JP2002272132A - Leakage-preventing equipment and leakage-preventing method for inverter drive load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain small-sized leakage-preventing equipment of high reliability. SOLUTION: In figure, the reference numeral 1 is constituted of the leakage- preventing equipment, the numeral 2 constituted of a main body, and the numeral 3 shown a commercial power source. The equipment 1 consists of an impedance 4, equivalent to a leakage impedance 8 of a load of the body 2, a switching part 5 for applying voltage to the impedance equivalent to the leakage impedance of the load, a drive part 6 for driving the switching part 5, and a control unit 7 for producing a switching pattern. The switching part 5 of the equipment 1 uses the output of a body converter 12 as a power source. A control unit 9 of the body 2 and the control unit 7 of the equipment 1 are realized on the same microprocessor, and its control is performed on a program assembled in the microprocessor. The drive part 6 and the switching part 5 are constituted of electronic components of low-current capacity (about at most 500 mA).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the prevention of earth leakage used in a system using a load driven by an inverter.

[0002]

2. Description of the Related Art FIG.
FIG. 4 is a circuit configuration diagram showing a conventional earth leakage prevention device disclosed in Japanese Unexamined Patent Application Publication No. 4 (Kokai) No. 4-No. This concerns the AC servo. Ideally, the primary winding groups U, V, and W of the leakage prevention transformer are the drive lines of the three-phase AC motor 115, and the sum of the currents flowing through them is always zero. But transistor switch 1
Since the pulse width modulation is performed by the pulse width modulation circuit 03, the voltage is always switched between the positive voltage and the negative voltage, and the charging and discharging of the floating capacitance 106 is repeated. This charging / discharging current becomes the total input of the leakage prevention transformer primary winding group. Then, the secondary winding of the leakage prevention transformer is connected to the outside (the ground E) of the motor 115 and the power supply unit through the DC insulated return capacitor 108.
Marks attached to the primary and secondary windings of the earth leakage prevention transformer indicate the beginning of the winding. Thereby, the motor 115
The charge / discharge current of the stray capacitance is forcibly returned from the secondary side of the leakage prevention transformer 107 to the power supply unit, and the current returning to the power supply 100 through the ground E is reduced.

[0003]

The above-mentioned conventional earth leakage prevention device requires an earth leakage prevention transformer. Since this leakage prevention transformer is inserted into the current line of the load, it requires the same current capacity as the load. Furthermore, the current flowing through the stray capacitance has a high frequency, and a leakage prevention transformer having good high-frequency characteristics must be used. For this reason, the countermeasure device becomes expensive. In addition, there is a disadvantage that the earth leakage prevention transformer is large and the installation place is restricted.

[0004] In particular, in an inverter-driven compressor, a motor is built in a container of the compressor, and a refrigerant circulating in a refrigeration cycle and a refrigerating machine oil of the compressor are constantly applied to the motor in a gaseous or liquid state and immersed therein. Electric leakage is likely to increase. In addition, in the case of the alternative CFC refrigerant, the characteristics of the refrigerant deteriorate and the generation of moisture further increases. Therefore, the introduction of a CFC alternative refrigerant containing hydrofluorocarbon as a main component is expected to increase the amount of leakage, thereby saving cost. Countermeasures in space are desired. This is the dielectric constant of CFC alternative,
Due to the higher conductivity than the current one and the compatibility of the new refrigerant and the refrigerating machine oil, the compressor with the same insulation design is expected to increase the amount of leakage. In addition, if the insulation design is changed due to this, the cost and the long development period due to the design change are required. Further, even if a highly reliable insulation design is obtained, quality measures such as measures for moisture in a product manufacturing process become complicated.

The present invention has been made to solve such a problem, and has as its object to provide an inexpensive, compact, and highly versatile earth leakage prevention device. Another object of the present invention is to provide an inverter device for driving loads such as compression which are highly reliable and easy to handle.

[0006]

According to a first aspect of the present invention, there is provided a DC power supply for an inverter or a separately provided DC power supply, switching means for switching DC from the DC power supply and converting the DC to AC, An impedance generated by the means is applied to one end and the other end is grounded, and an inverter is connected to a control device for generating an AC voltage signal to be applied to the drive load. And a control unit for generating a signal to drive the switching unit, wherein the impedance unit has an impedance amount for generating a current having a phase opposite to that of the ground leakage current of the load driven by the inverter.

According to a second aspect of the present invention, there is provided an impedance section having an impedance corresponding to an impedance against earth leakage of a load driven by an inverter which switches a direct current to generate an alternating current, a direct current power supply of the inverter or another direct current. A switching unit that switches a direct current from a power supply and energizes the impedance, a driving unit that drives the switching unit, generates a switching pattern of the switching unit based on control information of a control unit of the inverter, and supplies the switching pattern to the driving unit. It has a control unit that performs

According to a third aspect of the present invention, the switching pattern of the switching section generates a current having a phase opposite to that of the ground leakage current of the load.

According to a fourth aspect of the present invention, there is provided an electric leakage prevention device having a leakage current detecting section for detecting information on ground leakage of an inverter driving load, and controlling or controlling an AC voltage generation based on the information of the leakage current detecting section. This is to change the impedance amount of the impedance section.

According to a fifth aspect of the present invention, there is provided an earth leakage preventing device having a leakage current detecting unit for detecting earth leakage information of an inverter drive load, providing the earth leakage information to a control unit, and changing the operation of the switching unit. .

