JPH0528068B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is directed to converting the output from an internal combustion engine-driven power generator, particularly an alternator driven by an internal combustion engine, into direct current, which is then converted into direct current by an inverter circuit. In an internal combustion engine-driven power generation device that converts the DC output into an AC voltage having a predetermined frequency, a step-up chopper-type switching regulator is used to control the DC output to a predetermined DC voltage level under the condition where the DC output is converted to DC voltage, Absorbs the voltage fluctuation of the above AC generator,
The present invention also relates to an internal combustion engine-driven power generation device in which the output of the regulator is limited to below the maximum output of the generator.

[Conventional technology]

Conventionally, internal combustion engine-driven power generation devices have been designed to prevent the frequency of the AC output from the generator from fluctuating due to fluctuations in the rotational speed of the internal combustion engine, and to generate large output from a relatively small generator. In order to achieve this, a configuration is adopted in which the output of the generator is first converted to direct current and then converted to alternating current voltage at a predetermined frequency.

Even in the case of this configuration, when a permanent magnet field generator is used, the problem is how to suppress fluctuations in the output voltage of the generator caused by fluctuations in the rotational speed of the internal combustion engine. In order to suppress fluctuations in the output voltage of the generator, it is possible to take measures such as changing the ignition timing of the internal combustion engine by delaying the ignition timing and changing the rotational speed of the internal combustion engine. It is being done. However, in the case of a configuration in which the rotational speed of the internal combustion engine is controlled in order to suppress fluctuations in the output voltage as described above, the delay time constant existing in the control loop is large, making it difficult to configure the control system.

In addition, in the internal combustion engine-driven power generation device that obtains an AC voltage of a predetermined voltage at a predetermined frequency, the device used in Japan is designed to obtain an AC voltage of 100 [V], but the device used in foreign countries It is necessary to obtain an AC voltage of 230 [V], and in order to deal with the above problem, it cannot be solved by adjusting the rotation speed of the internal combustion engine, so two types of generators are prepared. , it is necessary to select a generator for use in Japan or abroad.

In order to solve these various problems, the applicant first used a chopper-type switching regulator, and in the chipper-type switching regulator, applied pulse width modulation to keep the output voltage of the regulator at a constant value. The switching element is turned on and off by the signal obtained by
He proposed converting the regulated output voltage of the regulator into AC voltage using an inverter (Patent Application No. 1989-289784 filed on December 23, 1985).
issue).

Figure 4 shows the configuration shown in the above proposal.
is an internal combustion engine driven generator, 2 is a rectifier circuit, 3 is a step-up chopper type switching regulator, 4
5 is an inverter circuit, 5 is a pulse width modulator, 6 is a switching element, 7 is an inductance element, 8 is a diode, and 9 is a capacitor.

As the internal combustion engine driven generator 1, a generator with a permanent magnet field is used. The generated alternating current voltage is then converted into direct current voltage by the rectifier circuit 2. The chopper type switching regulator 3 includes a pulse width modulator 5 that modulates the pulse width in accordance with the voltage level of the DC voltage on the output side of the regulator 3, and a switching element 6 that is turned on and off by the modulator 5. It is equipped with Then, the voltage level of the DC voltage on the output side of the regulator 3 is maintained constant. Inverter circuit 4
converts the DC voltage maintained at a constant voltage level into an AC voltage having a predetermined frequency.

A generator 1 driven by an internal combustion engine generates an alternating current voltage whose frequency and voltage change in response to changes in the rotational speed of the internal combustion engine. The AC voltage is converted into DC by the rectifier circuit 2. The voltage is maintained at a constant DC voltage level by the chopper type switching regulator 3, and then converted by the inverter circuit 4 into an AC voltage having a predetermined frequency and a predetermined voltage level.

In the above configuration, 100
When trying to obtain an AC voltage of [V] and an AC voltage of 230 [V] for use in a foreign country, the following procedure is performed. That is, as the tipper type switching regulator 3, the above-mentioned
If 230 [V] is required, use a step-up type to boost the DC voltage level to, for example, about 90 [V] and then supply it to the inverter circuit 4.
If the above-mentioned 100 [V] is required, a step-down type is used to step down the DC voltage level of about 90 [V] and then supply it to the inverter circuit 4.

[Problem that the invention seeks to solve]

In the case of the previous proposal as shown in FIG. 4, it has become clear that the following problems arise, especially when a boost type regulator is used as the regulator. That is, when trying to start the induction motor connected to the load side of the inverter circuit 4, a large starting current flows and the output side voltage of the regulator 3 tends to drop. For this reason, the regulator 3 works to suppress the voltage drop, and as a result, it works to supply an output higher than the maximum output of the generator 1 to the load side.

FIG. 5 is an explanatory diagram schematically explaining the situation during this period. In the case shown in the figure, the regulator 3 is
The operation when maintaining the output voltage at V _N is as shown in the illustrated characteristics. That is, the voltage of the generator decreases as the current increases, but until the output of the generator reaches the maximum output Pmax, the regulator 3 maintains a constant voltage V regardless of the decrease in the voltage of the generator 1. Works to output _N.
However, after the output of the generator 1 reaches the maximum output, the load current of the regulator 3 increases.
The output voltage of will also decrease correspondingly.

If the step-up ratio in the regulator 3 is limited to not exceed the value "2", the characteristics as described above will be followed, but the regulator 3
In the case of operation in which the output voltage of the regulator 3 is maintained at V _N under a condition where the step-up ratio of the regulator 3 can increase up to "3", the characteristic shown is shown, and the step-up ratio of the regulator 3 can increase up to "4". In the case of operation that maintains the output voltage of the regulator 3 at V _N under the following conditions, the characteristics shown are obtained. In other words, point A where the output voltage of regulator 3 is V _N and the output current is I _N
When the output current attempts to further increase after reaching , the output voltage of regulator 3 rapidly decreases.
In the case of the characteristic, the voltage drops to zero all at once.

