JPH05292799A - Engine generator - Google Patents

Abstract

PURPOSE:To provide an economic engine generator by reducing cost of starter inverter, i.e., a forward converting section. CONSTITUTION:The engine generator comprises an AC generator 4 coupled with an engine, a power converter 5 comprising a converting section 6A and an inverting section, and a battery 10 for starting engine, wherein the converting section 6A is operated as an inverter with the battery 10 as a power supply and the AC generator 4 is operated as a motor with the output from inverter. In such engine generator, the converting section 6A is constituted of a half- bridge circuit and the engine generator further comprises pole position detectors 36R-36T for detecting the pole position of each phase of the AC generator 4 and a phase distributor 37 producing a driving signal for each switching element in the converting section 6A based on the outputs from the polarity detectors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises an AC generator connected to an engine, a power converter having a forward converter, an electrolytic capacitor and a reverse converter, and an engine starting battery. The present invention relates to an engine-type power generator that drives the forward conversion unit as a power source with an inverter and drives the alternating-current generator with a motor by the output of the inverter.

[0002]

2. Description of the Related Art FIG. 5 shows the structure of a conventional portable engine-type power generator. In the figure, 1
Is a fuel tank, 2 is a fuel supply device (injector), 3
Is a gas turbine engine (hereinafter, simply referred to as an engine) E, 4 is a magnet type three-phase synchronous generator (hereinafter, simply referred to as a generator) SG, 5 is a power converter, and Lo and Co constitute a filter circuit. A reactor and a condenser.
The power converter 5 includes a forward converter 6, an electrolytic capacitor 7, and a reverse converter 8. 9u and 9w are output terminals.

The generator 4 has auxiliary windings for auxiliary machines in addition to the main windings. The voltage Vs generated by the auxiliary winding is taken into the rotation speed detector 20 and used to detect the generator rotation speed, and the detected rotation speed N is the rotation speed command value N ^*.
And the deviation is given to the fuel supply device 2 through the deviation amplifier 21, and the fuel supply device 2 is controlled so as to eliminate the deviation. Vp is a voltage generated in the main winding.

[0004] rectifier unit 6, as shown in FIG. 6, has a transistor Q ₁ to Q ₆ of bridge-connected 6箇, the diode D ₁ to D ₆ which are connected in antiparallel, respectively. Further, as shown in FIG. 6, the inverse conversion unit 8 has four transistors T _{r1 to} T _r4 which are bridge-connected and four diodes D _{7 to} D ₁₀ which are respectively connected in anti-parallel to each other. .. Reference numeral 25 denotes a main part of the control circuit of the inverse conversion unit 8. 26 is a deviation amplifier, 27 is a PWM signal generator, 28
And 29 are dead time circuits, and 30 to 33 are base drivers. Reference numeral 34 is a control circuit of the forward conversion unit 6, and like the control circuit 25, has a base driver for supplying a base current to each of the transistors Q _{1 to} Q ₆ , a PWM signal generator, a feedback circuit, and the like.

A battery 10 for an engine starter is connected to a DC circuit of the power converter 5 via a step-down chopper circuit 11. The step-down chopper circuit 11 includes a chopper element 12, a reactor 13, and a diode 14. Reference numeral 15 denotes a charging current control circuit, which converts the charging current I _B detected by the current sensor 16 into a charging current command value I
Deviation amplifier 17, P that compares with _B ^* and amplifies the deviation
A PWM signal generator 18 for generating a WM signal is provided, and this PWM signal is applied to the base of the chopper element 12 via a switch 19 to control the chopper element 12. SW is a switch.

In this apparatus, when the engine 3 is started, the switch SW is closed, the battery 10 is connected to the main circuit, and one of the transistors forming the inverse converter 8 is connected.
(Transistor T _r3 ) and the reactor Lo of the filter circuit 6 are used to form a boost chopper circuit, which boosts the voltage of the battery 10 and causes the transistors Q _{1 to} Q ₆ of the forward conversion unit 6 to perform reverse conversion operation. The phase AC voltage is extracted and the three-phase AC voltage is applied to the generator 4 to drive the generator 4 as a motor.

After the engine 3 has been started, the battery 10 opens the switch SW and operates the step-down chopper circuit 11 to charge the battery 10.

The output of the generator 4 is converted into direct current by the diode bridge of the forward converter 6, then converted into alternating current of a desired voltage and frequency by the inverse converter 8, and supplied to the load through the filter circuit. FIG. 7 shows transistors T _{r1 to} T _r4.
The operation sequence of is shown.