According to a sixth aspect of the present invention, there is provided an electric leakage prevention device having a leakage current detecting unit for detecting information on ground leakage of an inverter driving load, providing the electric leakage information to the driving unit, and changing the operation of the switching unit. .

According to a seventh aspect of the present invention, there is provided an earth leakage preventing apparatus having a leakage current detecting section for detecting information on ground leakage of an inverter driving load, providing the earth leakage information to the impedance section, and changing the amount of the impedance. Is what you do.

According to an eighth aspect of the present invention, there is provided an electric leakage prevention device according to the present invention, wherein a power supply of a switching unit is a variable power supply, and a leakage current detecting unit for detecting ground leakage information is provided. Change the bus voltage of

According to a ninth aspect of the present invention, there is provided an earth leakage preventing device having an impedance portion having an impedance corresponding to an impedance of a load driven by an inverter against earth leakage, a switching portion for switching a DC power supply and supplying current to the impedance, A driving unit for driving the switching unit; and a control unit for generating a switching pattern of the switching unit based on driving information of the driving unit of the inverter and supplying the switching pattern to the driving unit.

According to a tenth aspect of the present invention, there is provided an earth leakage preventing device having an impedance portion having an impedance corresponding to the impedance of a load driven by an inverter against earth leakage, a switching portion for switching a DC power supply and supplying current to the impedance, A driving unit for driving the switching unit; and a control unit for generating a switching pattern of the switching unit based on switching information of the switching unit of the inverter and supplying the switching pattern to the driving unit.

According to an eleventh aspect of the present invention, the control unit has a delay unit.

According to a twelfth aspect of the present invention, the drive unit has a delay unit.

According to a thirteenth aspect of the present invention, there is provided an earth leakage preventing device, wherein at least a capacitor is connected in series between each phase of the impedance section and the ground, and a resistor and a coil are connected in series between each phase and a place where each phase is put together. It has.

According to a fourteenth aspect of the present invention, a first leakage impedance circuit is provided from a DC power supply via switching means, and a second leakage impedance circuit is provided from a DC power supply. Some of the elements of the circuit are common.

According to a fifteenth aspect of the present invention, there is provided an earth leakage prevention device comprising: a transistor connected to each phase of the switching unit; a diode connected in parallel with a resistor between each phase of the impedance unit and the ground; Further, there is a resistance between each phase and the bus of the switching section.

According to a sixteenth aspect of the present invention, a resistor, a capacitor, and a coil are connected in series between each phase of the impedance part and the ground.

According to a seventeenth aspect of the present invention, a resistor, a coil, or a diode connected in series between each phase of the impedance part, the ground, and the bus is shared.

According to an eighteenth aspect of the present invention, there is provided an earth leakage prevention device using an integration circuit in a drive unit.

According to a nineteenth aspect of the present invention, the value of each element of the impedance section is variable.

According to a twentieth aspect of the present invention, the total switching number of the switching unit is N or less for an N-phase load.

According to a twenty-first aspect of the present invention, there is provided an earth leakage preventing apparatus in which an impedance section and a control device for controlling the driving of a switching section for applying a voltage to the impedance section are integrated in the same IC.

According to a twenty-second aspect of the present invention, a leakage impedance circuit is provided between one end and the other end of a DC power supply and the ground via switching means, and at least a part of each impedance circuit is common. .

According to a twenty-third aspect of the present invention, there is provided an earth leakage prevention device, comprising: a PNP-type switching element connected to one end of a DC power supply; an NPN-type switching element connected to the other end of the DC power supply; And a ground leakage impedance circuit equivalent to an inverter driving load connected between the two switching elements to the ground.

According to a twenty-fourth aspect of the present invention, there is provided a method for preventing a leakage to an inverter driving load, wherein an AC voltage generated by the inverter is applied to the driving load, and a voltage whose phase is inverted in synchronization with the AC voltage is generated. Setting a current equivalent to a ground leakage current flowing when the AC voltage is applied to the driving load, and setting an impedance flowing when the inversion voltage is applied; and canceling the ground leakage current and the equivalent current. Grounding the driving load and the impedance as possible.

According to a twenty-fifth aspect of the present invention, there is provided a method for preventing electric leakage from an inverter driving load, comprising the steps of changing a voltage applied to an impedance to follow a change in leakage current leaking from the inverter driving load to the ground.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram showing a configuration of an earth leakage prevention device according to an embodiment of the present invention, wherein 1 is a configuration of an earth leakage prevention device, 2 is a configuration of a main body including a converter / inverter device and a motor, and 3 is a commercial power supply. It is. 1 is a leakage prevention device, 4 is an impedance equivalent to the leakage impedance 8 of the main body load, 5 is a switching unit for applying a voltage to the load leakage impedance equivalent impedance of 4, 6 is a driving unit for driving the 5 switching unit, and 7 is a driving unit. The control unit generates a switching pattern. The power supply of the switching unit 5 of the earth leakage prevention device uses the output of the main converter 12. In the present embodiment, the control unit 9 of the main unit and the control unit 7 of the leakage prevention device are realized on the same microprocessor, and the control is performed on a program incorporated in the microprocessor. The drive unit 6 and the switching unit 5 are composed of electronic components having a low current capacity (about 500 mA or less). This is an example in which the present invention is applied to a three-phase compressor motor. Reference numeral 11 denotes a switching unit of an inverter device which is driven by a driving unit 10 and repeats ON / OFF, 12 denotes a converter for converting AC from a power source 3 to DC, and 13 denotes a motor. Make up.

In the example shown in FIG. 1, a control device and a motor are integrated into the main body 2 and a casing (not shown) of the main body.
And the ground terminal is connected to the ground. The leakage current from the motor 13 is transmitted from the coil energizing portion of the motor 13 to the outer enclosure of the motor through a core and an insulating surface. When the ground terminal is taken directly from the outer enclosure of the motor or as in a compressor,
Leakage current may flow through the sealed container to which the motor is fixed, and flow from the frame ground, that is, the sealed container to the ground. In particular, when a hydrofluorocarbon or a hydrocarbon is used as a main component and another type of refrigerant is mixed, the leakage current is likely to increase, so that the cancel current in FIG. 1 also increases.

The leakage impedance 8 of the motor shown in FIG.
FIG. 1 is an equivalent circuit for explanation showing that each of the three-phase windings exists, and does not mean neutral point grounding. Actually, it changes depending on the insulating material of each winding, the manufacturing condition, dirt and water adhesion during use of the motor, and leakage is likely to occur in a portion where winding insulation is weak. In addition, the cancel current shown in FIG. 1 is preferably connected to the same position as the earth line and canceled each other. However, it goes without saying that any cancel current may be used as long as it is ground (earth).

FIGS. 2A and 2B show the voltage and current waveforms of various parts of the present embodiment. FIG. 2A shows the output voltage of the U-phase of the main body, the voltage U between the U-phase terminal of the switching unit and the DC ground, and FIG. (C) is a voltage Uanti applied to the U-phase portion of the impedance 4 of the leakage prevention device,
(D) is a cancel current caused by voltage fluctuation of Uanti. The horizontal axis is the time axis.

The operation of the leakage prevention device of the present embodiment will be described with reference to FIGS. The explanation will focus on the U phase.
As shown in (a) and (b), the leakage current from the compressor motor leaks the electric charge charged to the capacitance component of the load leakage impedance 8 due to the switching of the phase voltage. On the other hand, in the earth leakage prevention device shown in the present embodiment, the switching circuit is driven from control information of the main body to generate a voltage as shown in (c) by generating a voltage as shown in FIG. Leakage is prevented by applying a current reverse to the leakage current of the main body as shown in FIG.

The equivalent impedance 4 can be obtained by applying a voltage to the motor windings U, V, and W to cause a current to flow, and measuring the leakage current at this time to determine the load leakage impedance. The same equivalent impedance as the obtained load leakage impedance may be set in advance by using a resistor, a coil, and a capacitor.
The U voltage of the main body is controlled by the control unit 9 and is switched by the switching unit 10 by generating a switching signal. On the other hand, a signal having an opposite phase to this signal is controlled by the controller 7 and generated by the driver 6, and the switching section 5 generates an anti-phase voltage. Since the output from the converter 12 is supplied to the switching unit 5 as it is, a voltage Uanti completely opposite to the U-phase voltage can be generated.

In FIG. 2A, when the U voltage and the Vanti voltage are respectively applied to equivalent leakage impedances, a U leakage current is generated from the motor 13 and tends to flow to the ground as shown by the arrow. On the other hand, from the equivalent impedance 4 of the leakage prevention device 1, a Vanti cancellation current having a phase completely opposite to that of the U leakage current flows so as to cancel each other out as a negative current as shown by an arrow in FIG.

The control units 9 and 7 and the drive units 10 and 6
About O of the transistor in the impedance section 11
It is only necessary to generate the same inversion voltage as the phase voltage for N and OFF, and it is natural that a simple circuit that generates an inversion signal in the driving unit 6 based on a signal from one control unit may be used. . In addition, the switching unit 5 and the equivalent impedance 4 only flow a leakage current, and a small-capacity switching element and components of R, L, and C can be used to form an IC circuit.

By adding the inversion voltage to the impedance equivalent to the leakage impedance as described above, it is possible to construct the system with simple electronic components and software in the microcomputer.
Since the configuration can be realized without using an expensive and large product such as an earth leakage prevention transformer, an inexpensive and small earth leakage prevention device can be obtained. In addition, since it is composed of small-capacity components, it is possible to implement an IC that was not possible with the conventional configuration, and if the IC is employed, it is possible to further reduce the size and cost.

Embodiment 2 FIG. 3 shows another configuration diagram of the earth leakage prevention device according to one embodiment of the present invention. Reference numeral 15 denotes a constant voltage source that supplies a DC voltage to the switching unit 5. In the first embodiment, the output of the main body converter 12 is used as the power supply of the switching unit 5 of the earth leakage prevention device. However, the same operation can be performed even when a configuration using a DC power supply different from the main body is used. Further, when the output voltage of the converter is high, if the power supply of the switching unit 5 of the leakage prevention device is constituted by another low-voltage DC power supply, a voltage much lower than the converter output voltage can be used.
, And the withstand voltage of the equivalent circuit components can be reduced.

As described above, since the configuration can be realized without using expensive and large components such as a leakage prevention transformer, an inexpensive and small leakage prevention device can be obtained. Furthermore, even if the setting of the equivalent impedance goes wrong or changes during long-term operation, it is possible to easily change the applied current voltage 15 to cope with the problem and to obtain a device which is easy to handle.

Embodiment 3 FIG. 4 shows another configuration diagram of the earth leakage prevention device according to one embodiment of the present invention. Reference numeral 16 denotes a leakage current detection unit that detects the leakage current of the main body and outputs the information, and notifies the control unit 7 of the state of the leakage current. In the first and second embodiments, the cancellation current is generated without considering the actual state of the leakage current. However, in the present embodiment, the leakage current and the cancellation current are detected in order to detect the information of the leakage current and reflect the information in the control. Can be corrected if there is a deviation, the deviation between the main body load leakage impedance 8 due to aging and the load leakage impedance equivalent impedance of the leakage prevention device, and U, V, W and Uan due to the time delay of each part.
It is possible to cope with a shift in ti, Vanti, and Wanti voltage fluctuation timings. FIG. 5 illustrates an example of the configuration of the leakage current detection unit. One end of the switching 11 is connected to the motor frame 80 of the motor 13 via the capacitor 81 and the resistor 82. The high-frequency leakage voltage is
Can be detected by the high resistance 82 in a state where almost no current flows. That is, regarding the method of detecting the leakage current, a resistor is inserted between the motor frame 80 and a bus, for example, the minus side of the switching unit 11, and the voltage across the resistor is detected. This voltage is correlated with the leakage current. If only the detection function is used, only a resistor is sufficient, but a capacitor is usually inserted in series to maintain DC insulation. It is considered that a resistance value of several kilo-ohms and a capacitor of several thousands to several hundred pF are appropriate. In this case, the timing becomes a problem rather than the magnitude of Uanti, and the switching voltage Uanti for obtaining a countermeasure current has the same voltage waveform in a short time span (relative to the switching time) defined by the passive element LCR. In the present embodiment, the size is desired to be variable, and the leakage current is reduced.

In an actual product, there is a delay between the switching timing generated by the control unit 9 and the timing of the voltage change at the output of the switching unit 11. In particular, the delay of the switching unit is affected by variations in elements and the amount of output current. In the present embodiment, the information on the timing delay of the main body is detected by the 16 leakage detection units, and the control unit 7 of the leakage prevention device corrects the time delay, so that the deviation can be dealt with. As a result, an electric leakage prevention device that responds to variations in switching elements and fluctuations in operating current can be obtained. Further, in this embodiment, since the correction is performed by the control unit, if the control unit is realized in the main body microprocessor, it can be coped with by software, so that the configuration can be made inexpensively.

FIG. 6 is a timing chart of the drive signal and the leakage current, and FIG. 7 is a flowchart for explaining this operation. In this example, the change in the time timing of the peak voltage of the voltage waveform correlated with the obtained leakage current (solid arrow in FIG. 6) is used as the correction value of the signal change timing of the drive signal of the leakage prevention device of the prevention device. However, it is necessary to momentarily cut the cancel current for timing measurement. The method of correction is to hold the peak delay time from the normal drive signal change in FIG. 6 as a hold value, calculate the difference from the actual delay time in FIG. 6, and change the drive signal of the prevention device by the difference time. Stagger the timing. FIG. 7 is a flowchart showing this operation. The processing in FIG. 7 is performed by periodic interrupt processing.

In FIG. 7, since the control unit 7 performs a correction operation,
When periodic interruption processing is performed in TO1, first, the voltage applied to the equivalent impedance is cut, and the generation of the cancel current is cut (STO2). Next, the voltage between both ends of the resistor 82 of the detection unit 16 is measured, and the ON and O of the switching unit 11 are turned on.
The delay time 1 between the time with the FF and the actual leakage current (that is, the measured voltage) is obtained (STO3). The delay time 1 is obtained as data in advance, and the stored time 1 'is subtracted (STO4) to correct the timing of the signal output from the drive unit 6 and apply a voltage to be applied to the equivalent impedance 4 (STO5). . This terminates the interrupt processing (STO6).

As described above, since the configuration is such that compensation during operation can be realized without using expensive and large parts such as an earth leakage prevention transformer, an inexpensive and small earth leakage prevention device can be obtained. A highly reliable earth leakage prevention device corresponding to the above variation can be obtained.

Embodiment 4 FIG. 8 shows a configuration diagram of an earth leakage prevention device according to an embodiment of the present invention. 1
Reference numeral 6 denotes a leakage current detection unit that detects the leakage current of the main body and outputs the information, and notifies the driving unit 6 of the state of the leakage current. In the first and second embodiments, the cancellation current is generated without considering the actual state of the leakage current. However, in the present embodiment, the leakage current and the cancellation current are detected in order to detect the information of the leakage current and reflect the information in the control. Can be corrected if a deviation occurs, the deviation between the main body load leakage impedance 8 due to aging and the load leakage impedance equivalent impedance of the leakage prevention device, and U, V, W and Uanti, V due to the time delay of each part.
It is possible to cope with a shift in anti and Wanti voltage fluctuation timings.

In an actual product, there is a delay between the switching timing generated by the control unit 9 and the timing of the voltage change at the output of the switching unit 11. In particular, the delay of the switching unit is affected by variations in elements and the amount of output current. In the present embodiment, the information of the timing delay of the main body is detected by the 16 leakage detection units, and the time delay is corrected by the drive unit 6 of the leakage prevention device. As a result, an electric leakage prevention device that responds to variations in switching elements and fluctuations in operating current can be obtained. Further, in this embodiment, since the correction is performed by the drive unit, it can be retrofitted in response to the existing load, and a highly versatile earth leakage prevention device can be obtained.