[Means for solving problems]

The present invention solves the above-mentioned problems, and when working to maintain the output voltage from a step-up chopper type switching regulator at a predetermined value, the step-up ratio of the regulator is set to a predetermined value corresponding to the output voltage. I am trying to use a regulator that limits it to a certain value.

FIG. 1 shows a basic configuration diagram of the present invention. In the figure, reference numeral 1 represents a generator, 2 represents a rectifier circuit, 3 represents a step-up chopper type switching regulator, and 4 represents an inverter circuit. Further, 10 represents a boost ratio limiting means.

[Effect]

The overall operation of the arrangement shown in FIG. 1 is essentially the same as that shown in FIG. That is, the output voltage from the generator 1 is rectified by the rectifier circuit 2, the regulator 3 operates to maintain its own output voltage at a predetermined voltage, for example, _VN , and the DC output from the regulator 3 is sent to the inverter circuit 4. is converted into AC voltage by At this time, in the case of the configuration shown in FIG. 1, the boost ratio in the regulator 3 is limited so as not to exceed a predetermined value. That is, it is preset by the illustrated step-up ratio limiting means 10 at the time of shipment.

The maximum allowable step-up ratio mentioned above is based on the rated output voltage of the regulator 3, for example, _VN , and the generator 1.
The value is determined by dividing by the output voltage of the generator 1 (V _n shown in FIG. 5) corresponding to the maximum output Pmax of .

Taking the case shown in FIG. 5 as an example, the step-up ratio is limited to the value (V _N /V _n ). By doing this, the overall output characteristics will conform to the characteristics shown in FIG.

〔Example〕

FIG. 2 shows the configuration of an embodiment of the present invention. Reference numerals 1 to 10 in the figures correspond to FIGS. 1 and 4.

The boost ratio of the regulator 3 is determined by the ratio between the on period and the off period of the switching element 6 in one cycle. That is, by limiting the ON period of the switching element 6 whose base is connected to point a in FIG. 2 so as not to exceed a predetermined value, it is possible to limit the boost ratio.

By changing the voltage at point b in the figure in the range of 0 [V] to 3.3 [V], the on period of the switching element 6 can be changed in the range of 97 [%] to 0 [%] (pulse width (When Texas Instruments T1494 is used as modulator 5). That is,
As shown in FIG. 3A or B, by changing the voltage (threshold level) at point b from 0.1 [V] to 3.3 [V], the on period of switching element 6 can be changed.
It varies from 97 [%] to 0 [%].

Focusing on this point, the boost ratio is set to be limited to a predetermined value or less. That is, under the condition that the capacity of the generator is determined in advance and the rated output voltage of the regulator 3 is designed to be 200 [V], the resistor Rb is installed in the step-up ratio limiting means 10.
is connected, and in order to cope with specifications in which the rated output voltage of the regulator 3 is 230 [V], the resistor Rd shown in FIG. 2 should be added and the resistor Rb should be removed. That is, the product is shipped to the user in a preset state as described above. In other words, the regulator 3 is manufactured with the resistor Rb and the resistor Rd installed in the step-up ratio limiting means 10, and the rated output is
For users of 200 [V], remove resistor Rd,
For users with a fixed output of 230 [V], resistor Rb should be removed.

In addition, for simplicity, point b and point c are made common,
It is also possible to change the potential at point c.

〔Effect of the invention〕

As explained above, according to the present invention, the step-up ratio of the regulator is limited to a predetermined value or less in response to the rated output voltage of the regulator, or is configured to be able to be limited. Therefore, an undesirable operating condition such as that described in connection with FIG. 5 will not occur.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle configuration of the present invention, Fig. 2 is a configuration of an embodiment of the present invention, Fig. 3 is an explanatory diagram of operation, Fig. 4 is a configuration based on the premise of the present invention, and Fig. 5 is a problem. An explanatory diagram for explaining is shown. In the figure, 1 is a generator, 2 is a rectifier circuit, 3 is a step-up chopper type switching regulator, 4 is an inverter circuit, 5 is a pulse width modulator, 6 is a switching element, 7 is an inductance element, 8 is a diode, 9 represents a capacitor, and 10 represents a step-up ratio limiting means.

Claims (1)

[Claims] 1. An alternator driven by an internal combustion engine;
a rectifier circuit that rectifies the output of the alternator; a constant voltage control circuit that maintains the DC output from the rectifier circuit at a predetermined DC voltage level; and a constant voltage control circuit that maintains the DC voltage level at the predetermined DC voltage level. and an inverter circuit that converts a DC voltage into an AC voltage having a predetermined frequency. It is constituted by a step-up chopper type switching regulator that has a pulse width modulator that performs modulation and a switching element that is turned on and off by the pulse width modulator, and that the switching element is kept in the off state. the voltage level of the constant voltage control circuit, and the limiting means detects the voltage level of the output voltage of the constant voltage control circuit and applies the voltage level to the pulse width modulator. The voltage level of the detected output voltage, which is provided corresponding to the supplied output voltage detection section, is
The voltage corresponding to the step-up ratio is forcibly limited to a value corresponding to the step-up ratio, and the value corresponding to the step-up ratio is the voltage value of the alternator that corresponds to the voltage value to be supplied to the inverter and the maximum output of the alternator. An internal combustion engine-driven power generator characterized in that the power generation device is set in advance according to a ratio to an output voltage value.