KR102561123B1 - Conduction noise filtering circuit, inverting device and compressor - Google Patents

Abstract

A filter circuit for suppressing conductive noise is disclosed. A conductive noise filter circuit according to an embodiment of the present disclosure includes a first coil unit supplied with AC power, a second coil unit connected in series with the first coil unit, and a common signal from at least one of the first coil unit and the second coil unit. A current for canceling common mode noise is supplied between a power line connecting a first coil unit and a second coil unit in series based on a detection unit detecting mode noise and an output signal of the detection unit corresponding to the detected common mode noise. It includes a condenser part.

Description

Conductive noise filter circuit, inverter device and compressor {CONDUCTION NOISE FILTERING CIRCUIT, INVERTING DEVICE AND COMPRESSOR}

The present invention relates to a conductive noise filter circuit, an inverter device, and a compressor, and more particularly, to a conductive noise filter circuit having improved suppression performance against conductive noise, and an inverter device and a compressor having the same.

In modern times, technological development trends such as miniaturization, light weight, high speed, and low power consumption of electrical or electronic devices have made devices more precise, and devices are vulnerable to external interference. Accordingly, when designing a device, developers devise means for suppressing generation of noise and resistance to external electromagnetic interference.

As an example, an inverter device used to control a motor or the like includes a rectifying unit that converts a commercially available AC voltage into a DC voltage using a diode bridge or a switching element. And, the inverter device includes an inverter unit that converts the converted direct current voltage into an alternating current voltage by means of a switching element.

Such an inverter device generates conduction noise that affects other electronic devices via a power line due to a switching operation of a switching element. Conductive noise, a type of electromagnetic interference (EMI) noise, is normal mode noise (also called differential mode noise) that travels between power lines and between power lines and ground (earth). consists of common mode noise that conducts

Conventionally, conductive noise suppression circuits or filters have not sufficiently responded to conductive noise flowing through power lines, and feedback control for attenuating the noise has not been sufficiently performed. That is, since the level of conductive noise is regulated according to the standards of the Comite International Special des Perturbations Radioelectriques (CISPR), the International Special Committee on Radio Disorders, it is required to suppress conductive noise below a permissible value, but it is not sufficiently achieved. A problem existed.

The present invention was invented to solve the above problems, and an object of the present invention is to provide a conductive noise filter circuit having improved suppression performance against conductive noise, and an inverter device and a compressor having the same.

A conductive noise filter circuit according to an embodiment of the present disclosure for achieving the above object includes a first coil unit receiving AC power, a second coil unit disposed between the first coil unit and an output terminal, and the first coil unit. A detector for detecting common mode noise flowing through at least one of the coil unit and the second coil unit and a cancellation power for canceling the detected common mode noise are connected to a connection terminal to which the first coil unit and the second coil unit are commonly connected. It includes a capacitor unit to provide.

In this case, the first coil of the first coil part and the second coil of the second coil part may be wound around the same core.

Meanwhile, the first coil unit may include a plurality of first coils individually supplied to each phase of the AC power.

In this case, the second coil unit may include a plurality of second coils connected in series with each of the plurality of first coils.

Meanwhile, the detection unit may include a first detection coil magnetically coupled to at least one first coil of the first coil unit.

In this case, the detection unit may further include a second detection coil connected in series with the first detection coil and magnetically coupled to at least one second coil of the second coil unit.

Meanwhile, the conductive noise filter circuit may further include an amplification unit for amplifying an output signal of the detection unit and supplying the amplified signal to the capacitor unit.

In this case, the amplification unit may be configured as a current amplifier.

Meanwhile, an inverter device according to an embodiment of the present disclosure includes a rectifying unit for rectifying alternating current into direct current, a smoothing unit for smoothing the rectified direct current, and converting the smoothed direct current into alternating current by a switching operation of a plurality of switching elements. An inverter unit and a suppression unit for passing the AC input from the power supply to the rectification unit or transmitting the converted AC input from the inverter unit to a load, wherein the suppression unit includes a plurality of serially connected ACs supplied with the input AC. and a canceling power for canceling the common mode noise by using a signal detected from at least one of the plurality of coils, and providing a connection terminal connected in series with the plurality of coils.

On the other hand, a compressor for compressing a refrigerant according to an embodiment of the present disclosure includes a motor for providing power for compressing the refrigerant and an inverter device for converting AC power supplied into rated power for driving the motor, , The inverter device includes a plurality of coils connected in series receiving the AC power, detects common mode noise flowing through at least one of the plurality of coils, and uses a signal that detects the common mode noise to generate the common mode noise. and a filter providing an offset power for canceling mode noise to connection terminals connected in series to the plurality of coils.

The conductive noise filter circuit of the present disclosure according to various embodiments as described above can achieve the following effects.

According to one embodiment of the present disclosure, it is possible to provide a conductive noise filter circuit that sufficiently suppresses conductive noise.

In addition, according to another embodiment, since a signal for detecting common mode noise is large, response performance and tracking performance are high.

Further, according to another embodiment, since a plurality of coils are wound around one core, the conductive noise filter circuit can be miniaturized.

1 is a block diagram for explaining the configuration of an air conditioner to which an inverter device according to an embodiment of the present disclosure is applied;
Figure 2 is a block diagram for detailed description of the inverter device of Figure 1;
3 is a block diagram for explaining the suppression unit of FIG. 2 in more detail;
4 is a circuit diagram showing an inverter device according to a first embodiment of the present disclosure;
5 is an equivalent circuit diagram of a suppression unit and a rectification unit of the inverter device of FIG. 4 operating in a frequency band of noise to be suppressed;
6 is a circuit diagram of an inverter device in which a second coil unit is excluded from the inverter device of FIG. 4;
7 is an equivalent circuit diagram of a suppression unit and a rectification unit of the inverter device of FIG. 6 operating in a frequency band of noise to be suppressed;
8 is a graph for explaining the effect of suppressing common mode noise by the suppression unit of the inverter device according to the first embodiment;
9 is a circuit diagram showing an inverter device according to a second embodiment of the present disclosure;
10 is a circuit diagram showing an inverter device according to a third embodiment of the present disclosure, and
11 is a circuit diagram showing an inverter device according to a fourth embodiment of the present disclosure.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to users, operators, or conventions. Therefore, the definition should be made based on the contents throughout this specification.

