JP2001069797A - Current-adjusting device of starter generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the current-adjusting device of a starter generator that suppresses heat generation on power generation for reducing the capacity of parts and the heat-resistance grade of a lead wire, and suppresses excessive charging for preventing the life of a battery from being decreased. SOLUTION: A system for controlling the starter generator in a small two- wheeled vehicle is composed of an ACG starter 3 with an armature coil 1 and a field coil 2, a motor driver and FET bridge circuit 4, an FET bridge driving logic circuit 5, a field coil control circuit 6, a current sensor 7 for monitoring the field current of the field coil 2, a current sensor 8 for monitoring an output current, and the like. The field coil control circuit 6 sets an upper limit value to the output current in operation as a generator based on the monitoring result of the current sensors 7 and 8. Also, when the current value of the output current is to exceed the upper limit value, the field coil control circuit 6 functions while a field current being energized to the field coil 2 is controlled so that the output current is within the upper limit value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting / generating machine such as an engine for a small motorcycle or a general-purpose engine, and is particularly effective when applied to a current adjusting system in a variable field type or hybrid field type starting generator. Technology.

[0002]

2. Description of the Related Art In general, in many small motorcycle engines, a starter motor for starting the engine and a generator for power generation driven by the engine are often mounted separately. However, despite the fact that the motor and the generator have the same basic configuration, the starter motor is used only at the time of starting, and the magnet generator is used after the starting. Therefore, conventionally, development of a starting generator in which a rotor and a stator of a generator are used also as a field element and an armature of a starter motor has been attempted.

In this case, a so-called outer rotor type in which a rotor having a permanent magnet is arranged outside a stator is widely known as a starting generator. When this starter generator is used as a starter motor,
The power from the power supply is supplied to the motor windings and the interaction between the magnetic field formed by the motor and the magnetic field from the permanent magnet of the rotor creates a rotational force, rotates the crankshaft, and starts the engine. Further, when the magnet is used as a magnet generator after the start of the engine, the magnetic flux of the permanent magnet of the rotor rotated by the crankshaft acts on the generator winding to generate an electromotive force.

[0004]

However, in the starting generator as described above, the magnetic circuit constants required for the starter motor and the generator, particularly the effective magnetic flux, are greatly different, so that both functions are used together. In this case, there is a potential design problem that matching is difficult. As a countermeasure against this, a so-called variable field type or hybrid field type start-up power generation that uses a permanent magnet and a field coil together and adjusts the field current according to the purpose so that the effective magnetic flux can be changed. Machine has already been proposed.

In this variable field or hybrid field starting generator, a plurality of permanent magnets magnetized to the same polarity and a magnetic material disposed between the permanent magnets are used as field means. A field element having a plurality of control poles, and a field coil forming a closed magnetic path passing through the control poles of the field element. It is possible to obtain the required generated current. For example, the charging characteristics of the charging current with respect to the rotation speed when the field current (IF) is varied are as shown in FIG.

[0006] However, when the battery is in an excessively discharged state or when the battery is degraded, for example, in an abnormal state, a charging current full of power generation capacity flows (an output over region in FIG. 4). Therefore, unless a rectifying element or a lead wire for power generation having a large capacity capable of flowing this current is selected, there is a risk of burning due to heat generation. On the other hand, since the battery can use only a current equal to or less than a certain value as stored energy, an excessively large charging current is converted into heat, which causes abnormal heating of the battery and leads to deterioration of the battery.

Therefore, an object of the present invention is to select the rectifying element and the lead wire as described above, and pay attention to the problem of abnormal heat generation of the battery. It is an object of the present invention to provide a current adjusting device of a starting generator that can be downgraded and can suppress excessive charging to prevent a reduction in battery life.

[0008]

The present invention is applied to a current adjusting device for a starting generator of a variable field type or a hybrid field type, and sets an upper limit value for an output current during operation as a generator. If the current value of the output current is about to exceed the upper limit, the control means controls the field current supplied to the field coil so that the output current falls within the upper limit.

Specifically, in order to set an upper limit value of the output current for each rotation speed and to limit the field current so that the output current does not exceed the upper limit value, the control means includes an output current output line. A current sensor for monitoring the output current. The output current monitored by the current sensor is set so as not to exceed a preset upper limit value of the output current set for each rotation speed. The PWM duty of the magnetic current is controlled.