In FIGS. 6 and 7, the correction is performed by software, that is, a microcomputer program of the control unit 7. However, in the present embodiment, the correction is performed by a circuit configuration of the driving unit 6. FIG. 9 shows a circuit configuration for performing the correction. Control unit 7
, A switching signal is generated by the drive circuit 84, and the actual time from the leakage current detection unit and the time of the signal from the control unit 7 are measured by the time difference measurement circuit 85 on the way. (86), and the timing to the switching section 5 is changed to the variable signal delay circuit 83
And a drive signal is generated by the drive circuit 84.

If the processing capacity of the microcomputer of the main body has a margin, the cost can be minimized by realizing software on the microcomputer. However, if there is no margin in the microcomputer capacity, the circuit is more complicated than mounting another microcomputer. It is easier for the system to be realized by the configuration. As described above, the configuration that can realize correction during operation without using expensive and large parts such as an earth leakage prevention transformer can be obtained, so that an inexpensive and small earth leakage prevention device can be obtained. And a highly reliable earth leakage prevention device corresponding to the above.

Embodiment 5 FIG. FIG. 10 shows a configuration diagram of an earth leakage prevention device according to an embodiment of the present invention.
Reference numeral 16 denotes a leakage current detection unit that detects the leakage current of the main body and outputs the information, and transmits the state of the leakage current to the load leakage impedance equivalent impedance 4. In the first and second embodiments, the cancellation current is generated without considering the actual state of the leakage current. However, in the present embodiment, the information of the leakage current is detected, the impedance is adjusted, and the leakage current and the cancellation current are adjusted. Can be corrected when a deviation occurs, the deviation between the main body load leakage impedance 8 due to aging and the load leakage impedance equivalent impedance of the leakage prevention device, and U, V, W and Uanti, Vant due to the time delay of each part.
It is possible to cope with a shift in i, Wanti voltage fluctuation timing and the like. The fifth embodiment of the invention is a modification of the third and fourth embodiments. In the fifth embodiment of the invention, the correction is performed by using the equivalent impedance of the load leakage impedance. The feature is that correction is applied to the entire waveform. L in the equivalent impedance section
When a CR series circuit is used, the cancel current for each value is approximately expressed by FIG. 11 and the equation in FIG. FIG. 12 shows the relationship between the leakage impedance and the leakage current.

In FIG. 10, L of the equivalent impedance 4
Each value of CR can be made variable by providing a tap in each element and switching a circuit from each tap by a switching element. The algorithm for this correction will be described with reference to the flowchart of FIG. Interrupt processing (STO8)
Stops the output of the cancel current (STO9),
The voltage E and the currents i1 and i2 are measured, and the times ta and t
Measure d. Calculate the difference from the original value (ST11),
The LCR value of the equivalent impedance is corrected like the LCR value described in the equation of FIG. 11 (ST12).

In an actual product, the load leakage impedance changes depending on the state of the refrigerant in the compressor, and the amount of leakage from the compressor changes. Actually, the amount of electric leakage at the time of startup is high in air conditioners, etc. In contrast, the amount of electric leakage of the compressor is monitored and the impedance 4 is varied. Let it. In particular, a high-performance earth leakage prevention device corresponding to a change in the operation state of the load can be obtained.

As described above, since the configuration is such that the correction during operation can be realized without using expensive and large parts such as a leakage prevention transformer, an inexpensive and small leakage prevention device can be obtained. In addition, a highly reliable earth leakage prevention device that responds to aging, changes in operating conditions, and manufacturing variations can be obtained.

Embodiment 6 FIG. FIG. 14 is a diagram showing a configuration of a leakage prevention device according to an embodiment of the present invention.
A variable voltage source 17 supplies a DC voltage to the switching unit 5. Reference numeral 16 denotes a leakage current detection unit that detects the leakage current of the main body and outputs the information, and transmits the status of the leakage current to the variable voltage power supply. In the first and second embodiments, the cancellation current is generated without considering the actual state of the leakage current. However, the present embodiment detects the leakage current information and reflects the information on the power supply voltage. Since a correction can be made when a current deviation occurs, it is possible to cope with a deviation between the main body load leakage impedance 8 and the load leakage impedance equivalent impedance of the leakage prevention device due to aging. In contrast to the above-described example of FIG. 11 in which the LCR is made variable, the LCR is made constant and the applied voltage E is made variable.

In an actual product, the load leakage impedance changes depending on the state of the refrigerant in the compressor, and the amount of leakage from the compressor changes. In fact, in an air conditioner or the like, the amount of leakage at startup is high. On the other hand, the amount of leakage of the compressor is monitored and the voltage of the variable power supply 17 is varied. If the amount of leakage is large, the voltage is increased to increase the cancel current, and the amount of leakage is small. In some cases, the voltage is lowered to reduce the cancel current. In particular, a high-performance earth leakage prevention device corresponding to a change in the operation state of the load can be obtained.

FIG. 15 shows a flowchart of a correction algorithm for making the voltage variable. The difference from FIG. 13 is that the leakage current is measured to correct the cancellation current (ST16).
Just do it. Thus, since the resistance R is constant, the difference from the original value can be calculated (ST17), and the voltage value applied to the equivalent impedance 4 is corrected (ST1).
8) The interrupt process may be terminated and the leakage current cancellation current may be output.

As described above, since the correction of the cancel current can be realized without using expensive and large components such as a leakage prevention transformer, an inexpensive and small leakage prevention device can be obtained. In addition, a highly reliable earth leakage prevention device that responds to aging, changes in operating conditions, and manufacturing variations can be obtained.

Embodiment 7 FIG. FIG. 16 shows a configuration diagram of an earth leakage prevention device according to an embodiment of the present invention.
In the first to sixth embodiments, the drive information of the main body is provided to the earth leakage prevention device in the same microprocessor, but the drive information of the main body is taken into the control unit 7 constituted by a logic circuit from the drive unit 10 and the control of the earth leakage prevention device is performed. The same operation can be performed even if a switching pattern is generated. In this configuration, it can be retrofitted to an existing body.

As described above, since the configuration can be realized without using expensive and large components such as a leakage prevention transformer, an inexpensive and small leakage prevention device can be obtained. In addition, it is a highly versatile method that can be easily added later and a small device can be added later as a measure to reduce the leakage current of the existing machine, that is, as a measure for reducing the leakage current of the existing machine. That is, FIG. 17 shows an explanatory diagram in which this addition is performed only by the connection, and the signal O to the drive unit 6 of the earth leakage prevention device 1 is applied to the output wiring from the drive unit 10 of the main body 2.
It is only necessary to connect the crosses so that N and OFF are reversed. The seventh embodiment of the present invention is a modification of the embodiment, and the difference lies in where to obtain the switching information of the main body, that is, the information on the timing of the change of the phase voltage from the main body. Usually, the control unit is realized by software inside the microcomputer, the drive unit is configured by a low-voltage electronic circuit, and the switching unit is configured by a high-voltage electronic circuit. The minimum information required for the operation of the prevention device of the present invention is finally information on a change in the output phase voltage of the main body. In order to obtain this information, the order of the seventh embodiment is advantageous in terms of cost. However, since the delay time occurs in each part, the order is reversed in terms of the accuracy of the information.However, since the problem can be solved by adding it to any device later, the measures to cross only this connection are flexible. And a flexible leakage current prevention measure can be obtained.

Embodiment 8 FIG. FIG. 18 shows a configuration diagram of an earth leakage prevention device according to an embodiment of the present invention.
In the first to sixth embodiments, the drive information of the main body is provided to the earth leakage prevention device in the same microprocessor. However, the drive information is taken into the control unit 7 from the switching unit 11 of the main body to generate the switching pattern of the earth leakage prevention device. Can perform the same operation.

As described above, since the configuration can be realized without using expensive and large components such as a leakage prevention transformer, an inexpensive and small leakage prevention device can be obtained. It is highly versatile because it can be attached to an existing body. FIG. 19 shows a timing chart of information and output such as a drive signal, a phase voltage, and a leakage current in this embodiment. As shown in the figure, the rise and fall timings of the phase voltage are detected, and the controller is used as it is to set the timing of the earth leakage prevention device to generate the cancel voltage Uanti in which the phase voltage is inverted. In other words, although it is necessary for each part of the prevention device to perform processing without a delay time, it is possible to generate faithful timing without knowing the characteristics of the drive unit and the control unit of the main unit. It is possible to realize a general-purpose prevention device.

Embodiment 9 FIG. The embodiment of the present invention is obtained by adding delay means to the control unit 7 of the first embodiment.
FIG. 20 shows a control flowchart of the U-phase of the control unit 7 realized by the microprocessor of the present embodiment. In response to the detection of the U-phase voltage change by the control unit 9 of the main body (ST2)
0), a delay time variable by software (ST21), and a phase voltage change command of the earth leakage prevention device is output (S21).
By performing T22), it is possible to eliminate the timing shift due to the mismatch of the delay time between the main body and each part of the earth leakage prevention device.

As described above, since the configuration can be realized without using expensive and large components such as a leakage prevention transformer, an inexpensive and small leakage prevention device can be obtained. There is no output timing shift due to the difference in the delay time of each part, and a highly reliable earth leakage prevention device that responds to aging, changes in operating conditions, and manufacturing variations can be obtained. From the accuracy of the information, a better result than the first embodiment of the invention can be obtained.

Embodiment 10 FIG. In the embodiment of the present invention, a delay unit is added to the driving unit 6 of the first embodiment. FIG. 21 is a circuit diagram of the driving unit 6 and the switching unit 5 according to the present embodiment. Reference numeral 20 may be a variable resistor that electronically controls the resistance value. 21 is a capacitor, 22 is an inverting circuit, and 23 is a transistor for driving a power transistor of the switching unit. The driving unit can drive the switching unit with an arbitrary delay time by the value of the variable resistor 20. By providing the adjustable delay means, it is possible to eliminate a timing deviation due to an unmatched delay time between the main body and each part of the leakage prevention device. FIG. 22 shows an explanatory diagram of the delay time. The delay time is determined by a threshold level 22, which is a waveform of the intersection of 20, 21.

As described above, since the configuration can be realized with a simple circuit configuration without using expensive and large components such as a leakage prevention transformer, an inexpensive and small leakage prevention device can be obtained. There is no output timing shift due to the difference in delay time of each part, and a highly reliable and accurate earth leakage prevention device that responds to aging, changes in operating conditions, and manufacturing variations can be obtained.

Embodiment 11 FIG. FIG. 23A shows a circuit of a switching unit and a main body leakage impedance equivalent impedance unit of the earth leakage prevention device according to one embodiment of the present invention. 34 and 37 are resistors, 35 and 38 are coils, and 36 is a capacitor. In the present embodiment, Uanti, Vanti, and W are added by adding additional impedances 37 and 38 to the body leakage impedance equivalent impedance 4 of the first to tenth embodiments.
The voltage of anti is higher than the phase voltages U, V, W of the compressor.
Near the reverse phase voltage of

As a result, the effect of preventing electric leakage is higher than in the first to tenth embodiments. That is, the additional impedance 3
Reference numerals 7 and 38 denote impedances equivalent to the preset impedance of the load itself, not the leakage impedance between each phase and the neutral point, which is a place where each phase is put together. On the other hand, impedances 34, 35,
Since the capacitor 36 has the capacitor 36, the current flows to the main unit as a cancel current only at the time of rising and falling of the phase voltage of the switching unit 5. With this additional impedance, a current corresponding to the equivalent impedance 4 can always flow, and as a result, the prevention device 1 capable of generating the same and inverted voltage as the phase voltage flowing to the motor 13 can be obtained, and more accurate. Become. Additional impedance 37,
38 is an impedance equivalent to the main body, while leakage impedances 34, 35 and 36 are LCR circuits for passing transient current.

The operation of FIG. 23A will be described with reference to FIG. FIG. 23 (b) Transistor 30 when 1 → 2
Changes from on to off. When 2 → 3, the transistor 31 turns off → on. At this time, the phase voltage Uanti
Changes from H to L at the timing of the dotted line or the solid line depending on the direction of the current flowing through 37 and 38. Due to this voltage change, a cancel current flows through 34, 35, and 36. Here, in order to completely cancel the main body leakage current, the value of each impedance is set to a value completely equivalent to the main body. In the compressor motor of the room air conditioner, 38 is several to several tens mH, 37
Is several to several tens of ohms, 34 is several to several tens of k ohms, 3
5 is several to several tens of mH, and 36 is several thousand to tens of thousands of pF. In the case of 3 → 4 → 5, the logic is reversed and the transistor 31
Is turned on → off, and the transistor 30 is turned off → on. At this time, the phase voltage Uanti changes from L → H at the timing of the dotted line or the solid line depending on the direction of the current flowing through 37 and 38.
Becomes At this time, a cancel current having exactly the same magnitude as above and flowing in the opposite direction flows. The operation is exactly the same for the other phases.

Embodiment 12 FIG. FIG. 24A shows a circuit of a switching unit and a main body leakage impedance equivalent impedance unit of the earth leakage prevention device according to one embodiment of the present invention. 40 is a transistor 41, 43 is a resistor, 42 is a diode, 44 is a coil, and 45 is a capacitor. The main body leakage impedance equivalent impedance 4 and the switching unit of the first to eleventh embodiments are shown in FIG.
The same effect can be obtained with such a configuration. With this configuration, the transistor switches so as to perform a voltage change opposite to the main body phase voltage change.

With this configuration, the number of components in the switching section is reduced, and a more inexpensive earth leakage prevention device than in the first to eleventh embodiments can be obtained. That is, the capacitor 44
And so on, a cancel current flows as shown in FIG.

Each phase terminal point of main body 1 and equivalent impedance It is sufficient that point A in FIG. 23 (a) is the inversion voltage of the main body. In order to obtain this, 37 and 38 are provided in FIG. The operation of FIG. 24A will be described with reference to FIG. 1 →
At 2, the transistor 40 changes from off to on. At this time, the phase voltage Uanti changes from H to L. Due to this voltage change, the cancel current flows in the order of 45 → 44 → 43 → 40. Here, in order to completely cancel the main body leakage current, the value of each impedance is set to a value completely equivalent to the main body. 4 for the air conditioner compressor motor
1, 43 are several to several tens of k ohms, 44 is several to several tens of meters
H and 45 are several thousand pF to tens of thousands pF. In the case of 2 → 3, the logic is reversed and the transistor 40 is turned on → off.
At this time, the phase voltage Uanti changes from L to H. At this time, a cancel current having exactly the same magnitude as above and flowing in the opposite direction passes through and flows in the order of 41 → 42 → 44 → 45. The operation is exactly the same for the other phases. In the above circuit, the transistor 40 is a switching means that is opened and closed at a predetermined timing, and the resistances of the resistors 41 and 43 are the same.
The diode 42 is provided to change the path.

Embodiment 13 FIG. The same effect can be obtained even if the main body leakage impedance equivalent impedance 4 and the switching unit according to the first to twelfth embodiments of the invention are configured as shown in FIG. At this time, the voltage change of each transistor of the switching unit is smoothed.

As described above, the smooth switching operation of the transistor without using the coil reduces the number of parts of the switching section, and a more inexpensive earth leakage prevention device than the first to twelfth embodiments can be obtained. FIG. 25 shows FIG.
The operation is the same as in FIGS.
4, 35 coils are omitted. Even with the circuit in which L is omitted, there is additional impedance, and the coil, which is the most expensive component, can be omitted with a slight reduction in effect.

Embodiment 14 FIG. FIG. 26 shows a circuit of a switching section and a main body leakage impedance equivalent impedance section of the earth leakage prevention device according to one embodiment of the present invention. In FIG. 26, reference numeral 46 denotes a capacitor. The same effect can be obtained even if the main body leakage impedance equivalent impedance 4 and the switching unit of the first to twelfth embodiments are configured as shown in FIG. At this time, the voltage change of each transistor of the switching unit is smoothed, and the bus voltage is set to be lower than the bus voltage of the main body. FIG. 27 shows operation waveforms.