1 is a block diagram for explaining the configuration of an air conditioner 90 to which an inverter device 100 according to an embodiment of the present disclosure is applied.

Referring to FIG. 1 , the air conditioner 90 includes an inverter device 100, a user input receiver 9, an indoor temperature sensor 10, a compressor 11, an indoor heat exchanger 12, and an indoor fan driver ( 13).

The air conditioner 90 receives AC power from the AC power source 200 . In one example, the AC power source may supply a commercial AC signal supplied to the home to the air conditioner 90 .

The inverter device 100 supplies power for driving the compressor 11 . Specifically, the inverter device 100 may supply electrical energy to the motor 300 of the compressor 11 to generate power for compressing the refrigerant.

The inverter device 100 includes a suppression unit 110, a rectification unit 120, a smoothing unit 130, an inverter unit 140, a converter unit 150, and a control unit 160. A more detailed description of the inverter device 100 will be described later with reference to FIG. 2 .

In addition, the inverter device 100 may convert AC power supplied from the AC power source 200 into rated power for driving the compressor 11 such as the motor 300. In order to control the motion of the motor 300, the rated power may have its frequency, magnitude, phase, etc. changed.

The user input receiver 9 receives a user's command to operate the air conditioner 90 . Specifically, the user input receiver 9 may be a power-on input, a timer input, and a desired temperature control input. Also, the user input receiving unit 9 may include a physical button or receive a command signal transmitted from a remote control device using infrared rays.

The room temperature sensing unit 10 senses the room temperature. Indoor temperature information from a temperature sensor included in the indoor temperature sensing unit 10 may be used as an input of control for maintaining a constant temperature.

The compressor 11 compresses the refrigerant. Specifically, the compressor 11 may suck in high-temperature, low-pressure refrigerant corresponding to room temperature, compress it to high-temperature, high-pressure, and discharge the compressed refrigerant to an outdoor unit according to the refrigerant cycle of the air conditioner.

A motor 300 included in the compressor 11 generates power. Specifically, the motor 300 may generate power for compressing the refrigerant by converting supplied electrical energy into dynamic energy. In one example, the motor 300 may generate and transmit rotational power to a piston, and compress the refrigerant sucked into the cylinder by the movement of the piston. In the example of FIG. 1 , the motor 300 of the compressor 11 is a load of the inverter device 100 .

The indoor heat exchanger 12 absorbs indoor heat. Specifically, the low-temperature refrigerant may expand by absorbing indoor heat in the indoor heat exchanger 12 .

The indoor fan driving unit 13 allows indoor air to pass through the indoor heat exchanger along the air flow path. Specifically, the indoor fan driving unit 13 may drive the fan to generate wind and allow indoor air to take away heat through the indoor heat exchanger 12 .

In the above, it has been exemplified that the inverter device 100 of the present disclosure is used to supply power to the motor 300 of the air conditioner 90, but is not limited thereto. The inverter device 100 may be used to supply power to a motor 300 used in a compressor of a refrigerator.

In the following description of the present disclosure, it will be described that the load of the inverter device 100 is the motor 300 . However, it is not limited thereto, and in actual implementation, the load may be a device other than the motor 300 .

FIG. 2 is a block diagram for detailed description of the inverter device of FIG. 1 .

Referring to FIG. 2 , the inverter device 100 includes a suppression unit 110, a rectification unit 120, a smoothing unit 130, an inverter unit 140, a converter unit 150, and a control unit 160.

The suppression unit 110 suppresses conductive noise. Specifically, the suppression unit 110 may suppress conductive noise (current) flowing along a plurality of power lines for supplying power to a load, that is, the motor 300 . The suppression unit 110 may be referred to as a filter in that it removes noise components of the current. A more detailed description of the restraining unit 110 will be described later with reference to FIG. 3 .

The rectifier 120 rectifies the AC supplied from the AC power source 200 into DC. The rectifier 120 may be a half-wave or full-wave rectifier circuit. The rectifier 120 may include a plurality of switches or a plurality of diodes.

The smoothing unit 130 smoothes the rectified direct current output from the rectifying unit 120 . The smoothing unit 130 may be composed of a smoothing capacitor that delays a change in voltage/current with respect to time.

The converter unit 150 converts the input DC voltage into a target voltage. Specifically, the converter unit 150 may convert the magnitude of the rectified DC voltage through a converting operation. For example, the converter unit 150 may boost or step down the magnitude of the input DC voltage to the operating voltage of the load. The converter unit 150 may include a plurality of switching elements controlled by the control unit 160 . The converter unit 150 may be implemented as a half-bridge or full-bridge converter using a bidirectional buck-boost converter or a transformer.

The inverter unit 140 converts the transformed direct current into alternating current and supplies it to the motor 300 . In detail, the inverter unit 140 may convert DC transformed into AC through an inverting operation. For example, the inverter unit 140 may convert the input direct current into a three-phase alternating current having an operating frequency of the load.

The controller 160 controls the converter unit 150 and the inverter unit 140 . Specifically, the control unit 160 outputs a signal for controlling the switching element included in the converter unit 150 to convert voltage, and controls the switching element included in the inverter unit 140 to invert DC to AC. A signal can be output to do so. The control unit 160 may output a PWM signal for controlling the switching operation of the switching element. The control unit 160 may control timing at which the plurality of switching elements are opened and closed by adjusting the duty ratio of the PWM signal. This control operation affects the power efficiency (power factor) for driving the motor 300 and the rotational speed (load amount).

