JP3181422B2 - PWM inverter system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter of a pulse width modulation control system (hereinafter referred to as a PWM inverter), a filter circuit for forming a PWM output voltage into a sine wave, and a transformer having a tertiary winding or more provided therebetween. P composed of containers
In a WM inverter system, the present invention relates to a PWM inverter system that can make a winding output of a tertiary winding or higher into a sine wave by a filter circuit provided on an output side of a converter.

[0002]

2. Description of the Related Art PWM inverter systems for converting a direct current into an alternating current are widely used for a constant voltage / constant frequency power supply and the like because a stable alternating current can be obtained. In a PWM inverter system, a transformer is provided at the PWM inverter output for the purpose of corresponding to a voltage value required by a load. Furthermore, in recent years, the PWM inverter is often used in a forced air cooling system to increase the capacity.

[0003] The configuration of a PWM inverter system currently generally used will be described with reference to FIG. In FIG. 1, a DC power input from a storage battery 2 is converted into AC power by a PWM inverter 3, transformed into a voltage required by a load 8 by a transformer 4, and shaped into a sine wave voltage waveform. Through the circuit 5A, high-quality electric power of a constant voltage and a constant frequency is supplied to the load 8 by a sine wave. The filter circuit 5A is configured by a reactance utilizing the leakage inductance of the transformer 4 and a capacitor of the external filter circuit 5A in order to generate a pseudo sine wave by the PWM inverter 3. The tertiary winding of the transformer 4 is provided for the purpose of insulating the secondary winding from the secondary winding, and the tertiary winding cools the semiconductor element constituting the PWM inverter 3 via the filter circuit 5B. Power supply and PW for cooling fan 6
It is used as a power supply of a control circuit 7 for controlling the M inverter 3.

In such a configuration, the transformer 4
In general, the secondary voltage of the transformer 4 is higher than the primary voltage, and the primary side has a large current and the winding thickness is large. Then, as shown in FIG. 5, the secondary winding 42, the primary winding 41,
It is wound in the order of the next winding 43.

[0005]

In the PWM inverter system having such a configuration, the device structure is reduced in size as a whole due to an improvement in mounting technology and the like. It is essential to reduce the number of points and share parts.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a PWM inverter system in which a sine wave voltage waveform can be obtained without using a filter circuit for a tertiary or higher winding output voltage. Is to provide.

[0007]

In order to achieve the above object, an invention according to claim 1 is a pulse width modulation control type inverter for converting DC power to AC power, and a transformer for converting an AC output voltage of the inverter. A PWM inverter system comprising a transformer having a tertiary or higher winding, and a filter circuit for shaping the output voltage of the secondary winding of the transformer into a sine wave voltage waveform and supplying it to a load. Strange
Coupling the secondary winding of the compressor with the tertiary or higher winding
And the output voltage waveform of the third or higher order winding is filtered.
A PWM inverter system characterized by using a sine wave without using a path .

[0008]

[0009]

[0010]

According to the invention corresponding to claim 1, the transformer 2
Coupling the secondary winding with the third or higher winding; and
Since the output voltage waveforms of the windings of the second and higher windings are made into sine waves without using a filter circuit, the output voltage waveform of the tertiary winding of the transformer is reduced.
Since a filter circuit is not required, the number of parts can be reduced
Compact, capable of highly reliable PWM Inn
A barter system can be provided .

[0011]

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the PWM inverter system of the present invention. Here, the same reference numerals are given to the active elements in FIG. 4 and the conventional example, and the description will be omitted.

FIG. 1 differs from the conventional example of FIG. 4 in that the filter circuit 5B of FIG. 4 which has been conventionally used is not required for the tertiary winding of the transformer 4 in the PWM inverter system 1. It is.

FIG. 2 or FIG. 3 is a view showing an example of a different winding method of the windings of the transformer 4. FIG.
The secondary winding 41, the secondary winding 42, the tertiary winding 43 are wound,
The secondary winding 43 is coupled to the secondary winding 42. FIG. 3 shows a secondary winding 42 and a tertiary winding 4
3, the primary winding 41 is wound, and the tertiary winding 43 is
2 coupled.

The voltage waveform between the terminals of the secondary winding 42 is shaped into a sine waveform by the inductance of the secondary winding 42 and the filtering effect of the filter circuit 5A. By making the coupling between the secondary winding 42 and the tertiary winding 43 dense, the voltage between the terminals of the tertiary winding 43 also has the same waveform as the voltage between the terminals of the secondary winding 42.

Thus, the tertiary winding 43 is connected to the secondary winding 42
To provide a tertiary winding filter circuit between the tertiary winding 43 of the transformer 4 of FIG. 1 and the power supply of the cooling fan 6 and the control circuit 7 connected thereto. Without this, a sine wave voltage can be supplied to both power supplies.

[0017]

As described above, according to the present invention,
Since a filter circuit for the tertiary winding of the transformer is not required, the number of parts can be reduced, and a PWM inverter system that can make the device compact and highly reliable can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a PWM inverter system according to the present invention.

FIG. 2 is a view for explaining an example of the transformer of FIG. 1;

FIG. 3 is a view for explaining another example of the transformer of FIG. 1;

FIG. 4 is a configuration diagram showing an example of a conventional PWM inverter system.

FIG. 5 is a view for explaining the transformer of FIG. 4;

[Explanation of symbols]

1. PWM inverter system 2. Storage battery 3. PWM
M inverter, 4 transformer, 5 filter circuit, 6 cooling fan, 7 control circuit, 8 load.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02M 7/48 H01F 30/04 H02M 1/12

Claims (1)

(57) [Claims] 1. An inverter of a pulse width modulation control system for converting DC power to AC power, a transformer having a tertiary or higher winding for transforming the AC output voltage of the inverter, and a secondary winding of the transformer And a filter circuit for shaping the output voltage of the line into a sine wave voltage waveform and supplying the sine wave voltage waveform to a load, wherein a secondary winding of the transformer and a tertiary or higher winding are coupled.
The output voltage waveform of the third or higher winding.
A PWM inverter system having a sine wave without using a filter circuit .