JPH0412640A - Controller and control method for generation on vehicle - Google Patents

Abstract

PURPOSE:To stabilize voltage control properties by providing the voltage feedback loop of an AC generator for battery charge with a compensating circuit. CONSTITUTION:The output voltage of an AC generator 1 for battery 3 charge is controlled so that the deviation between the set voltage value VBC and the feedback value of battery voltage VB may be zero even in the case where a load 11 current has changed sharply, so the voltage fluctuation width can be controlled small. Moreover, even in the case that the power supply wiring becomes long, and that the voltage drops greatly, it is controlled so that the voltage deviation may be zero, so output fluctuation width can be controlled without being affected by wiring. Moreover, even in the transient properties that the load 11 added to generator output changes suddenly, the output voltage can be controlled stably by a compensating circuit 13.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a generator control device and method thereof, and in particular, suitable characteristics can be obtained when applied to output voltage control of an automobile charging generator. The present invention relates to a control device for an automobile charging generator and a control method thereof.

[Conventional technology]

In conventional generator control devices and control methods, as shown in Japanese Patent Laid-Open No. 62-160043, the output voltage decreases depending on the load current of the generator. Furthermore, the output voltage waveform of the generator has large ripples, as shown in Utility Model Application No. 1-113587. Therefore, JP-A No. 61-262039,
As shown in Japanese Unexamined Patent Publication No. 60-35926, a filter (such as C-R) is used to detect battery voltage.

A specific example of the conventional example is shown in FIG. In Figure 2, 1 is a three-phase alternator, 2 is a three-phase rectifier that rectifies the output of the alternator 1 and supplies charging current to the battery 3, and 4 is the field winding of the alternator. Turn on the current flowing through the wire, 5 is the flywheel diode, and 6 is the field winding of 4.

A switching element (chopper) such as a power MOSFET for OFF control, 7 a voltage comparison comparator, 8 a C-
This is a low-pass filter composed of R and the like.

In the conventional system, the operation of the charging generator using the regulator is shown below. The output voltage of the alternator 1 is changed to the three-phase rectifier 2.
The current is rectified by the voltage V, and a charging current flows to the battery 3, and a feedback voltage Va is output. Then, the comparator 7 compares the internal set reference voltage VaC and the feedback voltage Vss passed through the low-pass filter, and if VBs is lower than Vac, the output of the comparator 7 becomes 11 HPj, turning on the chopper 6 and turning on the field winding. A current is passed through the wire 4 to increase the output voltage of the generator 1, and Va
becomes higher. Next, due to the rise in Va, the comparator 7 compares the set voltage VaC with a constant value, and outputs “L”.
A flywheel current is applied to the 0FFL field winding 4 of the chopper 6 serving as TT via a flywheel diode to attenuate it. These operations are repeated to control the battery voltage VB (generator output voltage) to be constant. The AC output of the three-phase generator is rectified into three phases by the rectifier 2 to obtain an output voltage of Va, but since it is a pulsating voltage that includes three-phase ripples, it is difficult to use the generator when a large current is flowing through the battery and load. When the output is increased, the rip voltage increases due to the influence of wiring resistance, etc. Therefore, ON/OFF control is generally performed in which a low-pass filter is used to smooth out the pulsation, and then a voltage comparator 7 is used for comparison.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, the rotational speed of the generator is synchronized with the car engine rotational speed, and the rotational speed of the generator is changed from an idling state to several tens of thousands of rpm.
The alternating current ripple frequency of the generator changes significantly. Further, there is a problem that the generator output voltage also changes significantly depending on the rotation speed.

Furthermore, if the load current is increased, the ripple in the generator output voltage will also increase due to the influence of wiring resistance.
There are problems such as poor output voltage control characteristics. Also, O
Due to the N/OFF control, the switching frequency changes due to the difference in the length of the wiring, and there is a problem that the switching frequency drops extremely to several Hz.

In addition, when PWM type current control is used in the minor loop to control the maximum value of the field current, the voltage control loop becomes unstable because a low-pass filter is used to remove ripples in the generator voltage. There were other problems.

An object of the present invention is to provide a charging power generator for automobiles that can reduce the output voltage fluctuation range without being affected by wiring resistance, etc. even when a large output current of the generator is passed, and can obtain good load fluctuation characteristics. To provide machine control equipment.

Another object of the present invention is to provide a charging generator control device that can control the output voltage of a charging generator without being affected by output voltage ripples of the generator. Another object of the present invention is to use a compensation circuit for stabilizing the control of a generator control device and a filter circuit for removing ripples in the output voltage of the generator in common without having to provide each independently, thereby eliminating the need for a filter circuit.