FIG. 3 is a block diagram for explaining the suppression unit of FIG. 2 in more detail.

First, conductive noise will be described. Referring to FIG. 3 , conductive noise is divided into normal mode noise (long broken line) reciprocating between power lines, and common mode noise (dashed and dotted lines) in which current flows in the same direction along power lines.

Meanwhile, the suppression unit 110 includes a first coil unit 111 , a detection unit 112 , a condenser unit 113 , a second coil unit 114 , and an amplification unit 115 .

The first coil unit 111 receives AC power. And, the second coil unit 114 is disposed between the first coil unit 111 and the output terminal. The first coil unit 111 and the second coil unit 114 include a plurality of coils having impedance acting as resistance to AC. The first coil unit 111 and the second coil unit 114 are connected in series with each other.

Here, since the normal mode noise reciprocates in opposite directions while passing through the first coil unit 111 and the second coil unit 114, they cancel each other out.

However, since common mode noise flows in one direction toward the ground along the power line, electromagnetic interference (EMI) signals generated by the current are radiated into the air or leak unexpectedly. Noise that is radiated or leaked and transmitted to other devices may have a fatal effect on other devices, even if the size is very small.

The detector 112 detects common mode noise from at least one of the first coil unit 111 and the second coil unit 114 . In one embodiment, the detection unit 112 includes a detection coil magnetically coupled to the first coil included in the first coil unit 111 . The detection coil outputs a detection signal corresponding to common mode noise passing through the first coil unit 111 . In another embodiment, the detection unit 112 may include a plurality of detection coils, and may include a second detection coil magnetically coupled to the first coil and the second coil unit 114 . Here, the first detection coil and the second detection coil are serially connected to each other.

The amplifier 115 amplifies a signal corresponding to the common mode noise detected by the detector 112 . The amplified output signal is provided to a connection terminal connecting the first coil unit 111 and the second coil unit 114 through the capacitor unit 113 . The canceling current fed back to the common node of the first coil and the second coil connected in series cancels the common mode noise.

Hereinafter, the configuration of the inverter device 100 according to various embodiments applicable to the embodiments of FIGS. 1 to 4 will be described in detail. However, hereinafter, the converter unit 150 and the controller 160 will be omitted.

[First Embodiment]

4 is a circuit diagram illustrating an inverter device 100-1 according to a first embodiment of the present disclosure. In the example of FIG. 4 , the inverter device 100-1 receives AC from a three-phase, four-wire AC power source 200 including a neutral phase (N phase). Here, the 1st phase to the 3rd phase are expressed as R phase, S phase, and T phase. In addition, the power lines for supplying the R, S, T, and N phases from the AC power supply 200 are referred to as R-, S-, T-, and N-phase power lines. In the following description, when it is not necessary to distinguish between phases, it is referred to as a power supply line. In addition, in the following description, a common node to which the first coil unit 111 and the second coil unit 114 are connected in series is also referred to as a power supply line in the same way.

Here, it is exemplified that the inverter device 100-1 is connected to a motor 300 controlled by a three-phase alternating current as a load. For example, the motor 300 may be a three-phase AC motor including a DC brushless motor.

Referring to FIG. 4 , the inverter device 100-1 includes a suppression unit 110, a rectification unit 120, a smoothing unit 130, and an inverter unit 140.

The suppression unit 110 suppresses conductive noise. The rectifier 120 rectifies the AC supplied from the AC power source 200 into DC. The smoothing unit 130 smoothes the direct current output from the rectifying unit 120 . Then, the inverter unit 140 converts the smoothed direct current into three-phase alternating current and supplies it to the motor 300 . Redundant description of each configuration will be omitted.

Also, as shown in FIG. 4, some terminals of each configuration are grounded.

Each component of the inverter device 100-1 is connected in this order from the side of the AC power supply 200 to the suppression section 110, the rectification section 20, the smoothing section 30, and the inverter section 40. And, the motor 300 is connected to the inverter unit 40 .

The suppression unit 110 suppresses conductive noise. A more detailed description of the restraining unit 110 will be described later.

The rectifier 120 includes a diode bridge composed of, for example, six rectifier diodes D1 to D6. The six rectifier diodes D1 to D6 rectify the AC supplied from the AC power supply 200 into DC. When the rectifier diodes D1 to D6 are not distinguished, they are expressed as rectifier diode D.

The smoothing unit 30 includes a smoothing capacitor Cs. The smoothing capacitor Cs is connected between the high voltage side wiring (upper wiring in FIG. 1) of the direct current rectified by the rectifying section 120 and the reference voltage side wiring (lower wiring in FIG. 1) there is.

The inverter unit 140 includes six switching circuits SC1 to SC6 each having a switching element St and a feedback diode Df. In the following description, when it is not necessary to distinguish between the respective switching circuits SC1 to SC6, they are referred to as switching circuits SC.

And switching circuit SC1 of an upper arm and switching circuit SC2 of a lower arm are connected in series, and a connection point is connected to the terminal of the motor 300. The upper arm switching circuit SC1 and the lower arm switching circuit SC2 connected in series are provided between the high voltage side wiring and the reference voltage side wiring. The other switching circuits SC3 to SC6 are also the same.

On the other hand, the switching element St is a power such as a metal oxide silicon field effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), or a bipolar junction transistor (BJT). It may be implemented as a semiconductor switching device for use.

Here, the operation of the inverter device 100-1 according to the first embodiment is as follows.

A commercial AC power source 200 supplies an AC voltage to the rectifying unit 120 through a suppression unit 110 that suppresses conductive noise. The rectifying unit 120 rectifies the AC voltage supplied from the AC power source 200 to a DC voltage by means of the rectifier diodes D1 to D6 connected in a bridge shape. The smoothing unit 30 smoothes the pulsation of the DC voltage rectified in the rectifying unit 120 by the smoothing capacitor Cs. The inverter unit 40 supplies an AC voltage to the motor 300 by controlling the on/off of the switching element St in the switching circuit SC.