In order to limit the field current so that the output current does not exceed the upper limit value, the control means is provided in a field current circuit, and monitors the field current. And a PW of the field current so that the field current monitored by the current sensor does not exceed a preset upper limit of the field current determined for each rotation speed.
To control the M duty, or to limit the upper limit of the PWM duty so as not to exceed the preset PWM duty of the field current corresponding to the upper limit of the field current determined for each rotation speed. It was done.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a functional configuration diagram showing a control system including a current adjusting device of a starting generator according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing charging characteristics in the present embodiment, and FIG. FIG.

First, an example of the configuration of a control system including a current adjusting device for a starting generator according to the present embodiment will be described with reference to FIG. The control system for a starting generator according to the present embodiment is configured to have both an engine starting device and a power generating device in a small motorcycle, for example, and is integrally combined with the engine. That is, the starting generator is configured to operate as a starter motor when the engine is started, and to operate as a generator after the engine is started.

As shown in FIG. 1, the control system of the starting generator includes, for example, an ACG starter 3 having an armature coil 1 and a field coil 2, an energization control of the ACG starter 3, and a rectification of a generated voltage. Driver & FET bridge circuit 4 that performs
An FET bridge drive logic circuit 5 for driving the ET bridge circuit 4; a field coil control circuit 6 for controlling energization of the field coil 2; a current sensor 7 for monitoring the field current of the field coil 2; Current sensor 8 for monitoring
Ignition unit 11 having PU 9 and ignition circuit 10
And an ignition coil 12 and a spark plug 13 for starting the engine, and a battery 1 charged during power generation.
4, a commutation position detecting pulsar & sensor 15, an ACG pulsar & sensor 16, and the like.

Although not shown, the ACG starter 3 is, for example, an outer rotor type brushless motor, and an armature coil 1 composed of a motor winding and a generator winding by Y connection is wound around a stator. A rotor is rotatably arranged around the periphery. The rotor is provided with a field element including a plurality of permanent magnets magnetized to the same polarity and a plurality of control poles made of a magnetic material between the permanent magnets. A magnetic flux which forms a closed magnetic path passing through the control pole of the field element and is combined with the magnetic flux by the permanent magnet is generated by the field coil 2. The rotor of the ACG starter 3 is directly connected to the crankshaft of the engine.

Motor driver & FET bridge circuit 4
Is connected to the ACG starter 3 and connected to the FET bridge drive logic circuit 5 and has functions of an energization control unit when the ACG starter 3 operates as a motor and a rectifying unit when the ACG starter 3 operates as a generator. ing. During operation as a motor, commutation control is performed by switching the current flowing in each of the U-phase, V-phase, and W-phase armature coils 1 by Y-connection of the armature coils 1 using an FET bridge circuit including a plurality of FETs. At the time of operation as a generator, the power generation voltage generated in the armature coil 1 is rectified by the FET bridge circuit to charge the battery 14.

The FET bridge drive logic circuit 5 is connected to the motor driver & FET bridge circuit 4 and connected to the CPU 9 of the ignition unit 11,
9 based on control signals such as motor operation ON / OFF, forward / reverse switching, rotation pulse, etc.
The bridge circuit 4 is configured to output a signal for driving the FET bridge circuit. A commutation position detection pulser & sensor 15 as position detection means is connected to the FET bridge drive logic circuit 5, and this sensor signal is used to control commutation of the armature coil 1.

The field coil control circuit 6 is connected to the field coil 2 of the ACG starter 3 via the current sensor 7 and is connected to the CPU 9 of the ignition unit 11,
It is configured to output a signal for controlling the energization of the field coil 2 based on the control signal from U9. Also,
Based on the field current detected by the current sensor 7, it is also possible to feedback control the energization of the field coil 2. In particular, the field coil control circuit 6 sets an upper limit value for the output current during operation as a generator, and when the current value of the output current is likely to exceed the upper limit value,
The field coil 2 is set so that the output current falls within this upper limit value.
It functions as a control means for controlling a field current supplied to the power supply.

The current sensor 7 for monitoring the field current has an AC
It is connected between the field coil 2 of the G starter 3 and the field coil control circuit 6 to detect a field current flowing through the field coil 2, and the detection result is fed back to the field coil control circuit 6. It is configured.

A current sensor 8 for monitoring the output current is connected between the motor driver & FET bridge circuit 4 and the battery 14, and a CPU 9 of the ignition unit 11
, And detects an output current flowing during operation as a generator, and the detection result is fed back to the field coil control circuit 6 via the CPU 9 of the ignition unit 11.

