Drive circuit of motor and outdoor unit of air conditioner

Abstract

The object of the present invention is to obtain a drive circuit for a motor and an outdoor unit of an air conditioner using the drive circuit, wherein the low noise and low loss obtained by making the power wiring low inductance can be maintained without wasting materials. It can flexibly respond to the modification of low-priced and small-volume products, and the stress of the welded part due to self-heating is small, the welding reliability is high, and there are few design restrictions. The motor drive circuit of the present invention is a motor drive circuit that uses a conversion circuit and an inverter circuit to drive a motor, and is characterized in that it has a lead frame molded substrate (100) and a single-sided printed circuit board (31) for a control circuit. , the lead frame molding substrate is mounted with electronic parts constituting the conversion circuit and the inverter circuit, and utilizes the molding resin (36) to mold the metal plate leads (37), and the power supply terminals (30) of the electronic parts are molded with the lead frame The substrate (100) is connected, and the control wiring terminal (39) of the electronic component is connected to the single-sided printed circuit board (31).

Description

technical field [0001] The present invention relates to a drive circuit of a motor using an inverter and an inverter, and an outdoor unit of an air conditioner using the drive circuit. Background technique [0002] At present, for an inverter circuit having a semiconductor switching element and a smoothing capacitor, there are proposals for a power supply module having a substrate on which a conductor pattern is formed and a semiconductor switching element mounted thereon, mounting the substrate, forming a contoured case, and smooth mounting. A capacitor, a wiring pattern made of a conductive metal inserted into a molded resin, a molded substrate for connecting a smoothing capacitor to the wiring pattern, and a terminal for a molded substrate having taps provided on a case, wherein the molded substrate is screwed It is fixed to the tap of the terminal for the molded substrate, and the molded substrate is mounted on the case, and an inverter circuit is formed by electrical co...

AI Technical Summary

Problems solved by technology

In order to obtain the number of insert-molded substrates on which smoothing capacitors are mounted, it is necessary to standardize products of various capacity bands using substrates of the same shape. In this case, it is necessary to standardize using smoothing capacitors of the largest capacity model. wasteful material is used on lower volume models of

Since the smoothing capacitor is one of the largest parts in the inverter circuit like the reactor, the wasted material cannot be ignored compared with the case of mounting on the printed circuit board

[0010] In addition, since the electrode and the substrate on the case forming the outline of the substrate on which the switching element are mounted are in plane contact and are joined by soldering, the strength of the solder against thermal shrinkage is weak.

[0011] Moreover, the existing circuit is to install the power device on the printed circuit board intact, and the high-voltage and high-current wiring required for the pattern width and pattern distance are arranged on the printed circuit board, and the area efficiency is low.

And lead to the enlargement of the electronic parts box itself

[0012] In addition, the wiring inductance also increases, and the generated noise also increases.

Moreover, the temperature at the base of the power component rises significantly, which limits the service life of the solder by design

[0013] In addition, since copper foil wiring is produced by etching on printed circuit boards or metal substrates, in the case of producing wiring for power wiring of thick copper foil, the etching time is long and the unit price of the substrate is increased.

In the case of production on the same substrate, thin wiring such as control wiring is also formed with thick copper foil, wasting material

[0014] In addition, in the conventional inverter circuit shown in Patent Document 2, the power supply elements are fixed by screws, so screws are required, which increases the price.

In addition, screw tightening requires processing time, and the processing cost also increases, so it is not suitable for mass production of mass-produced circuits such as inverters for air conditioners.

In addition, a method of attaching connectors or metal terminals by soldering and bonding to a printed circuit board is also considered, but connectors and leads are required, and processing time for wire bonding is also required.

Moreover, since screw tightening and connector connection are manual operations, there is a high probability of joint failure

In the case of poor connection, the temperature rise caused by the poor contact of the power supply part is high, and there is a high risk of smoke and fire.

In order to avoid the above situation, it is necessary to spend time on the inspection process

[0015] In addition, in the conventional inverter circuit shown in Patent Document 2, electrolytic capacitors for level smoothing are mounted and wired on a substrate for power supply wiring that is more expensive than a printed circuit board, but the area of ​​the original parts is large and It is not economical to mount an electrolytic capacitor with simple wiring on a substrate for power wiring

In addition, the capacity of electrolytic capacitors varies greatly from model to model. If the substrates are standardized for the maximum capacity, too much waste will be wasted on models of electrolytic capacitors that are used in large quantities and that have a small capacity.

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