(Repressor 110)

Hereinafter, the restraining unit 110 will be described in more detail. Suppression section 110 is an active type conductive noise filter circuit that detects common mode noise and suppresses it through feedback. In addition, in the direction in which power is supplied, the AC power supply 200 side is referred to as the upstream side and the rectifying unit 20 side as the downstream side with respect to the suppression unit 110.

The suppression unit 110 includes a first coil unit 111, a detection coil L1A (112-1), a capacitor unit 113, a second coil unit 114, and an amplifier unit 115. The above configurations are connected to the first coil unit 111, the condenser unit 113, and the second coil unit 114 from the side of the AC power source 200 in this order. In addition, the first coil unit 111 is connected to the AC power supply 200, and the second coil unit 114 is connected to the rectifying unit 20. Also, the detection coil L1A (112-1) is provided to be magnetically coupled to the first coil unit 111.

The first coil section 111 includes coils (windings) L1R, L1S, L1T, and L1N connected in series for each power supply line of the R, S, T, and N phases. In the following, when it is not necessary to distinguish coils L1R, L1S, L1T, and L1N, they are referred to as coils L1.

Here, the coil refers to a wire wound in a spiral (loop) shape so as to form inductance.

These coils L1R, L1S, L1T, and L1N may be composed of a wire (wire) wound around one core (called an iron core) and constituting a part of a power supply line. The core may have a closed loop shape in which magnetic flux formed by currents of coils L1R, L1S, L1T, and L1N circulates along the core. For example, the core may be a toroidal core made of a magnetic material such as ferrite having an annular shape (donut shape) having a circular cross section. Further, the shape of the core may be not only an annular shape but also a polygonal frame shape such as a quadrangle or a triangle. In addition, the shape of the cross section may also be various shapes such as a square or a triangle.

Then, the coils L1R, L1S, L1T, and L1N are wound around one core so as to be adjacent to each other. Therefore, the coils L1R, L1S, L1T, and L1N are magnetically coupled (magnetically coupled) to each other. In addition, the polarities of the coils L1R, L1S, L1T, and L1N may be wound in the same direction, as shown by "●" in FIG. 1 .

And the detection coil L1A (112-1) is provided so that it may magnetically couple (magnetically couple) to the 1st coil part 111. In one example, the detection coil L1A (112-1) may be wound adjacent to the coils L1R, L1S, L1T, and L1N on one core. In another example, coils L1R, L1S, L1T, and L1N may be wound adjacent to each other on one core, and detection coil L1A (112-1) may be wound overlapping coils L1R, L1S, L1T, and L1N. In addition, the detection coil L1A 112-1 may be wound to have a polarity in a direction as shown by “●” in FIG. 1 .

One terminal of the detection coil L1A (112-1) is grounded. And the other terminal is connected to the amplification part 115 mentioned later.

The coils L1R, L1S, L1T, and L1N form part of the power line through which current flows from the AC power supply 200. Here, the coils L1R, L1S, L1T, and L1N may be composed of conductive wires (wires) having a thickness corresponding to the flowing current.

On the other hand, the detection coil L1A 112-1 detects a current of common mode noise (hereinafter referred to as common mode current) as will be described later. Accordingly, the detection coil L1A 112-1 is sufficient to be formed of a conducting wire (wire) having a thickness capable of detecting a common mode current.

Further, each of the coils L1R, L1S, L1T, and L1N may have the same inductance.

The common mode current is a high-frequency current that leaks to the ground through a stray capacitance of the motor 300 or the like due to switching of the switching element St of the inverter unit 40 . The common mode current flows in the same direction from the power line and the ground (earth) of the R phase, S phase, T phase, and N phase.

Coils L1R, L1S, L1T, and L1N, which are inductors, act as resistance to common mode current, which is a high-frequency signal. Therefore, the coils L1R, L1S, L1T, and L1N suppress (reduce) common mode noise. However, in the first coil unit 111, common mode noise cannot be completely eliminated.

When the common mode current flows through the coils L1R, L1S, L1T and L1N, a current proportional to the common mode current is induced in the detection coil L1A (112-1) through the core.

That is, the first coil unit 111 and the detection coil L1A 112-1 function as a current transformer and constitute a detection transformer that detects a common mode current.

In addition, the normal mode current flows in opposite directions between the power lines. Accordingly, the coils L1R, L1S, L1T, and L1N wound around the toroidal core function to mutually cancel flowing normal mode noise.

The capacitor unit 113 includes capacitors C1R, C1S, C1T, and C1N. Terminals of each of the capacitors C1R, C1S, C1T, and C1N are connected to respective power supply lines of the R phase, S phase, T phase, and N phase. The other terminal of each of the capacitors C1R, C1S, C1T, and C1N is commonly connected to an output terminal of an amplifying section 115 described later. In this case, the output of the operational amplifier 116 constituting the amplification section 115 (the current that cancels out the common mode noise current) passes through the capacitors C1R, C1S, C1T, and C1N, and passes through the R, S, and T phases. , N phases are connected in common to each power line. Here, when capacitors C1R, C1S, C1T, and C1N are not distinguished, they are expressed as capacitor C1.

Meanwhile, capacitors C1R, C1S, C1T, and C1N may have the same capacitance.

Capacitors C1R, C1S, C1T, and C1N are disposed between the power lines of the R, S, T, and N phases. For example, capacitor C1R and capacitor C1S connected in series are disposed between the R-phase power supply line and the S-phase power supply line. Therefore, these capacitors C1R, C1S, C1T, and C1N function to mutually cancel normal mode noise flowing through the power lines of the R, S, T, and N phases.

