JPS5810950B2 - Inverter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inverter device that obtains the same alternating current as a commercial power source from a battery of, for example, an automobile.

As is well known, there are various devices that generate AC power from car batteries as auxiliary power sources used during power outages, power sources used outdoors, etc., but an inverter device that outputs a sine wave at a constant frequency is the first to achieve this. has extremely difficult problems.

In other words, this type of inverter device has an output frequency of 50Hz (±1%) or 60Hz (±1%), and an output voltage of 100Vr, m, s (±10%), or 117Vr.
1 m, s (±10%), waveform distortion of within 10% is required, so in order to create a device that satisfies these characteristics, it is necessary to operate the transistor in the form of a power amplifier within the active region. , which is the most preferable form in terms of characteristics,
Considering efficiency, heat generation, cost, weight, etc., there are many problems.

Further, the simplest and cheapest circuit configuration of a DC-AC inverter is a self-oscillation system, but self-oscillation makes it difficult to share 50 Hz and 60 Hz, and fine adjustment of the frequency is not easy.

Furthermore, in the case of self-excited oscillation, the oscillation frequency is easily affected by the size of the load, and the loss in the filter circuit section that shapes the rectangular wave into a sine wave on the output side is large.

The purpose of this invention is to eliminate various drawbacks such as sloping and to provide an inverter with a circuit configuration that converts direct current to alternating current with high efficiency using semiconductor switching elements.The overall configuration is a separately excited type. It uses a push-pull method or a bridge method, and is a type of so-called pulse width modulation method.

That is, invention C provides an inverter device for converting direct current to alternating current, which boosts the direct current voltage of a power source to a high level direct current voltage and then drives a switching element with this high level direct current voltage. Related to this, DC is a means of boosting the DC voltage of a power source to obtain a high-level DC voltage.
-The DC converter has a multi-stage converter circuit whose input side is connected in parallel to the DC power supply, and the DC outputs of each converter are added in series to obtain a DC voltage higher than the DC voltage of the power supply. The inverter is configured as follows, and includes a control section that detects and transmits fluctuations in the high-level DC voltage and pulse-width modulates the driver circuit of the converter, thereby stably controlling the impark output.

Ql and C2 are transistors whose emitters are connected to each other, C3 and C4 are transistors whose emitters are connected to each other, and T, T2 are the transistors Q1, respectively.
．． Q2, C3, and C4 are connected to both ends of each primary coil of a boosting transformer, and its secondary output is connected to a diode D1. D2. D3. D4 and coil T3. A capacitor C is connected to the middle point of the primary coil of the buck-boost transformer T3 through a rectifier circuit 3 consisting of capacitors C3 and C4.
Connected to both ends of 5.

A DC power supply E is connected to both ends of capacitors C1 and C2 connected to the midpoints of the transformers T1 and T2, and switching transistors Q5 and C6 for driving 1 are connected to both ends of the primary coil of the buck-boost transformer T3. The emitters are connected to each other, and each base has an input terminal t1. for a control signal (two input pulses with different phases). t2 is provided, and the two emitters are connected, and the midpoint and the DC power supply E are connected.
It is connected to one side of 1.

Coil L1. L2, capacitor C6, coil L3. L4
, the capacitor C7 is an LC filter circuit 4 connected to the secondary coil of the buck-boost transformer T3.

Further, A is an amplifier circuit that amplifies the error between the output of the rectifier circuit 3 and one end of the DC power supply, and operates the driver circuits 1 and 2 via a pulse width modulation circuit PWM that modulates the pulse width of the output. Furthermore, the driver circuit includes transistors Q1 and C3 and transistors Q3 . Q4 is operated alternately.

The circuit of the present invention configured as described above drives two stages of booster transformers by two transistors each, rectifies the output thereof and feeds it back, and also controls transistors Q5, . Q6 is driven by pulses with different phases, and the large rectangular waveform is shaped into a sine wave by the LC filter circuit 4.

Therefore, low voltage, large current switching is inefficient and difficult to design, but high voltage, small current switching as in the present invention facilitates design and improves efficiency.

In addition, since the voltage applied to the low-frequency oscillator is stabilized, the fluctuation range of the sine wave output voltage is small.Furthermore, since a switching regulator using a multi-series pulse width modulation method is inserted in the series, it is possible to share the output. As the ratios are averaged,
This has advantages such as being able to connect an appropriate number of multiple series.

[Brief explanation of the drawing]

The drawing is a circuit diagram showing an example of the present invention. 1.2... Driver circuit, 3... Rectifier circuit, 4... LC filter circuit, Ql, C
2, C3, C4°C5, C6...Transistor, T1. T2. T3...Trans, E...
...DC power supply.

Claims (1)

[Claims] 1. In an inverter that converts DC to AC, a multi-stage converter is provided whose input side is connected in parallel to the DC power supply, and the DC output of each converter is added in series to the power line between the DC power supply and the inverter input side. A DC-DC converter that obtains a DC voltage higher than the DC voltage of the power supply, a pair of switching elements provided at the subsequent stage of this DC-DC converter, and a converter driver circuit that detects fluctuations in the higher DC voltage. It consists of a control section that performs pulse width modulation, and an LC filter circuit that is provided after the switching element and outputs an alternating current. One switching element is driven by a first pulse signal, and the other switching element is driven by this first pulse signal. An inverter device characterized in that it is driven by a second pulse signal having a phase different from that of the signal.