JPS6082098A - Portable generator - Google Patents

Abstract

PURPOSE:To reduce the size and weight of an engine for driving an AC generator by supplying the output of the generator to a load through rectifying means and an inverter. CONSTITUTION:The output AC of an armature winding 1 of a generator which has a permanent magnet field 3 is supplied to an output terminal 13 through a converter 4 having diodes 4a-4f, a ripple smoothing capacitor 5 and an inverter 6 having transistors 6a-6c and diodes 6e-6h. A controller 10 inputs an inverter current form a current detecting branch unit 7 and an inverter voltage form a voltage detecting transformer 8 and a rectifier 9 and controls the inverter 6 to obtain the AC output of the prescribed voltage in the prescribed frequency. Thus, the rotating speed of a generator can be set irrespective of the frequency, and the size and weight of the engine for driving the generator can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a portable power generator, and more particularly to a portable power generator that obtains alternating current output.

[Background of the invention]

Portable generators are for leisure purposes! l! Although it is becoming more and more popular as an emergency power source for outside engineering, there is a strong demand for small-sized @sulfurized devices for these purposes.

This type of generator, as disclosed in Japanese Unexamined Patent Publication No. 50-41005, uses an engine to drive an AC generator. By the way, in general, when the diameter of the armature of a generator is calculated, the length of the armature is t1, the number of rotations is n, and the output is W, the following relational expression holds true. In this equation, the volume of D"t is proportional to the volume of the armature, so in order to downsize the generator, the smaller the volume, the better. However, since the output frequency of the generator is proportional to the rotation speed n, the output frequency 50 or 60
In order to obtain HZ, the value of n must be constant. For this reason, as is clear from equation (1), the value of D2 t needs to be selected in proportion to the output W, and this has been an obstacle to reducing the size and weight of @electric machines.

[Purpose of the invention]

An object of the present invention is to provide a portable generator that can be made smaller and lighter by using a power generation system that can rotate the generator at high speed without being subject to frequency restrictions.

[Overview of the invention] The main points of the present invention are to rotate the generator at high speed without limiting it to the rotation speed determined by the frequency described above, rectify the obtained AC output to convert it to DC output, and further The f inverter converts this into alternating current with a frequency of j9.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention, in which an output armature coil 1 and a rectifier/power supply circuit armature coil 28 to 2d are wound around a generator armature. Magnetism is provided by a permanent magnet 3, and the output AC of the armature coil 1 is provided by a diode 42~
It is converted into direct current by a converter 4 consisting of 4f and a ripple smoothing capacitor 5, and further by transistors 6a to 5.
．． an inverter 6 consisting of diodes 6e to 6h and diodes 6e to 6h.
It is converted into alternating current and output to the output terminal 13. The control circuit 10 takes in the inverter current given from the current detection shunt 7 into the current limiting circuit 10a, and takes the inverter voltage given from the voltage detection transformer 8 and the rectifier circuit 9 into the automatic voltage adjustment circuit 10b. Signal generation circuit 10C1 Frequency switching circuit 10d, Pulse width modulation circuit 10
e and base drive circuit 12f: controls the inverter 6 via the base drive circuit 12f.

The rectifier power supply circuit 11 supplies power for control.

As a control method for the inverter 6, in this embodiment, P
The WM (pulse width modulation) method is used.

Figures 2A and 2B are diagrams explaining the principle of the PWM method. Figure 2A shows a state where the output voltage is high and the output current is flowing, and Figure 2B shows the state where the output voltage is low and the output current is O. Indicates the condition. The signal generating circuit 10C in FIG. 1 generates a sine wave v1 and a triangular wave v2. The pulse width modulation circuit 106 compares the amplitudes of the sine wave v1 and the triangular wave v2, and outputs a signal v3 to PW8, which is positive when Vl>v2 and negative when V+<Vz, and a PWΔ1 signal V whose positive and negative sides are inverted.
4k occurs. At the time of the PWfvl signal v3, the transistor 6a is turned on via the pace driver 12a,
When the PWM signal v4 is negative, the transistor 6d is turned on via the pace driver 12d. This state occurs at the same time, and during the time width t1, the inverter output is V, and the transistor 6b is in the positive direction.
, 6C are in the off state.

Next, when the PWM signal v3 is reversed to negative and v4 is reversed to positive in the 12 period of FIG. The voltage becomes negative. When the inverter output is controlled P W M flj in this way, the period t of the special type Vs)0 where the sine wave Vl is large
1 becomes large, the period t2 of the small special type v5 becomes large, and the average voltage (fundamental wave) Vso becomes a sine wave with the same frequency as the sine wave v1, as shown in the figure.
Furthermore, the fundamental wave V of the e-window output, which is a sine wave and has a large amplitude of Vl.
The amplitude of SO also increases. Figure 2B shows the sine wave vt'to
At this time, tt=1g, so Vso=0(
The case where the output is 0) is shown. In addition, the output terminal 13
When a single load is connected to the transistor 6, the transistor 6
When d is off, the energy of the load inductance is absorbed by causing a flywheel current to flow through the load path through the transistor 5d, diode 6f, and output terminal 13.

The second output current (5) in the figure shows the case of this inductive load.