The second coil unit 114 includes coils L2R, L2S, L2T, and L2N connected in series to power lines of R, S, T, and N phases, respectively. These coils L2R, L2S, L2T, and L2N are conducting wires (wires) constituting a part of the power supply line, and, like the configuration of the first coil portion 111, are wound around another core. Therefore, the coils L2R, L2S, L2T, and L2N are magnetically coupled (magnetically coupled) to each other. In addition, the coils L2R, L2S, L2T, and L2N are wound so as to have a polarity indicated by "?" in FIG. In the following, when it is not necessary to distinguish the coils L2R, L2S, L2T, and L2N, they are referred to as coil L2.

Also, the coils L2R, L2S, L2T, and L2N may have the same inductance.

The inductance coils L2R, L2S, L2T, and L2N, like the first coil unit 111, act as resistance to the common mode current. Therefore, the coils L2R, L2S, L2T, and L2N suppress (reduce) common mode noise. However, similar to the first coil unit 111, even the second coil unit 114 does not remove all common mode noise.

Further, the coils L2R, L2S, L2T, and L2N wound around the core function to mutually eliminate normal mode noise.

The amplifier 115 includes an operational amplifier (Op Amp) 116, resistors R1, R2, and R3, and capacitors C2 and C3. The other terminal of the detection coil L1A (112-1) is grounded via the resistor R1.

The non-grounded terminal of the resistor R1 is the non-inverting input node of the operational amplifier 116 (represented as “+” in FIG. 1 and hereinafter referred to as the non-inverting input node (+)) ) is connected to.

Capacitor C2 is a feedback capacitor, resistor R3 is a feedback resistor, and these two are connected in parallel with each other. Then, one terminal of each of the capacitor C2 and the resistor R3 is connected to the inverting input terminal of the operational amplifier 116 (indicated by "-" in Fig. 1 and referred to as the inverting input terminal (-) in the following). . On the other hand, the other terminal of each of the capacitor C2 and the resistor R3 is connected to the output terminal of the operational amplifier 116. Then, the inverting input terminal (-) of the operational amplifier 116 is grounded through the resistor R2. In addition, the capacitor C3 for adjusting the phase is disposed between the output terminal of the operational amplifier 116 and the driving power supply terminal (not shown) of the operational amplifier 116. Meanwhile, the operational amplifier 116 may be implemented as a current amplifier.

Hereinafter, the function and operation of the restraining unit 110 will be described in detail.

First, in the first coil section 111, the detection coil L1A (112-1) detects common mode noise (common mode current) in the R-phase, S-phase, T-phase, and N-phase power supply lines. Next, the operational amplifier 116 of the amplifier 115 amplifies the current generated in the detection coil L1A (112-1) by the detected common mode current, and through the capacitor unit 113, R phase, S phase, It is supplied (overlapped) to the power lines of T phase and N phase respectively. Here, the operational amplifier 116 amplifies the current induced by the common mode current so as to eliminate (cancel) the common mode noise. Therefore, common mode noise in the R-phase, S-phase, T-phase, and N-phase power lines is suppressed.

In addition, the capacitors C1R, C1S, C1T, and C1N of the capacitor unit 113 are set so that currents corresponding to the common mode noise levels of the corresponding respective R-phase, S-phase, T-phase, and N-phase power lines are overlapped.

In the above description, the amplifier 115 has been exemplified as amplifying a current corresponding to the sensed common mode current, but may be implemented to amplify a voltage (common mode voltage) converted from the common mode current. That is, the amplifier 115 may be configured to receive voltage and output current.

As described above, the suppression unit 110 suppresses normal mode noise and common mode noise, which are conductive noises.

Next, the function of the second coil unit 114 will be described.

5 is an equivalent circuit diagram of the suppression unit 110 and the rectification unit 120 of the inverter device 100-1 of FIG. 4 operating in a frequency band of noise to be suppressed. Fig. 5(a) is an AC equivalent circuit corresponding to Fig. 1, and Fig. 5(b) is an AC equivalent circuit viewed from the output terminal of the operational amplifier 116 in the amplifying section 115.

Common mode noise is a high-frequency signal (alternating current). Therefore, the coils L1 and L2 function as resistances in an alternating manner, and the capacitor C1 short circuits in an alternating manner. In addition, the R phase, S phase, T phase, and N phase of the AC power supply 200 are short-circuited in terms of AC. Then, the current diode D of the rectifying section 20 is short-circuited (shorted) in an alternating manner.

Accordingly, in FIGS. 5(a) and (b), coils L1 and L2 are represented by symbols of resistance, and capacitor C1 is represented by lines. In addition, the rectifying diode D of the rectifying unit 120 is expressed as a diode symbol.

As shown in Fig. 5(a), a detection coil L1A (112-1) and a resistor R1 are connected in parallel to the non-inverting input terminal (+) of the operational amplifier 116 in the amplifier 115. The detection coil L1A (112-1) functions as a resistance in an alternating manner. Therefore, the impedance with respect to the non-inverting input terminal (+) of the operational amplifier 116 is formed high. Similarly, the voltage of the signal corresponding to the common mode current detected by the first coil unit 111 is high. This makes it easier for the voltage corresponding to the common mode current to be input to the operational amplifier 116 and easier to follow the change in the common mode current, so that common mode noise can be precisely suppressed.

Also, as a method of detecting common mode noise, detection through a plurality of capacitors identical to those of the capacitor unit 113 can be considered. In this case, the 1st coil part 111 in FIG.5 (a) becomes the same structure as the capacitor|condenser part 113. Since the capacitor is short-circuited in an alternating manner, the impedance to the non-inverting input terminal (+) of the operational amplifier 116 is lowered, and the voltage corresponding to the common mode current is lowered. Therefore, it is difficult for a voltage corresponding to the common mode current to be input to the operational amplifier 116, and it is difficult to keep up with changes in the common mode current.

Thus, in the suppression unit 110 according to the first embodiment, the detection coil L1A (112-1) performs detection of common mode noise (common mode current). Thanks to this, the impedance to the input terminal (non-inverting input terminal (+)) of the operational amplifier 116 can be set high.

On the other hand, as shown in Fig. 5(b), the output terminal of the operational amplifier 116 in the amplifying section 115 is grounded through the coils L1R, L1S, L1T, and L1N of the first coil section 111, respectively. do. Further, the output terminal of the operational amplifier 116 is grounded through a series connection between the coils L2R, L2S and L2T of the second coil unit 114 and the rectifier diodes D1 to D6 of the rectifier unit 120, respectively. Also, the coil L2N is grounded without going through the rectifying diode D.

At this time, the rectifying diodes D1 to D6 are short-circuited (shorted) AC. However, the coils L1R, L1S, L1T, and L1N and the coils L2R, L2S, L2T, and L2N function as resistances in an alternating current. Thus, the load of operational amplifier 116 has a high impedance. Therefore, the output terminal of the operational amplifier 116 can output a current that eliminates (cancels) the common mode noise with a high voltage.

As an example, the output voltage of the operational amplifier 116 required to suppress common mode noise is about ±20V. At this time, the output current is about ±0.3A.

Such an output voltage and output current can be corresponded to using a well-known operational amplifier (op amp).

Also, it is conceivable to carry out current or voltage that eliminates (cancels) common mode noise through an inductor connected in series to the power supply line instead of the capacitor C1. At this time, when a low-impedance driving circuit (for example, a push-pull type transistor circuit) supplies current to the inductor, the inductance of the inductor varies, and the current flowing through the power line may vary.

In conclusion, the suppression unit 110 according to the first embodiment of the present disclosure includes coil L1 of the first coil unit 111 and coil L2 of the second coil unit 114 connected to the operational amplifier 116 as a load. This parallel connection is made. Therefore, the amplifier 115 has a high impedance load. Due to this, the influence on the signal current flowing through the power supply line can be suppressed.

FIG. 6 is a circuit diagram of the inverter device 100' in which the second coil unit 114 is excluded from the inverter device 100-1 of FIG. 4 .

Referring to FIG. 6 , in the inverter device 100', the second coil unit 114 included in the inverter device 100-1 of FIG. 4 is omitted. In addition, the inverter device 100' does not include an N-phase power supply line. Therefore, the N-phase power line and the like are indicated by broken lines. That is, AC is supplied to the inverter device 100' by the three-phase, three-wire AC power supply 200. Since other configurations are the same as those of the inverter device 100-1 according to the first embodiment shown in FIG. 4, descriptions thereof are omitted.

FIG. 7 is an equivalent circuit diagram of the suppression unit 110 and the rectification unit 120 of the inverter device 100' of FIG. 6 operating in a frequency band of noise to be suppressed. Fig. 7(a) is an AC equivalent circuit corresponding to Fig. 6, and Fig. 6(b) is an AC equivalent circuit viewed from the output terminal of the operational amplifier 116 of the amplifier section 115.

As in Fig. 5(a) and (b), the coil L1 functions as a resistance in an alternating manner, and the capacitor C1 is short-circuited in an alternating manner. In addition, the R phase, S phase, T phase, and N phase of the AC power supply 200 are short-circuited in terms of AC. Then, the rectifying diode D of the rectifying section 120 is short-circuited (shorted) in an AC manner.

The non-inverting input terminal (+) of the operational amplifier 116 in the amplifying section 115 is the same as that of the inverter device 100-1 shown in Figs. 4 and 5(a). That is, the impedance to the non-inverting input terminal (+) of the operational amplifier 116 is high. Accordingly, the voltage corresponding to the common mode current detected in the first coil unit 111 is high, and is easily input to the operational amplifier 116 of the amplifier unit 115.

On the other hand, as shown in Fig. 5(b), the output terminal of the operational amplifier 116 in the amplifying section 115 is grounded via the current diodes D1 to D6 of the rectifying section 120. At this time, the rectifier diodes D1 to D6 are connected to each other in the direction in which the current flows with respect to the ground. Therefore, if the voltage from the output terminal of the operational amplifier 116 is either positive or negative, it is grounded from any one of the rectifier diodes D1 to D6 in the forward direction.

For example, in the case of a silicon diode, the forward voltage is low, and the voltage is about 1.5V even when a current of 30A flows.

That is, if it is desired to supply a current for eliminating the common mode current through the capacitor unit 113, it is necessary to supply a large current at a low voltage. However, in the widely used operational amplifier 116, it is difficult to supply a current of 30 A at a voltage of, for example, 1.5 V.

If there is an N-phase power supply line, the output terminal of the operational amplifier 116 is grounded as shown by the dotted line in FIG. 4(b). For this reason, in the inverter device 110 to which the first embodiment is not applied, the N-phase power line cannot be used.

As described above, in the inverter device 100-1 according to the first embodiment, since the suppression unit 110 includes the first coil unit 111 and the second coil unit 114, the operational amplifier ( 116) has high impedance seen from the input terminal (non-inverting input terminal (+)). Because of this, it is easy to follow for fluctuations in the detected common mode current. Therefore, common mode noise can be precisely suppressed. Further, the impedance viewed from the output terminal of the operational amplifier 116 is high. This feature has the advantage of using a general operational amplifier 116 even if it is not a high-end product.

That is, conductive noise including common mode noise can be easily suppressed.

8 is a graph for explaining an effect of suppressing common mode noise by the suppressing unit 110 of the inverter device 100-1 according to the first embodiment.

Referring to FIG. 8, the vertical axis is the noise terminal voltage (dB (μV)), which is the voltage drop across the resistor for measuring noise of the line impedance stabilization network (LISN). The horizontal axis is frequency (MHz). In addition, the graph of FIG. 8 also shows the allowable value 810 set by the International Special Committee on Radio Interference CISPR.

In the inverter device 100-1 according to the first embodiment, the amplifier 115 operates when driving power for driving the operational amplifier 116 is supplied (on), and operates when driving power is not supplied (off). ) it does not work. The graph of FIG. 5 shows both an on state (amplifier unit on 830) and an off state (amplifier unit off 820) of the operational amplifier 116.

When the amplification unit is turned on (830), the operational amplifier 116 operates, and the common mode current sensed by the coil L1A is amplified. Therefore, the current that cancels out the common mode current is supplied (overlapped) from the capacitor section 113 to the respective power supply lines of the R, S, T, and N phases. That is, when the amplification unit is on (830), the suppression unit 110 is operating.

Meanwhile, when the amplification unit is off 820, the operational amplifier 116 does not operate, and the common mode current sensed by the coil L1A is not amplified. Therefore, the current that cancels the common mode current is not supplied (overlapped) from the capacitor section 113 to the respective power supply lines of the R, S, T, and N phases. That is, when the amplification unit is off 820, the suppression unit 110 is not operating.

Comparing the amplification part on 830 and the amplification part off 820, in the amplification part off 820, the noise terminal voltage exceeds the allowable value in the frequency band of 0.5 MHz or less. However, in the amplifying unit ON (830), the noise terminal voltage is below the allowable value.

In the inverter device 100-1 according to the first embodiment, the suppression unit 110 sufficiently suppresses common mode noise, that is, conductive noise.

In addition, the inverter device 100 according to the first embodiment also suppresses conductive noise along the N-phase power supply line.

In addition, if the operational amplifier 116 of the amplification section 115 in the suppression section 110 is implemented as a current amplifier, the current that cancels out (cancels) the common mode current can be easily controlled.

In the inverter device 100-1 according to the first embodiment described above, the detection coil L1A 112-1 is magnetically coupled to the first coil unit 111. However, even if the detection coil L1A (112-1) is magnetically coupled to the second coil unit 114, it operates in the same way.

[Second Embodiment]

The inverter device 100-1 according to the first embodiment shown in FIG. 4 receives AC from a three-phase, four-wire AC power source 200. The inverter device 100-2 according to the second embodiment receives AC from a three-phase, three-wire AC power supply 200.

9 is a circuit diagram illustrating an inverter device 100-2 according to a second embodiment of the present disclosure.

Referring to FIG. 9 , an inverter device 100-2 according to the second embodiment does not include an N-phase power supply line in the inverter device 100-1 of FIG. 4 . That is, the inverter device 100-2 includes a power line corresponding to the three-phase, three-wire AC power supply 200. Since other configurations are the same as those of the inverter device 100-1 shown in Fig. 4, the same reference numerals are given and redundant descriptions are omitted.

Even in the inverter device 100 using the three-phase, three-wire AC power supply 200, conductive noise is suppressed by the suppression unit 110 as described in the first embodiment.

[Third Embodiment]

In the inverter device 100-1 according to the first embodiment and the inverter device 100-2 according to the second embodiment, AC is supplied from the three-phase AC power supply 200. In contrast, the inverter device 100 according to the third embodiment receives AC from the single-phase, two-wire AC power supply 200 .

10 is a circuit diagram showing an inverter device 100-3 according to a third embodiment of the present disclosure.

Referring to FIG. 10, in the inverter device 100-3 according to the third embodiment, in the inverter device 100-1 of FIG. 1, R phase and S phase are replaced with X phase and Y phase, and T phase, N-phase alternating current is not supplied. And the rectifying part 120 is provided with four rectifying diodes D1-D4. That is, the inverter device 100-3 includes a power line corresponding to the single-phase two-wire AC power supply 200. Since other configurations are the same as those of the inverter device 100-1 according to the first embodiment shown in FIG. 4, the same reference numerals are given and descriptions are omitted.

Even in the inverter device 100-3 using the single-phase, two-wire AC power supply 200, conductive noise is suppressed by the suppression unit 110, as in the inverter device 100-1 of the first embodiment described above.

[Fourth Embodiment]

The inverter device 100 - 1 according to the first embodiment includes a detection coil L1A 112 - 1 magnetically coupled to the first coil unit 111 . The inverter device 100 - 4 according to the fourth embodiment further includes a second detection coil L2A 112 - 2 magnetically coupled to the second coil unit 114 of the restraining unit 110 . The detection coil L2A 112-2 also detects the common mode current.

11 is a circuit diagram showing an inverter device 100-4 according to a fourth embodiment of the present disclosure.

Referring to FIG. 11 , the inverter device 100 - 4 includes a second detection coil L2A 112 - 2 that detects a common mode current with respect to the second coil unit 114 . And one terminal of the 1st detection coil L1A (112-1) is connected to one terminal of the 2nd detection coil L2A (112-2) without being grounded. And the other terminal of the 2nd detection coil L2A (112-2) is grounded.

Since other configurations are the same as those of the inverter device 100-1 according to the first embodiment shown in FIG. 4, the same reference numerals are given and descriptions are omitted.

In this way, the plurality of detection coils L1A 112 and L2A 112-2 can form a larger impedance and output a larger detection signal for the common mode current. Therefore, the detector 112 Changes in common mode current can be better followed, and common mode noise can be suppressed more accurately.

In one example, the coil L1R of the first coil unit 111 and the coil L2R of the second coil unit 114 may be formed of a tapped wire (wire) wound around one core. In this case, one end of the conducting wire (wire) is connected to the power line of the R phase on the AC power supply 200 side, and the other end of the conducting wire (wire) is connected to the power line of the R phase on the load side (the downstream side including the rectifier 120). connected A capacitor C1R is connected to the tap. The other coils L1S, L1T, L1N and coils L2S, L2T, L2N are constructed in the same way. Similarly, the first detection coil L1A (112-1) and the second detection coil L2A (112-2) may be wound around one core.

In this way, the first coil unit 111 and the second coil unit 114 can be configured as a single member.

As another example, coils L1R, L1S, L1T, L1N and detection coil L1A (112) may be wound on one core, and coils L2R, L2S, L2T, L2N and detection coil L2A (116) may be wound on another core. there is. In this case, it is possible to make the parts in which the first coil part 111 and the detection coil L1A (112) are combined and the parts in which the second coil part 114 and the detection coil L2A (116) are combined are the same. Therefore, the manufacturing and management of the parts are facilitated.

In addition, the additional detection coil L2A (112-2) as described above is magnetically coupled to the second coil unit 114 of the suppression unit 110, the inverter device (100-2, 100) according to the second or third embodiment. -3) can be further included.

In the inverter device 100 according to the first to fourth embodiments, the restraining unit 110 is disposed between the AC power source 200 and the rectifying unit 20, but is not limited thereto. The restraining unit 110 may be disposed between the inverter unit 40 and the motor 300 that is a load of the inverter device 100 . That is, it is sufficient if the restraining unit 110 is placed on a power supply line that supplies alternating current.

The inverter devices 100-1, 100-2, 100-3, 100-4, and 100-5 of the first to fourth embodiments described above are not limited to the described configuration, and as an example, an electronic member (resistor, capacitor) , coil, etc.) or a circuit may be further included.

Meanwhile, in the above-described embodiments, the suppression unit 110 has been described as suppressing conductive noise of the inverter device 100, but is not limited thereto. The suppression unit 110 for suppressing conductive noise may be applied to any device that generates conductive noise other than the inverter device 100 .

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the above-described examples, and ordinary knowledge in the art to which the present invention pertains without departing from the gist of the present invention claimed in the claims Anyone who has it can implement various modifications, of course, and such changes are within the scope of the claims.

100, 100-1, 100', 100-2, 100-3, 100-4, 100-5: inverter unit
110: suppression unit 111: first coil unit
112: detection unit 112-1: first detection coil
112-2: second detection coil 113: capacitor unit
114: second coil unit 115: amplification unit
116: operational amplifier 120: rectifier
130: smoothing unit 140: inverter unit
150: converter unit 160: control unit
200: AC power 300: motor
C1, C1R, C1S, C1T, C1N, C1X, C1Y, C2, C3: Condenser
Cs: smoothing capacitor
D, D1 to D6: rectifier diode
Df: feedback diode
L1, L1R, L1S, L1T, L1N, L2, L2R, L2S, L2T, L2N: coil
L1A, L2A: Detection coils R1 to R3: Resistance
SC, SC1 to SC6: switching circuit St: switching element

Claims (10)

In the inverter device for converting AC power into rectified power for driving a motor,
A first coil unit connected to AC power;
a second coil unit having one end connected to the first coil unit and the other end connected to a rectifying unit including a plurality of diodes;
a first inductor coupled to the first coil unit and detecting a first common mode current flowing through the first coil unit;
a second inductor coupled to the second coil unit, having one end connected to the other end of the first inductor, and detecting a second common mode current flowing through the second coil unit having the other end connected to ground;
an amplifier that amplifies the current received from the first inductor and the second inductor; and
A current amplified by the amplifier is received, and an offset power corresponding to the amplified current is applied to the first coil unit and the second coil to cancel the detected first common mode current and second common mode current. A capacitor unit provided to the connection terminal to which the unit is connected in common; includes,
The other end of the first inductor is connected to the other end of the first resistor having one end grounded and to the input terminal of the amplifier. According to claim 1,
The inverter device wherein the first coil of the first coil unit and the second coil of the second coil unit are wound on the same core. According to claim 1,
The first coil part,
Including a plurality of first coils individually supplied to each phase of the AC power, the inverter device. According to claim 3,
The second coil part,
Including a plurality of second coils connected in series with each of the plurality of first coils, the inverter device. According to claim 1,
the amplifier,
Inverter device, consisting of a current amplifier. In the air conditioner,
Compressor including motor; and
Including; an inverter device that converts AC power into rectified power for driving the motor and delivers driving power to the compressor;
The inverter device,
A first coil unit connected to AC power;
a second coil unit having one end connected to the first coil unit and the other end connected to a rectifying unit including a plurality of diodes;
a first inductor coupled to the first coil unit and detecting a first common mode current flowing through the first coil unit;
a second inductor coupled to the second coil unit, having one end connected to the other end of the first inductor, and detecting a second common mode current flowing through the second coil unit having the other end connected to ground;
an amplifier that amplifies the current received from the first inductor and the second inductor; and
A current amplified by the amplifier is received, and an offset power corresponding to the amplified current is applied to the first coil unit and the second coil to cancel the detected first common mode current and second common mode current. Including; a condenser unit provided to a connection terminal to which the unit is connected in common;
The other end of the first inductor is connected to the other end of the first resistor having one end grounded and to the input terminal of the amplifier. In the refrigeration system,
Compressor including motor; and
Including; an inverter device that converts AC power into rectified power for driving the motor and delivers driving power to the compressor;
The inverter device,
A first coil unit connected to AC power;
a second coil unit having one end connected to the first coil unit and the other end connected to a rectifying unit including a plurality of diodes;
a first inductor coupled to the first coil unit and detecting a first common mode current flowing through the first coil unit;
a second inductor coupled to the second coil unit, having one end connected to the other end of the first inductor, and detecting a second common mode current flowing through the second coil unit having the other end connected to ground;
an amplifier that amplifies the current received from the first inductor and the second inductor; and
A current amplified by the amplifier is received, and an offset power corresponding to the amplified current is applied to the first coil unit and the second coil to cancel the detected first common mode current and second common mode current. A capacitor unit provided to the connection terminal to which the unit is connected in common; includes,
The other end of the first inductor is connected to the other end of the first resistor having one end grounded and the input terminal of the amplifier.
delete delete delete

Images