Another object of the present invention is to provide a control device for a charging generator for an automobile, which allows a voltage control system to operate stably without being affected by the length of power supply wiring, etc.

Another object of the present invention is to improve the control performance of an automobile when a digital control method is used, even when an inexpensive A/D converter with a small number of bits is used for signal input. To provide a control device for a charging generator.

[Means to solve the problem]

In order to achieve the above objective, a compensation circuit is added to the voltage feedback loop of the battery charging alternator, making it possible to stabilize the voltage control characteristics even when the rotational speed of the generator changes significantly. be. Furthermore, the compensation circuit can also absorb alternating current ripples in the generator voltage, so that the control stabilization compensation function and the filter function for removing ripples are shared. In addition, when a current control circuit is provided in the minor loop of the voltage control system of the charging alternator, a second compensation circuit that compensates for the current control system and a first compensation circuit that compensates for the voltage control system are provided. That's true. Further, in the charging generator control device, the compensation constant of the voltage control circuit is selected to be larger than the compensation constant of the current control circuit of the minor loop.

Further, the compensation constant is set to be larger than the field winding circuit constant of the charging generator.

[Effect]

According to the present invention configured as described above, the output voltage of the battery charging alternator has a deviation of 0 between the set voltage value and the battery voltage feedback value even when the load current changes significantly. Therefore, the voltage fluctuation range can be controlled to be small. In addition, even if the power supply wiring is long (and a large voltage drop occurs), the voltage deviation is controlled to be O, so the output voltage fluctuation range can be controlled to be small without being affected by the wiring. Even in transient characteristics where the load applied to the generator output changes suddenly, it is possible to stably control the output voltage using the compensation circuit.

Further, even when PWM control is performed, by using a compensation circuit, voltage control can be performed based on the PWM control circuit frequency without the PWM frequency changing due to the influence of power supply wiring.

Furthermore, by using a compensation circuit, the battery voltage (
It is possible to perform voltage feedback control without separately providing an AC ripple removal filter for the AC generator output.

Furthermore, since the charging alternator is directly connected to the automobile engine (or attached to a belt) and rotates, the number of revolutions of the generator changes significantly, and as a result, the rip frequency also changes significantly. Even in that case, the compensation circuit can remove voltage ripples and stabilize voltage control.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
In the figure, 1 is a three-phase alternating current generator, 2 is a three-phase rectifier that rectifies the output voltage of the generator 1 and supplies charging current to the battery 3, and 4 is the field winding of the alternator. , 5 is a flywheel diode, 6 is a switching element (chopper) such as a power MOSFET that controls ON/OFF of the current flowing in the field winding 4, and 9 is a switching element (chopper) such as a power MOSFET that controls the current flowing through the field winding 4. Also, 9 connects the generator 1 to the belt 1
0 is a prime mover such as an engine driven through 0, 11 is a lamp or other automotive load, 12 is a load 11 ON, , OF
13 is a compensation circuit including a deviation amplifier 131, and 14 is a PWM circuit, and the above-mentioned circuit constitutes an automobile charging generator control device.

The automobile generator 1 is driven by an automobile engine 9 and outputs three-phase alternating current voltage. This AC voltage is rectified by a three-phase rectifier 2 and supplies current to the battery 3. A plurality of loads 11 are connected to the battery 3 via switches 12. Loads include car air conditioners, lighting equipment,
These include fuel control electronic devices, audio equipment, etc. The output voltage of the generator 1 is determined by turning on the current flowing through the field winding using the chopper 6.

It changes by OFF control. That is, by controlling the current flowing through this field winding, the output voltage (current) of the generator is controlled so that the voltage of the battery 3 becomes a predetermined value. Further, the feedback control operation is as follows. The battery voltage Va is compared with the battery set voltage Vsc by a deviation amplifier 131, and the deviation E is outputted as a signal ε which has been multiplied by the compensation circuit 13. P.W.
The M circuit 14 outputs a duty corresponding to ε, drives the chopper 6, and turns on the voltage applied to the field winding 4.

OFF control.

Next, details of the compensation circuit will be explained.

An embodiment of the compensation circuit is shown in FIGS. 3(a) and 3(b).