The ignition unit 11 includes a CPU 9 for controlling the entire system, an ignition circuit 10 for starting the engine, and the like. The CPU 9 is connected to the FET bridge drive logic circuit 5, the field coil control circuit 6, the current sensor 8, the ACG pulser & sensor 16, the internal ignition circuit 10, and the like. Control signals such as forward / reverse switching and rotation pulses are output to the field coil control circuit 6, and a feedback signal from the current sensor 8 and a signal from the ACG pulser & sensor 16 are input. The ignition circuit 10 includes the ignition coil 1
2. When the ignition switch is turned on when connected to the internal CPU 9 or the like, the ignition coil 12 and the spark plug 13 connected to the ignition coil 12
It is configured to start the engine via such as.

Next, the operation of this embodiment will be described with reference to FIG.
2 and 3, the operation at the time of motor operation to operate as a starter motor and the operation at the time of power generation operation to operate as a generator will be described. FIG. 2 shows the relationship between the number of revolutions and the charging current when the field current (IF) is varied as charging characteristics. FIG. 3 is a circuit diagram and a waveform diagram for explaining the PWM control.

First, when the engine is started, when the motor is operated as a starter motor, the armature coil 1 (functioning as a motor winding) of the ACG starter 3 corresponds to a drive signal from the motor driver & FET bridge circuit 4. A phase voltage is applied. At the same time, a field current is supplied to the field coil 2 from the field coil control circuit 6. The rotor is rotated by the interaction between the rotating magnetic field formed by energizing the armature coil 1, the magnetic field generated by the permanent magnet of the rotor, and the magnetic field generated by the control pole formed by energizing the field coil 2. . The position of the rotating rotor is momentarily measured by detecting the position by the pulsar & sensor 15 for detecting the commutation position. Then, this measurement information is transmitted to the FET bridge drive logic circuit 5.
And the motor driver & FET bridge circuit 4 rotates the rotor continuously and stably.

Further, when the engine is started, the FET bridge drive logic circuit 5 automatically stops transmitting the drive signal based on the detection signal from the commutation position detection pulser & sensor 15, and the motor generates the generator. Switch to
Then, at the time of the power generation operation for operating as a generator, the rotor connected to the crankshaft rotates around the stator. For this reason, the magnetic flux of the permanent magnet of the rotor and the magnetic flux of the control pole formed by energizing the field coil 2 form a rotating magnetic field and turn off the armature coil 1 (functioning as a generator winding). , An electromotive force is generated in the armature coil 1. The electromotive force of the armature coil 1 is rectified via the motor driver & FET bridge circuit 4 and charged to the battery 14 or taken out to be supplied to a desired load.

In particular, during operation as the generator, the field coil control circuit 6 sets an upper limit value for the output current. If the current value of the output current is about to exceed the upper limit value, the upper limit value is set. The field current supplied to the field coil 2 is controlled so that the output current falls within the range. In controlling the field current, it is better to set the upper limit of the output current for each rotation speed, and to set the upper limit as the rotation speed increases. In addition, an upper limit value is set according to the cooling state (high rotation speed → high speed → high cooling capacity). This control method includes, for example, an output current direct detection feedback control method, a field current detection feedback control method, and an open loop control method, which will be described below in order.

Output Current Direct Detection Feedback Control System In this control system, the output current monitored by the output current monitoring current sensor 8 is controlled by the output current upper limit value (a data map or a calculation formula) determined for each rotation speed. This is a method of controlling the PWM duty of the field current so as not to exceed (set in advance).

According to this control method, the output current is monitored by the current sensor 8 provided on the output line of the output current, so that the output current does not exceed the upper limit value. The PWM duty of the current can be controlled. Therefore, as shown in FIG. 2, the field current flowing through the field coil 2 (IF = + X, 0, -X, -XX [A]; X
(Arbitrary number) can be controlled such that the charging current does not exceed the upper limit value in accordance with the rotation speed.

Field current detection feedback control system In this control system, the current sensor 7 for monitoring the field current is used to limit the field current so that the output current does not exceed the upper limit value. Is a method of controlling the PWM duty of the field current so that the field current monitored by the above does not exceed the upper limit value of the field current (set in advance by a data map or a calculation formula) determined for each rotation speed. .

According to this control method, the field current is monitored by the current sensor 7 provided in the circuit for the field current.
The PWM duty of the field current flowing through the field coil 2 can be controlled so that the field current does not exceed the upper limit. Therefore, similarly to the output current direct detection feedback control method, the charging current when the field current flowing through the field coil 2 is changed can be controlled so as not to exceed the upper limit value in accordance with the rotation speed. .

Open-loop control system This control system is designed so that the PWM duty of the field current corresponding to the upper limit value of the field current determined for each rotation speed (preset by a data map or a calculation formula) is not exceeded. P
This is a method for limiting the upper limit of the WM duty.

According to this control method, the PW is controlled so as not to exceed the PWM duty of the field current flowing through the field coil 2.
The upper limit of M duty can be limited. Therefore,
Similar to the output current direct detection feedback control method, the charging current when the field current flowing through the field coil 2 is varied can be controlled so as not to exceed the upper limit value in accordance with the rotation speed.

Here, the relationship between the output current, the number of revolutions, the field current, the PWM duty, and the like in each of the above control methods will be described. Generally, in estimating the amount of power generated by a motor, the voltage generated by the motor is determined by the rotation speed and the back electromotive constant Ke, as in (Equation 1). In a normal PM motor, the back electromotive constant Ke is basically constant. Therefore, if the rotation speed is monitored, the amount of power generation can be estimated.

Generated voltage = Ke × rotation speed (Equation 1) For example, in the case of a three-phase brushless motor as in this embodiment, the rotation speed is estimated using the commutation position detection pulser & sensor 15. be able to. In the case of DSG, the back electromotive force constant (torque constant) is variable by the field current. The relationship between the field current and the back electromotive constant can be dealt with by grasping in advance and having the map or function in the CPU 9. Therefore, if the field current during operation can be estimated, the amount of power generation can be grasped.

In estimating the field current, when the power supply voltage is VB, the apparent voltage applied to the field coil 2 at the time of PWM control is V ', and the PWM duty is D.
If it is uty, it can be expressed as (Equation 2).

V ′ = VB × Duty (Equation 2) Here, assuming that the resistance value of the field coil 2 is R, the current I flowing through the field coil 2 is I = V ′ / R = (VB × Duty) / R (Equation 3) Therefore, if the resistance value of the field coil 2 is known, the PWM duty for flowing a predetermined current can be calculated by monitoring the power supply voltage, and the field current can be controlled by outputting the duty. Becomes However, the variation in the resistance value of the field coil 2 and the amount of temperature change must be recognized as an error. In addition, since there is a time lag from the application of the duty by the time constant of the field coil 2 to the predetermined current, it is necessary to pay attention to the control cycle so as not to cause oscillation.

Next, the PWM control will be described. P
The WM control circuit can be shown, for example, as shown in FIG. This PWM control circuit is configured by connecting the field coil 2 of the ACG starter 3 and the FET of the field coil control circuit 6. That is, one of the field coils 2 is connected to the power supply voltage, the other is connected to the drain of the FET, and the source of the FET is connected to the ground voltage. Further, a diode is connected to both ends of the field coil 2 in anti-parallel, and a diode is connected between the drain and the source of the FET.

In FIG. 3A, when the FET is on, a current flows through the FET connected in series via the field coil 2, and when the FET is off, a diode connected in anti-parallel via the field coil 2 The current flows through. The reason why the brushless motor or the PWM control of the field coil 2 can be performed is that the loop current flows through the diode due to the inductance energy during the off period of the FET. Therefore, when an FET is used for the field coil control circuit 6,
Since a diode is formed due to its structure (parasitic diode), this is actively used. A requirement for the diode used here is a diode having a short reverse recovery time. If this is long, a short-circuit current flows at the moment when the FET is turned on, and the element is destroyed.

FIGS. 3 (b) and 3 (c) show waveforms obtained by performing a simulation with this circuit. FIG. 3 (b) shows the current of the FET and the diode, and FIG. 3 (c) shows the current of the field coil 2. Indicates the field current. Although the currents of the FET and the diode are rectangular waves, the field currents are the sum of these and have a smooth waveform. The duty in the PWM control can be expressed as (Equation 4).

PWM duty = a / (a + b) (Equation 4) In relation to the output current, the rotation speed, the field current, the PWM duty and the like as described above, these are set in advance by a data map or a calculation formula. The upper limit is set for the output current during operation as a generator, and if the current value of this output current is likely to exceed the upper limit, the output current is set to fall within this upper limit. The field current applied to the magnetic coil 2 can be controlled.

Therefore, according to the control system including the current adjusting device of the starting generator according to the present embodiment, the heat generation of the field coil 2 and the diode at the time of power generation can be suppressed, and the possibility of burning due to the heat generation can be prevented. When selecting parts, it is possible to select one having a small capacity, and it is also possible to reduce the heat-resistant grade of the lead wire. In addition, since excessive charging of the battery 14 during power generation is suppressed and abnormal heat generation can be prevented, the life of the battery 14 can be prevented from being shortened.

The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the scope of the invention. For example, in the above-described embodiment, the starting generator of a small motorcycle has been described as an example. However, the present invention is not limited to this. For example, a variable field type or a hybrid It can be widely applied to magnetic starting generators in general.

[0041]

As described above, according to the current adjusting device of the starting generator of the present invention, when operating as a generator,
When an upper limit value is set for the output current and the current value of this output current is about to exceed the upper limit value, control is performed to control the field current that flows through the field coil so that the output current falls within this upper limit value. By having the means, heat generation of the coil and the diode during power generation can be suppressed, so that the capacity can be reduced and the heat-resistant grade of the lead wire can be reduced. As a result, the size and cost of the current adjusting device of the starting generator can be reduced.

Further, since excessive charging of the battery during power generation can be suppressed, it is possible to prevent a reduction in the life of the battery.

Further, a current sensor for monitoring the field current is provided, and the monitored field current does not exceed the upper limit value of the field current determined for each rotation speed so that the PWM of the field current does not exceed the upper limit value.
By controlling the duty, the field current and rotation speed,
By estimating the charging current from the power supply voltage, current adjustment can be performed without a current sensor that monitors the output current.

Also, by limiting the upper limit of the PWM duty so as not to exceed the PWM duty of the field current corresponding to the upper limit of the field current determined for each rotation speed,
By estimating the field current from the power supply voltage, the PWM duty, and the coil resistance, current adjustment can be performed without a current sensor for monitoring the field current and a current sensor for monitoring the output current.

[Brief description of the drawings]

FIG. 1 is a functional configuration diagram showing a control system including a current adjusting device of a starting generator according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing charging characteristics in one embodiment of the present invention.

FIGS. 3 (a), (b), and (c) are a circuit diagram and a waveform diagram for explaining PWM control in an embodiment of the present invention.

FIG. 4 is a characteristic diagram showing charging characteristics in a control system of a starting generator which is a premise of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Armature coil 2 Field coil 3 ACG starter 4 Motor driver & FET bridge circuit 5 FET bridge drive logic circuit 6 Field coil control circuit 7 Current sensor 8 Current sensor 9 CPU 10 Ignition circuit 11 Ignition unit 12 Ignition coil 13 Spark plug 14 Battery 15 Commutation position detection pulser & sensor 16 ACG pulser & sensor

Continued on front page F term (reference) 5H590 AA01 AB02 AB04 BB04 CA23 CC12 CC18 CC24 CC29 CD01 CD03 CE05 DD25 DD64 DD72 EA02 EA10 EA15 EB02 FA06 FB03 FC14 GA02 GA04 GB05 HA02 HA04 HB03 HB06 JA02 JB02 KK06

Claims (4)

[Claims] 1. A stator on which an armature coil is wound, a rotor directly connected to a crankshaft of an engine and rotatably disposed around the stator, and detecting a position of the rotor. Position detection means, energization control means for energizing the armature coil with a current that forms a rotating magnetic field based on the detection result, rectification means for rectifying a generated voltage generated in the armature coil, A field element provided with a plurality of permanent magnets magnetized to the same pole, and a plurality of control poles made of a magnetic material disposed between the permanent magnets; and a control of the field element. A field coil forming a closed magnetic path passing through the poles, the starting generator operates as a motor when the engine is started, and operates as a generator after the starting. Set the value, When the current value of the output current is about to exceed the upper limit value, a control means is provided for controlling a field current supplied to the field coil so that the output current falls within the upper limit value. Starting generator current regulator. 2. The current adjusting device for a starting generator according to claim 1, wherein the control means includes a current sensor provided on an output line of the output current and monitoring the output current.
The PWM duty of the field current is controlled so that the output current monitored by the current sensor does not exceed a preset upper limit value of the output current determined for each rotation speed. Starting generator current regulator. 3. The current adjusting device for a starting generator according to claim 1, wherein said control means includes a current sensor provided in a circuit of said field current and monitoring the field current. Starting the motor so that the field current monitored in the step (c) does not exceed a preset upper limit value of the field current determined for each rotation speed. Generator current regulator. 4. The current adjusting device for a starting generator according to claim 1, wherein said control means controls a field current corresponding to a preset upper limit value of the field current determined for each rotation speed. A current adjusting device for a starting generator, wherein an upper limit of the PWM duty is limited so as not to exceed the PWM duty.