[0009]

Since this type of portable engine-type power generator is required to be as inexpensive as possible, the number of parts can be reduced as much as possible and inexpensive parts can be used. Are making design efforts.

Regarding the forward conversion section 6 which is driven by an inverter when the engine is started, conventionally, six transistors Q ₁ to
Although a bridge circuit using Q ₆ and six diodes D _{1 to} D ₆ has been used as a matter of course, the transistors Q _{1 to} Q ₆ are the transistors T _{r1 to} T _r4 of the inverse conversion unit 8.
Since it often requires a capacitance of about 1/3 of the above, it is expensive and requires 6 base drivers, 12 base wirings, and 4 potentials of insulating power supply for base circuit. Therefore, the price of the forward conversion unit 6 and its control circuit 26 accounts for a large percentage of the total price of the power conversion device 5, and if the cost of the forward conversion unit 6 and its control circuit 26 can be reduced, economical power generation is possible. It can be a device. Moreover transistors Q ₁ to Q ₆ of the rectifier unit 6 only when the engine is started, 30 seconds to 1 minute, because those operating, its efficiency is poor, which is uneconomical. The present invention has been made to solve this problem, and provides an engine-type power generator that can reduce the cost of a forward conversion unit, which is an inverter for a starter, as compared with the conventional one, and can improve economic efficiency. The purpose is to

[0011]

To achieve the above object, the present invention provides, in claim 1, an AC generator connected to an engine, a power converter having a forward converter, an electrolytic capacitor, and a reverse converter, and an engine. In an engine-type power generation device that includes a starting battery and drives the forward conversion unit with an inverter using the battery as a power source when the engine is started, and drives the AC generator as an electric motor with the output of the inverter, the forward conversion unit includes six forward conversion units. It is a half bridge circuit consisting of a diode and three switching elements, has a magnetic pole position detector for detecting the magnetic pole position of each phase of the AC generator, and drives the switching elements based on the output of the magnetic pole detector. It has a configuration including a phase divider that generates a signal.

According to a second aspect of the present invention, the inverse conversion section is a bridge circuit composed of positive side and negative side switching elements and positive side and negative side electrolytic capacitors, and an intermediate point of both electrolytic capacitors during driving thereof. The generator is connected to the neutral point, and the neutral point of the generator is connected to one pole of the DC circuit of the power converter when the engine is started with the generator operating as a motor.

[0013]

In the present invention, since the number of switching elements to be used is halved because the forward conversion section is a half bridge, the peripheral circuit parts such as the base circuit are also halved. It is possible to realize a large cost reduction and a compact control circuit.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the forward converter 6A of the power converter 5 has a half-bridge type circuit configuration. Further, the neutral point 4O of the generator 4 is drawn out through the lead 41, and this lead end is connected to the positive electrode of the DC circuit of the power conversion device 5 via the switch 35. 4R, 4S,
4T represents the R phase, S phase, and T phase windings of the generator 4. 36
R, 36S and 36T are magnetic pole position detectors (in this example, magnetic flux sensors). 37 is a magnetic flux sensor 36R, 3
The magnitudes of the magnetic fluxes output by 6S and 36T Φ _R , Φ _S ,
It is a phase divider that generates drive signals I _bR , I _bS , and I _bT for each phase having an electrical angle of 120 ° based on Φ _T , and transistors Q ₄ and Q through base drivers 38 R, 38 S, and 38 T, respectively. ₅ and Q ₆ are supplied to the base.

FIG. 2A shows the magnetic fluxes Φ _R , Φ _S and Φ _T.
In FIG. 2B, the O of transistors Q ₄ , Q ₅ , and Q ₆
An N / OFF operation is shown. FIG. 2C shows the rotating magnetic field generated in the generator 4.

In this structure, when the engine 3 is started, the switch 35 and SW are closed. Battery 1
The voltage V _B of 0 is boosted by the boosting circuit described above, and assuming that the boosted voltage is αV _B , the voltage αV _B is sequentially applied to the windings 4R, 4S, 4T through the transistors Q ₄ , Q ₅ , Q _6. Will be done. Transistors Q ₄ , Q
_{Since 5} and Q ₆ are sequentially conducted in this order, the R-phase winding 4
Currents are sequentially supplied to the R, S-phase windings 4S, and T-phase windings 4T, a rotating magnetic field shown in FIG. 2C is generated, and the generator operates as a thyristor motor, and the engine 3 operates. It is started.

In this embodiment, the number of transistors in the forward conversion unit 6A is 6 to 3 as compared with the case of the conventional forward conversion unit 6.
The number of base drivers required,
The required number of base wirings will be halved, and the insulating power supply will only need one potential.