In this embodiment, an AC voltage can be generated using a PWM controlled inverter from a DC voltage as described above.
The voltage detector 8 and the rectifier circuit 9 detect the inverter output voltage, and compare this detected voltage with the voltage setting value set in the automatic voltage adjustment circuit 10b, so that the output voltage becomes constant. 10C to sine wave voltage V
Control the amplitude of 1. Therefore, if the AC voltage generated from the output armature coil 1 fluctuates, or the output terminal 13
Even if there are load fluctuations, the AC voltage of the inverter output is controlled to a constant level. In addition, regarding overcurrent of the inverter output, the current is constantly detected by the current detector 7, and compared with the limit value of the stain current by the current limiter circuit 10a.If the limit value is exceeded, the automatic voltage regulator lOb All controls must be taken to ensure that the limit value is not exceeded. That is, when the current limiting circuit 10a determines that the stain current exceeds the limit value, a signal is sent to lower the voltage setting value of the current limiting circuit 10a, and the automatic voltage adjusting circuit 10b also sends a signal to lower the voltage setting value of the current limiting circuit 10a. A signal that reduces the amplitude is sent to the signal generation circuit 10G, which increases the off time of the transistor of the inverter 6 to lower the output voltage V60 and prevent overcurrent, as explained in FIG. 2A.

If this function accidentally shorts the output terminals and short-circuit current flows, or if the output terminals are connected to a commercial power supply and the inverter output voltage is higher than the commercial power supply voltage, the difference voltage will be used. Current flows, but does not exceed the limit value. Conversely, if the inverter output voltage is low and the commercial voltage is high, the inverter can be started by simply charging the smoothing capacitor 5 through the diode in the inverter due to the difference in voltage. It will not be damaged.

Furthermore, the inverter output frequency can be set to 50H2 or 60H2 by setting the frequency of the sine wave Vl by the frequency switching circuit 10d connected to the signal generation circuit 10C.
2, and the output frequency is unrelated to the armature rotation speed n. Therefore, the rotation speed n is selected to be large, thereby reducing the value of D2t in equation (1), that is, the size of the It becomes easier to 1. According to this embodiment, there is no need to install a separate transformer or a PC/DC converter in order to obtain DC voltage between the control circuit and the control circuit of the base drive circuit. By providing the windings 23 to 2d, etc., a voltage can be arbitrarily selected, and a control power supply circuit can be constructed with a simple rectifier circuit. In addition, in the past, the output was taken directly from the armature coil 1, so there was a problem in that when an excessive output current flowed, permanent demagnetization occurred in the field permanent magnet 3 due to armature reaction. However, in this embodiment, even if an excessive output current occurs, it does not cause an excessive current in the coil 1, so there is no need to worry about this.

Fig. 3 shows another embodiment of the present invention, which is different from Fig. 1 in that the field of the generator is not a permanent magnet but a wound wire, and the field wire ring 30f: are doing. Also, rectification times #
N114, voltage regulator 15'! has. The current taken out from the output armature and one phase of the wire ring 1 is transferred to the rectifier circuit 14.
The rectifier current flows through the field wire ring 30 via the voltage adjustment circuit 15, and excites the generator. The output voltage detected by the voltage detector 8 is rectified by the rectifier circuit 9 and then fed back to the voltage regulator 15 to control the field current and keep the output voltage of the generator constant. It has a similar effect.

〔Effect of the invention〕

According to the present invention, since the rotational speed of the generator can be set high regardless of the frequency, the generator and the engine for driving the generator can be made smaller and lighter. It is refreshing to be able to set the rotation speed of the generator drive engine to operate at the minimum point of total fuel consumption, and the speed fluctuations of the generator drive engine due to load fluctuations have an impact on the frequency of the inverter output! It also has the effect of providing a high-quality power source with little frequency fluctuation because it does not affect il.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram showing an embodiment of the invention, FIGS. 2A and 2B are explanatory diagrams of a PWM system, and FIG. 3 is a wiring diagram showing another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Armature coil for output, 2a-2d... Armature coil for rectifier power supply circuit, 3... Permanent magnet for field, 30...
・Field coil, 4... Rectifier, 6... Inverter,
7... ML current/outflow shunt 8... Voltage detection transformer, 9... Rectifier circuit, 10... Control circuit, 11...
- Rectifier power supply circuit, 12...Base drive circuit, 13
... Output terminal, 14... Rectifier circuit, 15... Voltage adjustment circuit. Agent Patent Attorney Masami Akimoto

Claims (1)

[Claims] 1. An AC electric machine driven by a driving means, a rectifying means for rectifying the output current of the generator and converting it into a direct current, and a rectifying means for converting the output direct current of the means into an alternating current of a predetermined frequency. a pulse width modulation type inverter that outputs an output voltage, a limiter that controls the pulse width in the pulse width modulation so that the output current from the inverter does not exceed a predetermined limit value, and an output voltage of the inverter. 1. A portable generator characterized by comprising: a voltage adjusting means for controlling the voltage 111iI so that the voltage becomes the set value. 2. The AC generator is a permanent magnet field type synchronous generator, and the voltage adjustment means adjusts the voltage by dividing the pulse width in pulse width modulation according to the detected value of the inverter output voltage. The portable generator according to claim 1, characterized in that the portable generator is configured to perform adjustment. 3. The alternating T generator is a winding field type synchronous generator, and the voltage adjustment means adjusts the voltage by controlling the current of the field winding according to the inverter output voltage. A portable generator according to claim 1, characterized in that the portable generator is configured as follows. 4. The DC power supplied to the control circuit for controlling the operation of the inverter, the limiter, and the voltage adjustment means is obtained by rectifying the output of the auxiliary wire provided on the armature of the alternating current generator. A portable generator according to claim 1, 2, or 3, characterized in that: