WO2021166018A1

WO2021166018A1 - Noise suppression device

Info

Publication number: WO2021166018A1
Application number: PCT/JP2020/005972
Authority: WO
Inventors: 泰章古庄; 良太朝倉; 護神蔵
Original assignee: 三菱電機株式会社
Priority date: 2020-02-17
Filing date: 2020-02-17
Publication date: 2021-08-26
Also published as: JPWO2021166018A1; JP6906731B1; DE112020006741T5

Abstract

A noise suppression device (20) disposed between an AC power supply and a device to be controlled and transmitting a signal to the device to be controlled is provided with: a detection circuit (30) for detecting a specific signal; a waveform signal forming circuit (40) for forming a predetermined waveform signal from the specific signal detected by the detection circuit (30); a signal transmitter (50) for transmitting the waveform signal formed by the waveform signal forming circuit (40) to the device to be controlled; a state detector (60) for detecting a state signal indicating the state of the device to be controlled or the waveform signal forming circuit (40); and a gain adjuster (70) built in the waveform signal forming circuit (40) and adjusting the gain of the waveform signal in accordance with any one of the state signals detected by the state detector (60). The waveform signal adjusted by the gain adjuster (70) is transmitted to the device to be controlled.

Description

Noise suppression device

This application relates to a noise suppression device.

A noise suppression device represented by a conventional noise filter includes a choke coil connected in series with a noise path and noise in order to reduce high-frequency noise generated in a power supply line wired between the inverter device and the system. It is composed of a combination of capacitors and the like connected in parallel to the path.

Regarding this noise suppression device, in order to reduce the size or weight while enhancing the noise reduction effect, the high frequency noise detecting means, the high frequency amplifying means for amplifying the detected high frequency noise, and the amplified high frequency noise are reversed. There is an active noise canceling technology that reduces high-frequency noise by using an injection transformer provided with an auxiliary winding that electromagnetically injects into the power supply line in phase.

Specifically, a common mode current detecting means (for example, zero-phase CT (Current Transformer), etc.), a compensation calculation unit, a current generating means, and a common mode transformer are provided between the three-phase power supply line and the power converter, and three phases are provided. In some cases, the common mode current of the power supply line is detected and the canceling current calculated by the compensation calculation unit is injected into the auxiliary winding of the common mode transformer (see, for example, Patent Document 1).

Further, a common mode voltage detecting means using a capacitor, a voltage generating means, and a common mode transformer are provided between the three-phase power supply line and the power conversion device, and the common mode voltage of the power conversion device is detected and offset by the compensation calculation unit. In some cases, the compensation voltage for is calculated and injected into the auxiliary winding of the common mode transformer (see, for example, Patent Document 2).

Japanese Patent No. 4238638 Japanese Patent No. 5263663

In a noise suppression device using an active element that transmits a compensation voltage or a canceling current via the common mode transformer described in Patent Document 1 or Patent Document 2, the magnetic flux saturation of the transformer core or the protection of the noise suppression device is achieved. It became a limitation and hindered the miniaturization or cost reduction of the device.

Specifically, when an instantaneous overload or an instantaneous imbalance occurs in the power converter, there is a problem that the normal component magnetic flux in the transformer core temporarily increases due to a temporary increase in the normal mode current. .. Further, there is a problem that the transformer core becomes large in size in order to avoid magnetic saturation of the transformer core.

This application discloses a technique for solving the above-mentioned problems, and aims to realize a noise suppression device using an active element in a small size and at low cost.

The noise suppression device disclosed in the present application is
A noise suppression device that is arranged between an AC power supply and a controlled device and transmits a signal to the controlled device.
A detection circuit that detects a specific signal and
A waveform signal forming circuit that forms a predetermined waveform signal from a specific signal detected by this detection circuit, and
A signal transmitter that transmits the waveform signal formed by the waveform signal forming circuit to the controlled device, and
A state detector that detects a state signal representing the state of the controlled device or the waveform signal forming circuit, and
A gain adjuster built in the waveform signal forming circuit and adjusting the gain of the waveform signal according to any one of the state signals detected by the state detector.
With
It is characterized in that a waveform signal adjusted by the gain adjuster is transmitted to the controlled device.

According to the noise suppression device disclosed in the present application, a noise suppression device using an active element can be realized in a small size and at low cost.

It is a schematic diagram which shows the circuit of the power conversion system to which the noise suppression device which concerns on this application is applied. It is a figure which shows an example of the circuit of a typical two-level three-phase inverter. It is a figure which shows the common mode equivalent circuit of the power conversion system to which the noise suppression device which concerns on this application is applied. It is a figure for demonstrating the circuit of the noise suppression apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the structural example of the detection circuit which concerns on

Embodiment

1, 2, 3, 4, 5. It is a figure which shows an example of the waveform signal formation circuit which concerns on

Embodiment

1, 2, 3, 4, 5. It is a figure which shows the structural example of the signal transmitter which concerns on

Embodiment

1, 2, 3, 4, 5. It is a figure which shows the structural example of the gain adjuster which concerns on

Embodiment

1, 2, 3, 4, and 5. It is a figure which shows an example of the operation of the structural example of the gain adjuster which concerns on

Embodiment

1, 2, 3, 4, and 5. It is a circuit diagram which shows an example of the noise suppression apparatus which concerns on Embodiment 2. FIG. It is a figure which shows the structural example of the state detector which concerns on

Embodiment

1, 2, 3, 4, and 5. It is a circuit diagram which shows an example of the noise suppression apparatus which concerns on Embodiment 4. FIG. It is a figure which shows an example of the hardware which concerns on the signal processing of the noise suppression apparatus of this application.

The present application relates to a noise suppression device that reduces high-frequency noise generated in a power conversion device or the like that is connected to an AC power supply and outputs an arbitrary AC voltage. Hereinafter, this noise suppression device will be described with reference to the drawings. ..

Further, in the following drawings, those having the same reference numerals are the same or equivalent thereto, and are common to the whole texts of the embodiments described below. The form of the component represented in the full text of the specification is merely an example and is not limited to the form described in the specification. In particular, the combination of components is not limited to the combination in each embodiment, and the components described in other embodiments can be applied to another embodiment.

Embodiment 1.
FIG. 1 is a schematic diagram showing a circuit of a power conversion system 100 to which the noise suppression device according to the present application is applied. The AC power supply 1, the power conversion device 80 which is a controlled device, the load 90 thereof, the power supply line 2 between the AC power supply and the power conversion device connecting the AC power supply 1 and the power conversion device 80, and the power conversion device. A power conversion system 100 including a noise filter 10 provided to suppress noise generated by the operation of 80 and flowing out to the AC power supply 1 and inserted into a power supply line between the AC power supply 1 and the power conversion device 80. It is shown.

As an example of the power conversion device 80, FIG. 2 shows a circuit diagram of a typical two-level three-phase inverter. As the load, for example, an electric motor or the like is connected. The combination of the semiconductor switch 82a and the semiconductor switch 82b constitutes the U-phase upper / lower arm 83, and similarly, the combination of the semiconductor switch 84a and the semiconductor switch 84b constitutes the V-phase upper / lower arm 85, and the combination of the semiconductor switch 86a and the semiconductor switch 86b. Consists of the W-phase upper and lower arms 87. These three types of upper and

lower arms

83, 85, and 87 perform switching operations to output AC power to the inverter output end 88. At this time, since the output potential of each arm of the U phase, the V phase, and the W phase takes either the positive voltage or the negative voltage of the inverter DC power supply 89, the common mode voltage Vcm of the inverter is a constant value other than zero. , (Vu + Vv + Vw) / 3.

FIG. 3 is a common mode equivalent circuit of the above-mentioned power conversion system 100. The common mode voltage is applied to the grounded capacitor 11 included in the noise filter 10, the ground parasitic capacitance 81 of the power conversion device 80, the ground parasitic capacitance 91 of the load 90, and the common mode loop via the ground wire 3, and the common mode is applied. Current flows. The arrow shown between the AC power supply 1 and the noise filter 10 indicates the generated common mode noise 4.

FIG. 4 is a circuit of the noise suppression device 20 according to the first embodiment. The noise suppression device 20 (see the dotted line frame inside the figure) is a part of the noise filter 10 (see the dotted line frame outside the figure) for the purpose of reducing the common mode noise of the power conversion system. Or make up everything. In the present embodiment, the noise filter 10 is composed of the grounding capacitor 11 and the noise suppression device 20.

