JPH061957B2 - Control system for engine driven generator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control system for an engine-driven generator that controls switching of a generated voltage of a generator driven by an engine.

2. Description of the Related Art Generally, as shown in FIG.
The battery 1 and the generator 3 driven by the engine 2 are connected in parallel to the electric load 4, and the generated voltage of the generator 3 can sufficiently supply the battery 1 with charge and the capacity of the electric load 4. It is usual that the battery 1 is regulated to a predetermined voltage (for example, 14.5 V) so that Then, the power generated by the generator 3 changes according to the usage state of the electric load, and the load on the engine 2 that drives the generator 3 also changes in proportion to it, but the capacity of the electric load 4 is small and the engine load is small. When 2 is in an operating state other than deceleration, the power generation voltage of the generator 3 is lowered to the charging voltage of the battery 1 (for example, 12.5V) and the engine 2 of the generator 3 is reduced.
The load on the engine can be reduced, and by doing so, the load on the generator 3 can be eliminated, and the drive loss of the engine 2 can be reduced accordingly, and the fuel consumption can be improved.

FIG. 3 shows the characteristics of the output current of the generator with respect to the engine speed when the generated voltage is used as a parameter.
When the power generation voltage increases, the power generation amount increases, and the battery charging speed increases. By using this characteristic, if the power generation is performed at a lower voltage during a light electric load that is a normal state, the charging current is reduced and the engine load is lightened so that the engine load can be reduced. Become. Further, when the electric load becomes heavy, it is possible to sufficiently meet the load demand and suppress the discharge of the battery by switching the generated voltage to a higher value to increase the amount of power generation.

Therefore, conventionally, a battery and a generator driven by an engine are connected in parallel to an electric load in a circuit configuration, and depending on the charging state of the battery, the turning-on state of the electric load, and the operating state of the engine. In order to keep the battery voltage constant at all times, the voltage regulator reference that detects the battery voltage and compares it with a preset reference voltage, and controls the generator field current to turn on and off according to the comparison result. The generation voltage is increased and the switching control is made to be low.

However, in the control of such a conventional engine-driven generator, when the generator is switched to the small power generation side with a lower power generation amount, electric power with a large inrush current when the power is turned on, such as a headlight and an air conditioner, is generated. When the generator is switched to the large power generation side with a higher power generation amount when the load is turned on, the ion concentration in the battery electrolyte based on the difference in the reference generation voltage at the initial stage of the switching changes the winding at a high generation voltage. The on-time of the current becomes long, the amount of power generated by the generator increases rapidly over the time until the equilibrium state is restored, and the engine speed suddenly decreases, which impairs the drivability of the vehicle.

The present invention has been made in view of the above points, and makes it possible to perform switching control of the generated voltage of the generator so that the load is not suddenly applied to the engine even when an electric load with a large inrush current is applied. The present invention provides a control method for the engine-driven generator.

In order to achieve the object, the present invention is an AC connected in parallel to the battery so that the battery voltage becomes the reference voltage under the control of the controller according to the output signal of the comparator that compares the battery voltage with the preset reference voltage. An on / off control for the field winding of an electric machine, in which the controller measures and holds the on time of the field winding, and the current on time is longer than the previous on time by a predetermined time. When the detection is made, the means for temporarily forcibly switching the power generation amount of the generator to the off side at the time of the detection are provided.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a circuit configuration for specifically implementing the control system of the engine-driven generator according to the present invention. The terminal voltage V _B of the battery 1 and a preset reference generation voltage V _{s are set.}
And a controller CNT that reads the output signal of the comparator CMP and turns on and off the switching element SW that switches the field coil FC in the generator 3 to the stronger side. The reference power generation voltage V _s is equal to the resistance R1 and the resistance R2.
The voltage is set to 14.5 V when the voltage is divided by 14.5 V when the combined resistance of R1 and R2 and the resistor R3 is divided. The switching transistor Tr for turning on and off the resistor R3 includes an air conditioner operation signal S1, a headlamp lighting signal S2,
The deceleration signal S3 is read and turned on or off according to a determination output signal of a logic circuit LOG that determines an electric load state and an engine operating state.

In the configuration as described above, in the conventional case, when the reference voltage V _s changes as shown in FIG. 4 when the electric load (air conditioner) is switched from OFF to ON, the comparator at that time is changed. In response to the output signal of the CMP, the switching element SW is appropriately turned on and off so as to keep the battery voltage V _B at the reference power generation voltage V _s , as shown in FIG. In that case, when V _B <V _s , the output signal of the comparator CMP becomes high level “H” and the switching element SW is turned on, and when V _B ≧ V _s , the output signal of the comparator CMP becomes low level “L”. Becomes the switching element S
W is turned off.