FIG. 3(a) shows a proportional compensation system, in which the operational amplifier 132
and input resistance 133, 134, feedback resistance 135
, 136, the battery voltage VBs (voltage obtained by dividing the battery terminal voltage Va) and the battery set voltage Va
The output voltage ε can be obtained by multiplying the deviation from c by and recane. FIG. 3(b) shows a proportional/integral compensation system, which has integral compensation capacitors 137, 138 in series with feedback resistors 135, 136, and also has filter characteristics to reduce ripple voltage in the high frequency region.

FIG. 3(C) shows an integral compensation method, and since the feedback circuit is only capacitors 137 and 138, the input signal V
It operates until the deviation between BS and VBC becomes 0. Performs a so-called integral operation. At the same time, ripple voltage in the high frequency region can be reduced. That is, in addition to stabilizing and compensating the control of the charging generator, it also has a filter effect that can absorb the alternating current ripple voltage of the generator included in the battery voltage detection signal Vac.

FIGS. 4(a)-(c) are modifications of the compensation circuit shown in FIGS. 3(a)-(c). That is, in Figure 4,
The battery set voltage VaC is a constant DC voltage that does not include an AC ripple voltage, unlike the output voltage Vas of the generator. Therefore, even if the resistor and capacitor of the ten-terminal input section of the operational amplifier 132 are omitted, the above-mentioned function can be realized.

FIG. 5 shows a block diagram of an example of another embodiment. In FIG. 5, which shows a case where a current control function is added to the minor loop of the voltage control system for a battery charging generator, explanations of the configurations with the same symbols as shown in FIG. 1 will be omitted. In FIG. 5, A is a voltage control circuit, which is composed of a deviation amplifier 131 and a first compensation circuit 13, similar to that shown in FIG. Further, B is a newly configured current control circuit, which includes a second deviation amplifier 151 and a second compensation circuit 15. , a PWM circuit 14, a current detection circuit 16 that detects the current of the chopper 6 via a detection resistor 17, and the like.

Control of field winding current will be explained below.

The terminal voltage Va of the battery is compared with the battery set voltage Vac, and the deviation ε is amplified by the first compensation circuit, and the high frequency component is cut off, thereby outputting a signal of K□ε1. That is, the field current command value l1c=Kiε is obtained.

In the current control circuit B, the second deviation amplifier 151 compares the field current command value Iic and the current detection signal Izz of the field current detection circuit, and the deviation ε2 is calculated by the second compensation circuit 1.
5, high frequency components are cut, and a signal of K2ε2 is output.

In the PWM circuit 14, the current deviation signal (including amplification) Kz
Decide the duty according to ε2 and turn on chopper 6
, to control the current flowing through the field winding 4.

Then, the field current that actually flows is fed back to the deviation amplifier 151 via the detection resistor 17 and the current detection signal 16, and current feedback control is performed. The second compensation circuit constant in current control in that case is as follows.

The field winding 4 of the charging generator generally has a large number of turns, so it has a large inductance and a long time constant. Therefore, in order to speed up the response of the current control system, it is necessary to perform optimal compensation using the above-described compensation methods such as proportional, proportional/integral, and integral.

On the other hand, the winding time constant of the armature 1 is smaller than the time constant of the field winding. Therefore, when performing compensation with the first compensation circuit of the voltage control system, it is necessary to make the compensation constant larger than the control response of the B current control circuit. That is, unless voltage control system response time>current control system response time is satisfied, control of the charging generator will not be stable. This is because the battery voltage VB, which is the feedback signal of the voltage control system, has
A three-phase generator contains a lot of ripple, and the first compensation constant is set to the field current in order to remove the ripple and also to eliminate the effects of wiring resistance and inductance when the battery wiring becomes long. It is necessary to make it sufficiently longer than the control system. As a result, it is possible to operate the voltage control system stably.

Next, a concrete detailed circuit of FIG. 5 is shown in FIG. 6th
In the figure, 13 includes a first compensation circuit and constitutes a voltage control system. Specifically, operational amplifier (deviation amplifier)
132. An integrator is configured with an input resistor (integrating resistor) 133 and a feedback capacitor 137 (integrating capacitor), and the battery voltage VB is connected to voltage dividing resistors 191 and 19.
It also has a filter function to remove the riffle of the voltage VBS divided by 2. It also outputs the deviation between the battery detection voltage VaS and the battery set voltage Vac.

15 is a second compensation circuit, which includes a deviation amplifier 152 and input resistors 153, 154 . Feedback resistance 155.1
56 constitutes a proportional compensation circuit, and together they constitute a current control system.

