JP2006262633A - Converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a converter that comprises a controller for an inverter for the drive of a motor that is small, light in weight, and capable of removing the noise. <P>SOLUTION: This converter is provided with a rectifying circuit that inputs AC power source 1. The converter comprises a diode bridge 4 and a capacitor 5 of a small capacity, provided on the DC-output side of the diode bridge 4, an inverter circuit 2 that converts DC power into AC power, and a motor 3. A reactor 6 is connected to each input of the R phase and T phase of the rectifying circuit. The reactor 6 is magnetically coupled so as to generate inductance, in both the normal mode and the common mode. Electromagnetic noise can be reduced and miniaturization, weight reduction, and cost reduction of the converter can be achieved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a converter device including a motor driving inverter control device that drives a motor by an inverter.

  A conventional converter device rectifies an AC input with a diode and smoothes it with a capacitor to obtain a DC output, and this DC output is connected to a load. For this reason, an input current flows during a period when the voltage of the smoothing capacitor, that is, the DC output voltage is lower than the AC input voltage. This input current flows in a short period of time when the DC output voltage is lower than the AC input voltage, and also flows later than the AC input voltage, leading to a reduction in power factor.

  Furthermore, since it flows in a short time, the input current does not become the same sine wave as the AC input voltage, but is spire. The spire-shaped input current includes a power supply harmonic current that is a frequency component that is a positive multiple of the fundamental frequency. This power supply harmonic current induces various troubles to other devices via the commercial power supply. On the other hand, the load of the converter device often includes a switching circuit that generates electromagnetic noise. For this reason, it is necessary to provide a new noise filter for suppressing electromagnetic noise on the power receiving side, that is, the input side of the converter device, resulting in an increase in size and cost of the entire device.

  In view of this, a converter device that can reduce the power harmonic current and improve the power factor, and is small, inexpensive, and achieves low electromagnetic noise has been proposed (see, for example, Patent Document 1). A converter device using this method will be described.

  FIG. 2 is a circuit diagram of the converter device. Reference numeral 101 denotes a load including a switching circuit, 102 denotes a single-phase input and capacitor smoothing converter, 103 denotes a reactor, 501 is a noise filter, and 104 is an AC power supply.

  Reactor 103 is inserted into each of the R-phase and T-phase inputs of the capacitor smoothing rectifier circuit with AC input 104. Reactor 103 is electrically isolated so that the R and T phases are electrically isolated and magnetically independent, or is magnetically coupled so as to preferentially generate a normal mode inductance, and / or Both the normal mode and the common mode are magnetically coupled so as to generate inductance. Then, a noise filter is inserted into one or both of the input and output of the reactor 103.

  In the converter device configured as described above, the reactor inserted into each of the R-phase and T-phase inputs widens the conduction width of the input current, reduces the power supply harmonic current, and improves the power factor. In addition, both normal mode and common mode electromagnetic noise are suppressed. This makes it possible to reduce the power supply harmonic voltage and electromagnetic noise and improve the power factor.

  Here, even if the reactor is inserted into one of the R phase and the T phase, it is possible to improve the power factor and suppress the power supply harmonic current and normal mode noise that travel between the R phase and the T phase. However, only one phase is effective against common mode noise, and it is impossible to suppress the common mode noise of the other phase. Therefore, the common mode noise can be suppressed by inserting the reactor 103 in the R phase and the T phase.

  Further, the noise filter 501 removes mainly high frequency noise, which is not sufficient only by the noise suppression effect by the reactor 103. Therefore, the dependence of noise suppression on the noise filter is reduced, and the number of elements and constants constituting the noise filter can be reduced.

Although there are various circuit configurations of the noise filter 501, due to the reduction of attenuation, the common mode choke coil Lc, the X capacitor Cx that shunts the R phase and the T phase, and the Y capacitor Cy between each phase and the ground are used here. It is configured. The Y capacitor Cy is set regardless of the presence or absence of the reactor 103 in order to effectively use the upper limit value of the leakage current limit. However, the X capacitor Cx and the common mode choke coil Lc need only have values of about 1/10 and 1/2 of the circuit configuration in which the reactor 103 is not inserted. Therefore, the noise filter 501 can be reduced.
JP-A-10-201221

  However, in the conventional converter device, when the inverter control device drives the motor as a load, the reactor 103 and the smoothing capacitor constituting the converter 102 cause distortion of current flowing from the power source into the motor drive inverter control device. In order to avoid deterioration of the power factor due to the above, a large capacity is used.

  That is, in the case of a converter device having an inverter control device for driving a motor, when the dose of the smoothing capacitor and the reactor is reduced, the power factor is deteriorated due to the distortion of the waveform of the current flowing from the power source to the motor, and the harmonic component is accordingly accompanied. Increasingly, the international harmonic regulation, IEC (International Electrotechnical Commission) harmonic regulation, cannot be satisfied. Therefore, there is a problem that the entire apparatus is increased in size and cost.