However, if the switching element SW is simply turned on and off in accordance with the output signal of the comparator CMP as described above, when the electric load 4 such as an air conditioner is turned on at the time t1 as shown in FIG. Even if the switching element SW is turned on by switching the reference power generation voltage V _s, it takes a long time Ton until the time t2 at which the switching element SW is restored to the reference voltage V _s . Further, as shown in FIG. 5, the power generation amount of the generator 3 also sharply increases in accordance with the inrush current when the electric load 4 is turned on, and the engine speed Ne also sharply decreases accordingly, and the engine idle-up control is performed. Even if it is done, the engine speed Ne
It is difficult to prevent the engine speed from decreasing because the engine load increases before the response time until the engine rises to the predetermined value.

Therefore, in the present invention, particularly in the controller CNT, means for measuring and holding the ON time of the switching element SW by an internal counter, and means for detecting whether or not the ON time of this time is longer than the previous ON time by a predetermined time, Switching element SW is temporarily forcibly detected
I try to take the means to turn off.

At that time, for example, as shown in FIG.
When the forced off-time tc is provided after the on-time tn obtained by adding the excess time tα to (n-1), the battery voltage V _B that has dropped to the reference voltage V _s or less at the time t1 is restored to the reference voltage V _s again. When the forced off is performed several times during the period Ton ′ until the recovery to t,
Variable control of the ON time such that the initial value of each time of c is set and the ON time is lengthened each time the forced OFF is repeated (in this case, the forced OFF time tc is constant).
Alternatively, variable control of the off time is executed such that the forced off time is lengthened every time the forced off times are repeated. In that case, it is possible to take various methods as follows.

First, when performing variable control of the on-time, as a first method, the current tα time is set as a function of the previous tα (n−1), that is, tα = f {tα (n−1)}, and the current tα is set.
The time is set as a value obtained by adding the constant time K1 to the previous tα (n−1) time, and the tα time is incrementally increased by the constant time K1.

As the second method, tα = f {tα (n
−1)}, the current tα time is changed to the previous tα time.
The (n-1) time is set as a product of a constant coefficient k1, and the tα time is proportionally increased at a constant rate.

As a third method, a function of the number n of forced offs performed until this time tα, that is, tα = f (n)
And the value obtained by adding the value obtained by multiplying the number n of forced off times by a constant coefficient k2 to the previous tα (n-1) time is t
By setting it as α time, tα time is increased at a constant rate in accordance with the number n of forced OFFs.

Further, as a fourth method, this time tα is changed to the previous tα.
(N-1) A function of time and the number of forced off times n, that is, tα = f {tα (n-1), n}, and the previous tα (n
-1) A value obtained by adding a value obtained by multiplying the time by a constant coefficient k1 and a value obtained by multiplying the number of times of forced off n by a constant coefficient k2 is set as the current tα time, and the tα time is set to the previous tα time. The value is increased at a constant rate in accordance with the value tα (n-1) and the number n of forced offs.

Next, when performing variable control of the off time, as a first method, the current tc time is set as a function of the previous tc (n-1), that is, tc = f {tc (n-1)}, and the current tc is set.
The time is set as the previous tc (n-1) time plus the constant time K2, and the tc time is incrementally increased by the constant time K2. In that case, a method of incrementally increasing the above-mentioned tα time by a constant time K1 is also adopted.

As the second method, a function of the number n of forced offs performed until this time tc, that is, tc = f (n)
Then, a value obtained by multiplying the number n of forced offs by a constant coefficient k3 is set as the current tc time, and tc
The time is increased at a constant rate according to the number n of forced off. Also in that case, the above-mentioned method of incrementally increasing the time tα by the constant time K1 is also adopted.

Furthermore, as a third method, the current tc time is set to the previous tc time.
(N-1) A function of time and the number n of forced off, that is, tc = f {tc (n-1), n}, and the previous tc (n
-1) The value obtained by multiplying the time by a constant coefficient k4 and the number of times of forced off n multiplied by a constant coefficient k2 is set as the current tα time, and the tα time is set to the previous tα time. The value is increased at a constant rate in accordance with the value tα (n-1) and the number n of forced offs. Also in that case, the above-mentioned method of incrementally increasing the time tα by the constant time K1 is also adopted.

FIG. 7 shows a controller C for carrying out the present invention.
The flow of processing of NT is shown.

First, it is checked whether the output signal of the comparator CMP is at a high level "H", that is, an ON command of the switching element SW. If the output signal is at a high level "H", then a tα counter (internal of the controller CNT) for measuring tα time. (Provided in the above) and the tα set value B are compared.