The noise suppression device 20 is formed by a detection circuit 30 that detects a specific signal such as noise, and a waveform signal forming circuit 40 that forms a desired waveform signal based on the components detected from the detection circuit 30. A signal transmitter including an injection transformer 50 that transmits a waveform signal to a common mode, a state detector 60 that detects the operating state of the power converter 80 or the waveform signal forming circuit 40 itself, and a state detector 60 that detects the detected signal. It is composed of a gain adjuster 70 that adjusts the gain by a predetermined amount or a predetermined timing.

FIG. 5 is a configuration example of the detection circuit 30 according to the first, second, third, fourth, and fifth embodiments, and shows a case where the detection circuit is configured by a common mode transformer. The detection transformer is inserted into the RST phase power line between the AC power supply 1 and the power conversion device 80 which is the controlled device, and the R phase winding 31, the S phase winding 32, and the T phase winding 33 are wound in the same phase. There is. At this time, since the generated magnetic fluxes in the normal mode cancel each other out and the generated magnetic fluxes in the common mode strengthen each other, the detection coil has a high inductance value only in the common mode and acts as a common mode choke coil. Further, the common mode noise 4 passing through the detection transformer generates a noise detection signal 35 at both ends of the auxiliary winding 34. Both ends of the output of the auxiliary winding are connected to the waveform signal forming circuit 40.

FIG. 6 is an example of the waveform signal forming circuit according to the first, second, third, fourth, and fifth embodiments, and shows a case where the band limiting circuit 41 and the high frequency amplifier circuit 42 are configured. The band limiting circuit 41 attenuates low frequency components that are unnecessary for noise compensation by, for example, a passive filter composed of a resistor and a capacitor. The high-frequency amplifier circuit 42 forms an inverting or non-inverting amplifier circuit using, for example, an operational amplifier 45, and amplifies a signal whose unnecessary components are cut by the band limiting circuit 41 according to the ratio of the input resistor 43 and the feedback resistor 44. ..

FIG. 7 is a configuration example of the signal transmitter according to the first, second, third, fourth, and fifth embodiments, and shows a case where the signal transmitter is configured by a common mode transformer. The injection transformer 50 is inserted into the RST phase power line between the detection circuit 30 and the power conversion device 80, and the R phase winding 51, the S phase winding 52, and the T phase winding 53 are wound in the same phase. Here, a noise injection signal 55 is input to the auxiliary winding 54 so as to cancel the common mode noise (not shown) with respect to the common modes of the R-phase winding 51, the S-phase winding 52, and the T-phase winding 53. Common mode injection voltage 56 is input.

Here, when the power converter 80 is temporarily overloaded or unbalanced due to a sudden load change or the like, the load current value temporarily rises, so that the magnetic flux of the normal component generated in the signal transmitter temporarily rises. do. The magnetic flux generated in the injection transformer 50, which is one of the signal transmitters, is the sum of the magnetic flux of the normal component generated by the product of the leakage inductance and the normal current and the magnetic flux of the common mode component generated by the active operation of the noise suppression device. be. Of these, the magnetic flux of the normal component rises, and the magnetic flux density in the core rises.

In other words, in order not to cause magnetic saturation of the core, the core magnetic design of the common mode transformer must be performed in consideration of the temporary overload or the rise of the normal component magnetic flux in the unbalanced state, and the core size is large. There was a problem that it became large and hindered miniaturization or cost reduction.

In the present embodiment, when the current state signal 68a of the injection current output from the injection current sensor (not shown) provided in the noise suppression device is input to the state detector 60 and the input value exceeds a predetermined threshold value. (For example, in the case of overcurrent), the gain adjuster 70 can be used to reduce the gain by a predetermined time. As a result, among the magnetic flux generated in the core, the magnetic flux of the common mode component generated by the active operation of the noise suppression device is temporarily reduced, and the magnetic saturation of the core can be avoided. The current state signal, the protection state signal, the specific state signal, and the operation state signal, which will be described later, are collectively referred to as a state signal.

The operation of the first embodiment will be described with reference to FIGS. 8 and 9 showing the components of the present application.
FIG. 8 shows a configuration example of the gain adjuster 70 according to the first, second, third, fourth, and fifth embodiments, and shows a case where the gain adjuster 70 is configured by an up-down type digital potentiometer. Here, the gain adjuster 70 is composed of a control IC 71 and a digital potentiometer 72.

FIG. 9 shows an example of the operation of the configuration example of the gain adjuster 70 of FIG. 8 according to the first, second, third, fourth, and fifth embodiments. In FIGS. 8 and 9, the state detection signal 60a, which is one of the signals detected by the state detector 60, is represented by the low active signal DETECT (which is valid at the low level). The low active signal DETECT changes from high to low at timing t1 to detect an arbitrary state, and changes from low to high at timing t2 to end the detection of the arbitrary state.

Here, the control IC 71 switches the chip select signal 73 of the digital potentiometer 72 from high (a state in which the resistance value cannot be switched) to low (a state in which the resistance value can be switched) at timing t1, and sets the up / down control input 74 to high (a state in which the resistance value can be switched). Switch from (up count) to low (down count). Here, the logic of the three signals of the control IC 71 is all negative logic and is valid at a low level.

At this time, the digital potentiometer 72 synchronizes with the falling edge of the increment control input 75 from high to low, and the resistance value 76 rises or falls with a predetermined resolution width according to the high state or low state of the up / down control input 74.
Here, since the up / down control input 74 is low (down count), the resistance value 76 decreases, and the amplification gain of the high frequency amplifier circuit 42 decreases. After that, at the timing t2, after the increment control input 75 stops counting and becomes high, the chip selector signal is delayed by a predetermined return time 77 to switch from low to high, and the lowered resistance value 76 is converted to the non-volatile value of the digital potentiometer. The operation of returning the resistance value 76 to the initial value is performed without recording in the memory. By this recovery operation, the temporarily increased amplification gain returns to the original value again after a predetermined recovery time as the overcurrent state is released.

Here, when a temporary overload state occurs in the power converter 80 due to factors such as load fluctuations, the magnetic flux of the normal mode component is temporarily generated with respect to the core magnetic flux in the injection transformer 50, which is one of the signal transmitters. Therefore, in order to avoid the magnetic flux saturation of the core, it was necessary to design the magnetic flux of the core in consideration of the temporary overload state.

In the present application, the current state signal 68b obtained from the power conversion device 80, which is a controlled device, is input to the state detector 60, and when the input value exceeds a predetermined threshold value, the gain is determined by using the gain adjuster 70. After the protection state is released, the amplification gain can be returned to the original value again with a predetermined recovery time. As a result, in the magnetic flux design of the core of the injection transformer 50, which is one of the signal transmitters, the noise compensation operation can be realized without causing design restrictions due to a temporary overload state.

From the above, when the power converter 80 becomes a temporary overcurrent and the magnetic flux of the normal mode component among the core magnetic fluxes represented by the sum of the common mode and the normal mode temporarily increases, the injection transformer is provided by the waveform signal forming circuit. By temporarily reducing the magnetic flux of the common mode component transmitted to the core to reduce the maximum magnetic flux density of the core, the core size can be reduced, and the noise suppression device can be made smaller and the cost can be reduced. can do.

The current sensor output may be provided in the noise suppression device, and is not a direct current detection amount but an I / O signal (for example, an overcurrent state notification signal, a load sudden change notification signal, etc.) from the device. May be good.

The band limiting circuit includes not only a high-pass filter that suppresses low frequencies, but also a low-pass filter that suppresses high frequencies, a notch filter that suppresses a specific band, a band-pass filter that passes a specific band, and the like within a range that does not deviate from the purpose of the present application. It can be configured freely. Further, the high-frequency amplifier circuit can be freely configured within a range that does not deviate from the gist of the present application, such as an inverting amplifier circuit using an operational amplifier and a non-inverting amplifier circuit.

Further, the configuration of the present embodiment may be not only a three-phase three-wire power conversion system but also a three-phase four-wire power conversion system. Further, the gain adjuster is a combination of a control IC and a digital potentiometer having a communication interface, a combination of an analog network and an up-down digital potentiometer, a resistance short circuit using a semiconductor switch, or a load switch between different analog control networks. It can be freely configured within a range that does not deviate from the gist of the present application, such as switching the resistance and capacitor capacitance value by switching between the two, and switching the resistance value by an electronic resistance whose resistance value can be changed.

Embodiment 2.
FIG. 10 is a circuit of the noise suppression device 20 according to the second embodiment.
The difference between the noise suppression device 20 according to the second embodiment and the noise suppression device 20 according to the first embodiment is that the signal input to the state detector 60 is a protection state signal 65 instead of the current state signal 68a. It is a point.

Here, when the injection current becomes an overcurrent in the waveform signal forming circuit 40 for some reason (for example, when the common mode transformer of the signal transmitter which is a noise injection means causes instantaneous magnetic saturation due to the intrusion of external noise such as a lightning surge). ), It is necessary to stop the operation of the device in order to protect the circuit components of the waveform signal forming circuit 40. However, when this operation is realized by selecting a component with a built-in protection circuit as the circuit component of the waveform signal forming circuit 40, the component with a built-in protection circuit is generally expensive and there are restrictions on the lineup, so there are design restrictions. There was a problem that caused.

FIG. 11 is a configuration example of the state detector 60 according to the first, second, third, fourth, and fifth embodiments, and shows a case where the state detector 60 is configured by a single injection current overcurrent detection circuit. Here, the shunt resistance 61 inserted in series with respect to the output of the waveform signal forming circuit 40 and the input of the injection transformer 50, which is one of the signal transmitters, and both ends of the shunt resistance in proportion to the injection current value. It is composed of a comparator 62 that compares the generated injection current detection voltage with a predetermined threshold, and a threshold creation circuit 63 that supplies a predetermined threshold to the comparator 62, and the output of the comparator 62 becomes an overcurrent detection signal of the injection current.

In addition, the state detector 60 receives a specific state signal 66 (for example, an overload state detection signal indicating that the device is in an overload state) indicating a specific state from the power conversion device 80 which is a controlled device. An interface circuit that receives from the O port may be added. Further, an interface circuit for receiving an overheat state detection signal from the thermistor provided in the cooling fin for cooling the heat generating component of the injection circuit may be added.

In the noise suppression device of the present embodiment, the protection state signal 65 obtained by an appropriate means such as an inexpensive shunt resistor 61 provided in the waveform signal forming circuit 40 is input to the state detector 60, and the input value is a predetermined threshold value. When the value exceeds, the gain adjuster 70 can be used to reduce the gain for a predetermined time, and after the protection state is released, the amplification gain can be returned to the original value again with a predetermined recovery time.

This makes it possible to realize a protective operation without causing design restrictions in the selection of circuit components of the waveform signal forming circuit 40.

From the above, when the magnetic saturation of the core occurs and the injection current for noise compensation becomes an overcurrent, the magnetic flux of the common mode component among the core magnetic fluxes indicated by the sum of the common mode component and the normal mode component is temporarily used. By reducing the maximum magnetic flux density of the core, the core size can be reduced, and the noise suppression device can be reduced in size and cost.

Embodiment 3.
The third embodiment is a modification of the second embodiment shown in FIG.
The difference between the noise suppression device 20 according to the third embodiment and the noise suppression device 20 according to the second embodiment is that the operation of the gain adjuster 70 after the detection of the protection state signal is performed after a predetermined recovery time has elapsed. The point is that the amplification gain is gradually lowered to a minute value without immediately returning to the original amplification gain, and then raised again to reach the recovery.

Here, consider a case where the output of the noise suppression device 20 is cut off by some kind of protection operation of the waveform signal forming circuit 40. At this time, a residual magnetic flux is generated inside the core according to the hysteresis characteristic of the core magnetic material immediately before the output is cut off. Assuming that the cause of the protective operation is removed and the noise suppression device 20 starts outputting again, when the noise suppression device operates at a normal gain, the residual magnetic flux is added to the normally generated magnetic flux, so that the magnetism of the common mode transformer core There is a risk of saturation. Among the core magnetic materials, a core having a high magnetic permeability, for example, a nanocrystalline magnetic material having a high magnetic permeability such as Finemet, has a problem because the residual magnetic flux is larger than that of a general ferrite material.

In the present application, when the noise suppression device 20 is restarted, the compensation gain of the waveform signal forming circuit 40 is returned to the value before the protection operation is activated, and the amplification gain is gradually reduced to a minute value. As a result, the residual magnetic flux can be demagnetized.

This makes it possible to apply a core magnetic material having a large residual magnetic flux by avoiding the generation of a rush current due to magnetic saturation. Further, when the noise suppression device 20 starts output again after being cut off by the protection operation, the compensation gain is gradually increased over a predetermined time to soft-start the waveform signal forming circuit 40 and consume the circuit. It is possible to suppress current overshoot and reduce the circuit power supply capacity.

Embodiment 4.
FIG. 12 is a circuit of the noise suppression device according to the fourth embodiment.
The difference between the noise suppression device 20 according to the fourth embodiment and the noise suppression device 20 according to the second embodiment is that the signal input to the state detector 60 is an operating state signal 69a instead of the protection state signal 65. It is a point.

Here, when the power conversion device 80 has a plurality of operation modes, when the operation modes of the devices are switched, the switching pattern of the semiconductor switch changes, so that the amplitude of noise and the generated frequency generally change, and the noise standard. The amount of attenuation required for the noise suppression device 20 or the frequency characteristic changes in order to satisfy the above conditions.

Therefore, it is difficult to design the noise suppression device 20 corresponding to all operation modes, which hinders the reduction of the circuit component rating and the circuit power supply capacity of the noise suppression device 20 or the maximization of the noise suppression effect. ..

In the present embodiment, the operating state signal 69b obtained from the power converter 80 is input to the state detector 60, and the gain adjuster 70 is used to set the amplification gain of the waveform signal forming circuit 40 to the value of the operating state signal 69b. It can be changed to a predetermined amplification gain according to the situation.

As a result, in the magnetic flux design of the core of the waveform signal forming circuit 40 and the injection transformer 50 which is one of the signal transmitters, the noise compensation operation can be realized without causing the design constraint of the noise suppression device 20 depending on the operation mode. can.

From the above, when the power converter 80 has a plurality of operation modes having different noise amplitudes and generation frequencies, the amplification gain of the waveform signal forming circuit 40 is operated according to each noise amplitude and generation frequency pattern. By changing the amplification gain to a predetermined value according to the value of the state signal 69a, the core size of the waveform signal forming circuit 40 and the injection transformer 50, which is one of the signal transmitters, can be reduced, and the noise suppression device 20 can be reduced in size. The noise suppression effect can be maximized while reducing the circuit component rating and circuit power supply capacity.

Embodiment 5.
The fifth embodiment is a modification of the first, second, third, and fourth embodiments.
Here, regarding the protection operation of the waveform signal forming circuit 40 according to the first embodiment, typically, when the amount of noise or the frequency band of noise changes due to heat generation of the device or a transformer, it is optimal. As the compensation gain changes, the protection operation may continue to work.

In order to avoid this, it is typically necessary to design the noise attenuation amount or circuit power supply capacity in consideration of robustness under thermal or electrical conditions, resulting in miniaturization or cost reduction. It was a hindrance.

In the present embodiment, when the protection operation is continuously performed a predetermined number of times or more within a predetermined time width, it is considered that the optimum amplification gain has changed to a low value, and the gain adjuster 70 determines only the predetermined width. Permanently reduce the amplification gain.

As a means for realizing this, unlike the operation example of the first embodiment shown in FIG. 10, after the lapse of a predetermined recovery time, the chip select signal 73 is started up while the increment control input 75 is not in the low state but in the high state. By writing the set resistance value setting of the digital potentiometer 72 (see FIG. 8) of the gain adjuster 70 to the non-volatile memory, the amplification gain is permanently reduced by a predetermined width.

Furthermore, if the protection operation does not work at all within a predetermined time width, the optimum amplification gain is considered to be at a higher value, and the gain adjuster can permanently increase the amplification gain by a predetermined width. can. As a result, a compact, low-cost, and robust noise suppression device can be realized.

FIG. 13 shows an example of the hardware 92 related to the signal processing of the noise suppression device of the present application. As shown in this figure, at least a part of the hardware 92 related to the signal processing of the present apparatus (specifically, the waveform signal forming circuit 40 shown in FIGS. 4, 10 and 12 or the state detector 60 is applicable. Includes a processor 93 and a storage device 94. Although the storage device is not shown, it includes a volatile storage device such as a random access memory and a non-volatile auxiliary storage device such as a flash memory. Further, an auxiliary storage device of a hard disk may be provided instead of the flash memory. The processor 93 executes the program input from the storage device 94. In this case, the program is input from the auxiliary storage device to the processor 93 via the volatile storage device. Further, the processor 93 may output data such as a calculation result to the volatile storage device of the storage device 94, or may store the data in the auxiliary storage device via the volatile storage device.