  The present invention has been made in order to solve the above-described problems, and an object thereof is to provide a converter device having an inverter control device for driving a motor that is small and lightweight and can eliminate noise. Yes.

  In order to solve the above-described conventional problems, a converter device according to the present invention includes an AC power source, a rectifier circuit including a diode bridge, a small-capacitance capacitor provided on the DC output side of the diode bridge, and a DC power. An inverter circuit for converting to AC power and a motor are provided, and a reactor is connected to each of the R-phase and T-phase inputs of the rectifier circuit, and the reactor is magnetically generated to generate inductance in both the normal mode and the common mode. It is characterized by being coupled, and electromagnetic noise can be reduced, and the device can be reduced in size, weight, and cost.

  ADVANTAGE OF THE INVENTION According to this invention, the converter apparatus which has a motor drive inverter control apparatus which is small and lightweight, and can remove a noise can be provided.

  According to a first aspect of the present invention, an AC power supply is input, a diode bridge, a rectifier circuit including a small-capacitance capacitor provided on the DC output side of the diode bridge, an inverter circuit for converting DC power into AC power, a motor, A reactor is connected to each of the R-phase and T-phase inputs of the rectifier circuit, and the reactor is magnetically coupled so as to generate inductance in both the normal mode and the common mode, Electromagnetic noise can be reduced, and the device can be reduced in size, weight, and cost.

2nd invention is a compressor which has the converter apparatus of 1st invention, It is characterized by the above-mentioned.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiment.

(Embodiment 1)
FIG. 1 is a circuit diagram of a converter device having a motor drive inverter control device according to a first embodiment of the present invention.

  The converter device having this motor drive inverter control device includes a single-phase AC power source 1 as an input, a rectifier circuit that receives the AC power source, an inverter circuit 2 that converts DC power into AC power, and a motor 3. The rectifier circuit is composed of a diode bridge 4 and a capacitor 5 having a small capacity of 0.4 μF or more and 100 μF or less connected to the DC output side of the diode bridge, and 2 mH or less for each of the R-phase and T-phase inputs of the rectifier circuit. The small capacity reactor 6 is connected. Here, the motor 2 is an induction motor, a DC brushless motor, a reluctance motor, or the like, and the type thereof is not limited.

  Next, the operation of the converter device having the motor drive inverter control device will be described. The AC voltage that is the output of the single-phase AC power supply 1 is rectified by a rectifier circuit, and a DC voltage is output to the inverter circuit 2 from the rectifier circuit. In order to reduce the size, weight and cost of the device, the capacitor 5 connected to the DC output side of the rectifier circuit and the reactor 6 connected to the R-phase and T-phase inputs of the rectifier circuit are reduced. In terms of capacity, when the load of the motor 3 connected to the output of the inverter circuit 2 is large, the voltage between the DC buses of the inverter circuit 2 may pulsate greatly with a period twice that of the AC power supply and may become zero.

  The converter device having the motor drive inverter control device of the present invention enables motor drive by inverter control even when the DC bus voltage of the inverter circuit 2 may become zero. Reactor 6 is connected to the R-phase and T-phase inputs of the rectifier circuit, and is magnetically coupled so as to generate inductance in both the normal mode and the common mode. Since inductance occurs in both the normal mode and the common mode, it is possible to obtain both the effect of a conventional power factor improving reactor and the effect of reducing electromagnetic noise.

  With the above configuration, electromagnetic noise can be reduced, and the reactor and the capacitor have a small capacity. Therefore, the apparatus can be reduced in size, weight, and cost.

  The converter device having the motor drive inverter control device of the present invention can be applied to a compressor equipped with an inverter circuit and an air conditioner equipped with the compressor.

  The converter device including the motor drive inverter control device of the present invention can be applied to a converter device having a motor drive inverter control device that drives a motor using an inverter circuit. For example, a refrigerator equipped with an inverter circuit, an electric washing machine, an electric dryer, a vacuum cleaner, a blower, a heat pump water heater, and the like. For any product, by reducing the size and weight of the motor drive device, the degree of freedom in product design is improved, and an inexpensive product can be provided.

Circuit diagram of converter device in Embodiment 1 of the present invention Circuit diagram of conventional converter device

Explanation of symbols

1 Single-phase AC power supply 2 Inverter circuit 3 Motor 4 Diode bridge 5 Capacitor 6 Reactor

Claims (2)

The rectifier circuit comprising: an AC power supply; a rectifier circuit comprising a diode bridge, a small-capacitance capacitor provided on the DC output side of the diode bridge; an inverter circuit for converting DC power to AC power; and a motor. A converter device, wherein a reactor is connected to each of the R-phase and T-phase inputs, and the reactor is magnetically coupled so as to generate inductance in both the normal mode and the common mode. A compressor equipped with the converter device according to claim 1.

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