14 is a PWM circuit, 141 is an operational amplifier, and input resistors 142, 143, 144 and a feedback capacitor 145 constitute an integrator, and the outputs of amplifiers 146 and 146 are positively fed back by a resistor 147, and an input resistor 148 However,
The comparator is operated as a comparator with hysteresis, and the operating level of the comparator in this case is determined by Vc set via the input resistor 149. By feeding back the output Co of the comparator to the integral input resistor 142, a PWM control circuit capable of duty control is obtained. Above, PWM
The control circuit 14 has a function of proportionally controlling the duty (conduction rate) of the output signal eo with respect to the hexagonal signal (voltage) εI.

18 is a gate drive circuit for the chopper 6, which amplifies the PWM signal eo and generates a signal for driving the gate. Further, the gate drive circuit 18 has a function of boosting the voltage in addition to amplifying the drive signal.

16 is a current detection circuit, which includes an operational amplifier 161°, input resistors 162, 163 . It is composed of feedback resistors 164 and 165.

Reference numeral 17 is a current detection resistor that detects the current flowing through the chopper 6. Chopper 6 is a power MO
A case is shown in which a 5FET is used, and a part of the element current is shunted and passed through the current detection resistor 17 to be detected by voltage.

The figure shows the case of a so-called high-side switch where the switch is on the positive power supply side, but it has the same function even if the switch is used on the negative side opposite to the load. good.

Next, the operation of FIG. 6 will be explained. First, the operation of the voltage control circuit 13 is as follows. The voltage control circuit 13 performs feedback control so that the voltage Vss obtained by dividing the battery voltage Va matches the battery voltage setting value VBC. That is, the deviation signal I (C (current command value)) is output until the deviation between the battery voltage Vas and the set value VaC becomes completely ON, and is given to the current control circuit 15.

In the current control circuit, the field current command ■work. is given, the deviation amplifier 152 generates a current feedback signal 111
A signal ε2 is generated by amplifying the deviation signal obtained from
Give it to the PWM circuit.

In the PWM circuit, the PWM signal e is generated according to the signal ε2.
The field current I is controlled by changing the duty of o and operating the chopper 6 via the gate drive circuit 18. To directly detect the field current, it is possible to use an insulated current detector, a shunt resistor, etc.; An example is shown in which a method of detecting a part of the current is detected. The power element current signal detected by the detection resistor 17 is amplified by the current detection circuit 16, becomes an IIK signal, and feedback control is performed so that it matches the current command value IZC.

Figure 7 shows a detailed configuration diagram of the alternator.

1 is an alternator, and has an armature winding 10. Field winding 4.
Consists of three-phase rectifier 2, etc. When the rotor around which the field winding 4 is wound is rotated by a driving device such as an engine, three-phase alternating current voltage is generated from the ten armature windings. After converting alternating current into direct current voltage including pulsating voltage with this three-phase rectifier, charging current to battery 3 and load 11 (switch turned off)
(N time)).

In the above operation, the alternating current output voltage can be varied by controlling the current flowing through the field winding 4 to turn on and off using the chopper 6. That is, when the chopper 6 is turned on, the battery voltage Va passes through the chopper 6 and the field current Ii flows to the field winding 4.

Next, when the chopper 6 is turned off, the current flowing through the field winding 4 tries to continue flowing, and becomes a flywheel current through the diode 5, resulting in a pulsating current that attenuates.

Therefore, by changing the conduction rate (ON10N+0FF) of the chopper 6, the field current can be controlled.

Note that when the inductance of the field winding is large, the pulsating portion of the field current Ii is small and becomes a current close to a direct current.

Returning to FIG. 6, in the control system of the charging generator shown in the figure, the following method is used as described above in order to stabilize the output voltage control of the charging generator. That is,
In order to speed up the current control response operation, the second compensation circuit 1
5 (current control circuit) is provided with only proportional compensation. Also,
In order to operate the voltage control of the charging generator stably, the first
The compensation circuit (voltage control circuit) of
The value is set to a value that is sufficiently larger than the compensation circuit time constant.

That is, by making the second compensation circuit constant sufficiently large, the three-phase rectification ripple included in the battery voltage Va can be removed, and the operation of the voltage control system can be stabilized.

Further, other embodiments are shown in FIG.

This example shows a case where a microcomputer is used to control a charging generator.The voltage control system (voltage deviation) is performed using the analog control described above, and PWM control, current control, etc. are performed using a microcomputer and software processing. We have shown cases in which this is done. In FIG. 8, 13 is a voltage control circuit, 19 is a microcomputer, 191
is an A/D converter, 192 is a D/A converter, 193 is cp
u, 194 is a PWM generation circuit. Voltage control circuit 13
Then, the battery voltage signal Vas and the battery voltage setting value V
Outputs the deviation fC of ac. ①Engineer C outputs the battery signal VSS of the feedback signal until it matches the set value, and controls the field current of the generator described above.