1 AC power supply, 2 Power supply line between AC power supply and power converter, 3 Ground line, 4 Common mode noise, 10 Noise filter, 11 Ground capacitor, 20 Noise suppression device, 30 Detection circuit, 31, 51 R-phase winding, 32, 52 S-phase winding, 33, 53 T-phase winding, 34, 54 auxiliary winding, 35 noise detection signal, 40 waveform signal formation circuit, 41 band limiting circuit, 42 high-voltage amplification circuit, 43 input resistance, 44 feedback Resistance, 45 optotype, 50 injection transformer, 55 noise injection signal, 56 common mode injection voltage, 60 state detector, 60a state detection signal, 61 shunt resistance (current detection resistance), 62 comparator, 63 threshold creation circuit, 65 protection state Signal, 66 specific state signal, 68a, 68b current state signal, 69a, 69b operation state signal, 70 gain adjuster, 71 control IC, 72 digital potential meter, 73 chip select signal, 74 up / down control input, 75 increment control input, 76 resistance value, 77 return time, 80 power converter, 81, 91 ground parasitic capacitance, 82a, 82b, 84a, 84b, 86a, 86b semiconductor switch, 83 U-phase up / down arm, 85 V-phase up / down arm, 87 W-phase up / down Arm, 88 inverter output end, 89 inverter DC power supply, 90 load, 92 hardware, 93 processor, 94 storage device, 100 power conversion system, Vcm common mode voltage

Claims

A noise suppression device that is arranged between an AC power supply and a controlled device and transmits a signal to the controlled device.
A detection circuit that detects a specific signal and
A waveform signal forming circuit that forms a predetermined waveform signal from a specific signal detected by this detection circuit, and
A signal transmitter that transmits the waveform signal formed by the waveform signal forming circuit to the controlled device, and
A state detector that detects a state signal representing the state of the controlled device or the waveform signal forming circuit, and
A gain adjuster built in the waveform signal forming circuit and adjusting the gain of the waveform signal according to any one of the state signals detected by the state detector.
With
A noise suppression device characterized in that a waveform signal adjusted by the gain adjuster is transmitted to the controlled device.
When the state detector detects that an overcurrent has occurred in the waveform signal forming circuit, the gain of the waveform signal is temporarily lowered at the time of detecting the overcurrent, and after the overcurrent state is resolved, the above-mentioned The noise suppression device according to claim 1, wherein the gain of the waveform signal is returned to the magnitude at the time of detecting the overcurrent.
When the state detector detects that the load connected to the controlled device is in an overloaded state, the state detector temporarily reduces the gain of the waveform signal at the time of detecting the overloaded state, and at the same time, the overloaded state is detected. The noise suppression device according to claim 1, wherein the gain of the waveform signal at the time of detecting the overload state is returned after the load state is released.
The controlled device is temporarily stopped, or the waveform signal forming circuit is temporarily stopped by a protection signal of the waveform signal forming circuit input from the state detector, and then stopped. When restarting the control device or the stopped waveform signal forming circuit, the gain adjuster is made to perform an operation of gradually lowering the gain and then gradually increasing the gain. The noise suppression device according to claim 1.
When the controlled device has a plurality of operation modes and the state detector detects that the operation mode of the controlled device has been switched, the gain adjuster adjusts the gain of the waveform signal to each operation mode. The noise suppression device according to claim 1, wherein the gain is changed according to the above.
When the waveform signal forming circuit detects a protection signal more than a predetermined number of times within a set time, the gain adjuster switches the gain of the waveform signal to a value reduced by a predetermined value range, and sets the predetermined time. The noise suppression device according to claim 1, wherein the gain adjuster switches the gain of the waveform signal to a value increased by a predetermined value range when the protection operation does not occur beyond the limit.
The noise suppression device according to claim 1, wherein the detection circuit and the signal transmitter are composed of a common mode transformer.
The noise suppression device according to claim 1, wherein the waveform signal forming circuit is composed of a band limiting circuit and a high frequency amplifier circuit.
The state detector includes a shunt resistor connected in series with the signal transmitter, a comparator that compares the voltage generated across the shunt resistor with a predetermined threshold value, and a threshold value that gives the comparator the predetermined threshold value. The noise suppression device according to claim 1, further comprising a creation circuit.
The claim is characterized in that the gain adjuster is composed of any of a load switch for switching between different control networks, a semiconductor switch for short-circuiting circuit components to change a constant, and an electronic resistance whose resistance value can be changed. The noise suppression device according to 1.