG. 9 is a diagram showing a configuration of a main part of a conventional alternator.
FIG. 10 is a diagram showing a relationship between a relative speed N and a driving torque T.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Alternator, 1R ... Rotor, 1S ... Stator, 2 ... Rotor excitation device, 3 ... ACG / ECU, 4 ... Engine ECU, 5 ... Switching control device, 7 ... Output control device, 8 ... Short circuit device, 9 ... Battery , 11, 12: three-phase field coil, 13: rotary shaft, 14: pulley, 15a: front bearing, 15b: rear bearing, 17: housing, 18a to 18c: slip ring, 19a to 19c: brush

Claims (2)

An induction machine including a rotor and a stator having multi-phase windings, the rotor being rotated by the rotation of the internal combustion engine being transmitted,
A battery charged by the induction machine;
A rotating magnetic field generating unit that is supplied with power from the battery and generates a rotating magnetic field in the multi-phase winding of the rotor,
The rotating magnetic field generating means, when the electric load increases or decreases, generates a rotating magnetic field speed so that the increased or decreased electric load can be covered without driving torque fluctuation, and then the increased or decreased electric load is applied to the stator. A power generation device for an internal combustion engine, which gradually executes a rotating magnetic field control with a drive torque fluctuation so that a relative speed of a rotating magnetic field can be satisfied even at a predetermined rotation speed. The power generator for an internal combustion engine according to claim 1 , wherein the increase or decrease of the electric load is an on / off operation of a headlight or an air conditioner.

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