The set voltage Vac is determined by inputting the data set in the memory in the CPU 93 to the deviation amplifier 13 via the D/A converter.
Give to 2. The deviation signal IfC is input to the CPU 193 via the A/D 191. For voltage control only,
The PWM duty according to the deviation signal It is 193 C.
It is calculated by the PU, and the PWM power is calculated via the PWM circuit 194.
Output o.

In addition, when performing current control, although not shown, A
/D converter to take in the feedback current, 19
3 CPU performs current control calculations using software, PWM
A PWM output signal eo is output via the circuit 194.

In the above method, the deviation compensation calculation between the battery voltage of the feedback signal and the set voltage is performed in an analog manner, so that the resolution of voltage detection can be improved. For example, in the case of an all-digital system, when the battery voltage is input through an A/D converter and amplification calculations are performed in the voltage control section, the bit resolution deteriorates, resulting in poor control accuracy. Therefore, in order to improve voltage control performance, a high-precision A/D
A converter is required. On the other hand, in the case of the present invention, since A/D conversion is performed after operational amplification, the number of bits required for PWM duty setting is sufficient, so there is no need for a high-precision A/D converter.

As described above, by using the single-vehicle power type analog and digital systems, highly accurate control characteristics of the generator can be obtained.

An example of the voltage fluctuation characteristics of the charging generator to which the present invention described above is applied is shown in FIG. 9 in comparison with the conventional system. The battery voltage fluctuation characteristics are shown when the current flowing from the generator output to the load is changed by about 0 to 100 A.

As for the voltage control characteristics, while the conventional method fluctuates significantly, the battery voltage fluctuates little when the present invention is applied, and exhibits good characteristics with almost no change.

As described above, according to the embodiments of the present invention, the output control characteristics of the charging generator for automobiles are such that the output voltage can be kept constant even when the generator's load fluctuates or the rotational speed changes. This has the effect of improving the performance of the machine.

〔Effect of the invention〕

As explained above, according to the present invention, in the output voltage control of the charging generator, by providing a compensation circuit in the feedback loop, even when the load of the charging generator output suddenly changes or when a large capacity load is added, This has the effect of controlling the voltage to a constant level. Furthermore, by using Pt11M control to control the field current of the charging generator, the chopping frequency of the field current can be defined, which simplifies the control method and improves the control characteristics. Furthermore, the use of the voltage stabilization compensation circuit has the effect of eliminating the need for a filter for removing ripples in the generator output voltage.

In addition, integral compensation or proportional compensation can be used for output voltage stabilization compensation.
By using integral compensation, it is possible to control the output voltage of the generator with high precision, and it is also possible to eliminate voltage fluctuations due to the influence of wiring resistance when the power supply wiring becomes long. Furthermore, by adding a current control system to the minor loop of the voltage control system and optimizing each compensation constant,
In addition to stabilizing voltage control, this has the effect of making it possible to vary any field current. Furthermore, in a charging generator for an automobile, by performing analog compensation for the voltage control system and performing other controls digitally, better control performance can be obtained than in the case of all-digital control.

[Brief explanation of the drawing]

Claims (1)

[Scope of Claims] 1. A charging generator control device for an automobile battery charging generator, characterized in that a compensation circuit for voltage stabilization is provided in a voltage feedback loop for controlling the output voltage of the generator. 2. The charging generator control device according to item 1, characterized in that a PWM control means is provided for controlling the field current of the charging generator. 3. The charging generator control device according to item 1, wherein the voltage stabilization compensation circuit is also used as a ripple filter circuit for the battery. 4. In the first term above, the voltage stabilization compensation circuit has a proportional
A charging generator control device characterized by performing integral compensation. 5. In the above item 1, as the voltage stabilization compensation means,
A charging generator control device characterized by performing integral compensation. 6. In the above item 2, a current control circuit is provided in the minor loop of the voltage control circuit, and the current control circuit includes a PWM
1. A charging generator control device comprising a control circuit, controlling by feedback of field current, and performing voltage stabilization compensation and current stabilization compensation in each of the voltage and current control circuits. 7. The charging generator control device according to item 6, characterized in that the stabilization compensation constant of the voltage control circuit is larger than the stabilization compensation constant of the current control circuit. 8. The charging generator control device according to item 2, wherein the voltage stabilization compensation is performed by an analog method, and other control calculations are performed by a digital method.