Further, if the voltage / rotation speed ratio of the generator 4 is the same, the main circuit DC voltage of the power conversion device 5 at the same rotation speed is low, so that higher rotation is possible with the same main circuit DC voltage. ..

FIG. 3 shows another embodiment of the present invention, in which the inverse conversion unit 8A of the power conversion device 5 connects the transistors T _r1 and T _r3 of the inverse conversion unit 8 of FIG. 6 to the electrolytic capacitor C1. And C3 are replaced by the circuit configuration. Also,
The lead 41 end of the neutral point 4O of the generator 4 is connected to the connection point a of the electrolytic capacitors C1 and C3 via the switch 39.

In this structure, when the engine 3 is started, the switches 35 and SW are opened and the switch 39 is opened.
Closes and drives transistors Q ₄ , Q ₅ , Q ₆ as described above.

After the start-up is completed, the switches 35 and SW are closed and the switch 39 is opened. The voltage generated by the generator 4 is converted into direct current by the diode bridge of the forward conversion unit 6A, and this direct current voltage (2 × E, for example, 200 V) is applied to the series circuit of the electrolytic capacitors C1 and C3, Both C1 and C3 are charged to voltage E. The transistors T _r2 and T _r4 are ON / OFF controlled, for example, as shown in FIGS. 4A and 4B, and the sinusoidal single-phase AC shown in FIG. 4D is taken out from between the output terminals 9u-9w. ..

In this embodiment, since one arm of the inverse converter 8A is an arm of the electrolytic capacitor, the number of switching elements used is halved, and the peripheral circuit parts such as the base circuit are halved accordingly. The cost of the inverse conversion unit can be reduced, and as described above, the forward conversion unit 6A
Since the cost can be reduced, the price of the power conversion device 5 can be significantly reduced and the control circuit unit can be made compact.

Further, in the case of the embodiment of FIG. 3, assuming that the output voltage and the output current are the same as those of the conventional one,
Since the power supply voltage of the power conversion device 5 is doubled, the current capacity of the diode of the forward conversion unit 6A is halved, and when the power receiving current is halved, the wire diameter is small. be able to.

[0025]

As described above, according to the present invention, the number of switching elements used is halved by using the half-bridge as the forward converter, and accordingly, the peripheral circuit parts such as the base circuit are halved. In addition, it is possible to realize a large cost reduction of the power converter and a compact control circuit, and it is possible to reduce the price of the entire power generator.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a waveform of each part for explaining the operation of the forward conversion part in the above-mentioned embodiment.

FIG. 3 is a configuration diagram showing another embodiment of the present invention.

FIG. 4 is an operation sequence and waveform diagram of an inverse conversion unit in the other embodiment.

FIG. 5 is a configuration diagram of a conventional engine-type power generator.

FIG. 6 is a circuit diagram of a forward conversion unit and an inverse conversion unit in the above conventional engine-type power generator.

FIG. 7 is an operation sequence and waveform chart of the inverse conversion unit in the conventional engine-type power generation device.

[Explanation of symbols]

 1 Fuel Tank 2 Refueling Device 3 Gas Turbine Engine 5 Power Converter 6A Forward Converter 7 Electrolytic Capacitor 8A Reverse Converter 10 Battery 15 Charging Control Circuit 16 Deviation Amplifier 19, 35, 39 Switch 36R-36T Magnetic Pole Position Detector 37 Phase Distributor 38R-38T Base driver C1, C3 Electrolytic capacitor

Claims (2)

[Claims] 1. An alternating current generator connected to an engine, a power converter having a forward converter, an electrolytic capacitor, and a reverse converter, and an engine starting battery. When the engine is started, the battery is used as a power source for the forward converter. In an engine-type power generator that drives the AC generator as an electric motor by operating the inverter with the inverter output,
The forward conversion unit is a half bridge circuit of a diode and a switching element, has a magnetic pole position detector for detecting the magnetic pole position of each phase of the AC generator, each of the forward conversion unit based on the output of the magnetic pole detector And a phase divider that generates a drive signal to be applied to the switching element. 2. The inverse conversion unit is a bridge circuit composed of positive side and negative side switching elements and positive side and negative side electrolytic capacitors, and the middle point of both electrolytic capacitors during driving is a generator circuit. The neutral point of the generator is connected to one pole of the DC circuit of the power conversion device at the time of engine start, which is connected to the neutral point and the generator is operated by a motor. Engine type power generator.