At that time, if A ≦ B, the count value of A is incremented, and it is checked whether or not the flag Fa for setting tα and tc is set. If it is set, an ON signal is sent to the switching element SW. An excitation current is supplied to the field coil FC of the generator 3 by giving it. If the flag Fe has not been set, the flag Fe is set, and then the operation subroutine is entered, where tα and tc are reset and an ON signal is given to the switching element SW.

At that time, if A> B, the content of a tc counter (provided inside the controller CNT) for measuring the tc time is incremented, and then the count value C and t are counted.
c Set value E is compared, and if C> E, the content of an n counter (provided inside the controller CNT) that counts the number of forced offs is incremented, and whether the flag Fe is set or not. Then, the same process as described above is performed thereafter. When C ≦ E, the flag Fe is reset and then the switching element SW
The OFF signal is applied to and the field current of the generator 3 is cut off.

If the output signal of the comparator CMP is low level "L", the content of the n counter is set to zero,
After resetting the flag Fe, an OFF signal is given to the switching element SW.

Here, the tα counter and the tc counter function as so-called soft timers for causing the generator 3 to perform soft power generation. A, B, and Fa are initially set to zero.

FIG. 8 to FIG. 11 show the contents of the respective arithmetic subroutines when the first to fourth methods are employed when the variable control of the on-time is performed.

FIG. 12 to FIG. 14 show the contents of the respective arithmetic subroutines when the first to third methods are employed in the case of performing the variable control of the off time described above.

As described above, in the present invention, when the reference generation voltage V _s is switched and the ON period of the field winding current of the generator 3 becomes long, the ON period of the field current is gradually increased to forcibly generate power. Since the generator's power generation is performed while the field current of the generator is cut off, as shown in FIG. 15, even if the electric load 4 with a large inrush current is turned on, the power generation amount of the generator 3 is the same as that of the conventional generator. There is no sudden increase like. Therefore, the load on the engine is lightened and the engine speed Ne does not drop sharply, and the response time Tup 'until the engine speed Ne rises up to a predetermined value when the engine idle-up control is performed is short. As a result, the engine can be idled up with good responsiveness, and the driver's ability of the automobile will not be impaired.

As described above, in the control system for the engine-driven generator according to the present invention, when switching control between the large power generation side and the small power generation side of the generator is performed so that the battery voltage is always the reference voltage, a large electric load is applied. It has an excellent advantage that it is possible to effectively prevent a sudden load from being applied to the engine when the generator is switched to the large power generation side by turning on.

[Brief description of drawings]

FIG. 1 is an electrical connection diagram showing a circuit configuration example for specifically implementing a control system of an engine-driven generator according to the present invention, and FIG. 2 is a circuit diagram showing a connection state of a battery, a generator and an electric load. FIG. 3 is a diagram showing the output current characteristic of the generator with respect to the engine speed, FIG. 4 is a characteristic diagram showing the on / off state of the switching element in the conventional control method with respect to changes in the battery voltage, and FIG. 6 is a time chart showing each characteristic of the ON / OFF state of the switching element, the ON state of the electric load, the power generation amount of the generator, and the engine speed in the control system of FIG. FIG. 7 is a characteristic diagram showing ON / OFF states of switching elements, FIG. 7 is a diagram showing a flow of processing of a controller when carrying out the present invention, and FIG.
FIG. 14 to FIG. 14 are diagrams each showing an example of a calculation subroutine in the flow, and FIG. 15 is an on / off state of a switching element, an on state of an electric load, a power generation amount of a generator, an engine rotation according to the control method of the present invention. It is a time chart showing each characteristic of numbers. 1 ... Battery 2 ... Engine 3 ... Generator 4 ... Electric load CMP ... Comparator CNT ... Controller L
OG ... Logic circuit FC ... Field coil.

Claims (3)

[Claims] 1. A field generator of an alternator connected in parallel to a battery so that the battery voltage becomes a reference voltage under the control of a controller according to an output signal of a comparator comparing the battery voltage with a preset reference voltage. A means for controlling the turn-on and turn-off of the winding, in the controller, means for measuring and holding the on-time in the field winding,
Engine-driven power generation with a means to detect that the current on-time has become longer than the previous on-time by a predetermined amount of time, and a means to temporarily forcibly switch the power generation amount of the generator to the off-side at the time of the detection. Machine control method. 2. The engine-driven power generation according to claim 1, wherein the predetermined time is variably set according to a previous predetermined time and / or the number of times the switch is forcibly turned off. Machine control method. 3. The time for forcibly switching the power generation amount of the generator to the off side is variably set according to the previous switching time to the on side and / or the number of times the power is forcibly switched to the off side. A method of controlling an engine-driven generator according to the above item 1, characterized in that