As described above, the switching of the transistor is smoothly performed without using the coil and the resistor, and the bus voltage is lower than the bus voltage of the main body. On the other hand, a more inexpensive earth leakage prevention device can be obtained. The impedances 37 and 38 of each phase are summarized at the neutral point 80.

Embodiment 15 FIG. FIG. 28 shows a circuit of the switching unit and the main body leakage impedance equivalent impedance unit of the earth leakage prevention device according to one embodiment of the present invention. In the present embodiment, the configuration is such that the coils and the resistance of the equivalent leakage impedance portion of the main body are reduced as compared with the eleventh and twelfth embodiments.

As described above, by reducing the number of components of the coil and the resistor, an inexpensive earth leakage prevention device can be obtained compared to the eleventh and twelfth embodiments. FIG. 28 shows components other than the capacitors in FIGS. 23 and 24 which are shared. If the phase voltages do not change at the same time for the three phases, components 54, 55 and 56 can be shared. This operation is as shown in FIG.

Embodiment 16 FIG. FIG. 29 shows a circuit of the switching unit and the drive unit of the earth leakage prevention device according to one embodiment of the present invention. Reference numeral 60 denotes a capacitor, and 61 denotes a resistor. These are integration circuits that drive the switching unit smoothly. When this driving unit is applied to the first to fifteenth embodiments, the same effect can be obtained even if the value of the coil is lowered when a coil is present in the main body leakage impedance equivalent impedance unit. In addition, since the operation of the transistor is smoothed in the case without a coil, the waveform of the cancel current becomes closer to the leakage current waveform, and the cancel effect is enhanced. FIG. 30 shows the operation of each unit at this time.

With the coil, the value of the coil is reduced, so that a more inexpensive device with no coil can be obtained. FIG. 29 shows an example in which the transistor of the switching unit, which had been performing the switching operation in the previous embodiments, is operated as an amplifier so that the same cancel current can be obtained without the equivalent impedance. ,
The equivalent impedance section can be integrated into a single chip without external components.

Embodiment 17 FIG. In the present embodiment, the value of each element of the main body leakage impedance equivalent impedance 4 of the eleventh to sixteenth embodiments is made variable. FIG.
Shows this for the eleventh and twelfth embodiments. In the present embodiment, the main body leakage impedance Equivalent impedance 4 is made variable, so that the main body load leakage impedance 8 due to aging, manufacturing variations, changes in operating conditions, manufacturing variations, etc., and the load leakage impedance of the earth leakage prevention device. The deviation of the equivalent impedance 4 can be corrected. The operation in FIG. 31 is obtained based on FIG. At this time, each element has a variable impedance that can be electronically controlled. Further, the values of the respective parts may be used for adjustment at the time of shipment for adjustment of variation in leakage impedance due to manufacturing variation of the compressor. If used only for adjustment at the time of shipment, a normal variable impedance element may be used.

As described above, since the configuration can be realized without using expensive and large components such as a leakage prevention transformer, an inexpensive and small leakage prevention device can be obtained. In addition, a highly reliable earth leakage prevention device that responds to aging, changes in operating conditions, and manufacturing variations can be obtained.

Embodiment 18 FIG. FIG. 32 shows a configuration diagram of an earth leakage prevention device according to an embodiment of the present invention. In the present embodiment, the load 13 is a three-phase DC brushless motor driven by a three-phase 180 ° conduction system.

FIGS. 33A and 33B show voltage / current waveforms of various parts of the present embodiment. FIG. 33E shows the output voltage U of the U-phase of the main body, FIG. W-phase output voltage W, (h) is a three-phase total leakage current, (i) is a voltage Manti applied to impedance M of the leakage prevention device,
(J) is a cancel current caused by the voltage fluctuation of Anti. The horizontal axis is the time axis.

FIG. 3 shows the operation of the earth leakage prevention device of this embodiment.
This will be described with reference to FIGS. (E), (f), (g),
As shown in (h), the electric charge charged to the capacitance component of the load leakage impedance 8 is leaking due to the switching of the phase current in the leakage current from the compressor motor.
On the other hand, in the earth leakage prevention device according to the present embodiment, the switching circuit 5 is driven from the control information of the main body to generate a voltage as shown in (i) by applying a voltage having a phase opposite to the phase voltage of the main body, thereby generating a load leakage impedance. The leakage current is prevented by applying a current reverse to the leakage current of the main body as shown in FIG.

At the same time, with a load in which the phase voltage does not change, the number of phases of each part of the protection device can be made smaller than the number of phases of the load, and the number of parts is reduced, so that an inexpensive leakage prevention device is obtained. That is, as shown by the dotted line in FIG. 33, it is sufficient to obtain a cancel current obtained by adding the applied voltage Manti to the equivalent impedance which is one series impedance, and the circuit cost can be reduced. The phase of the voltage Manti can be obtained by ANDing the phase voltage change of each phase voltage. Note that a load whose phase voltage does not change at the same time basically does not change at the same time in a three-phase inverter without modulation as shown in FIG. However, two phase voltages change at the same time as two-phase modulation is applied, and three phase voltages change at the same time as three-phase modulation is applied. When two-phase modulation is the mainstream for both the induction motor and the brushless motor, actually two circuits are optimal for three phases. However, in this embodiment, one circuit is shown with a three-phase load in order to clarify the difference from the other.

As described above, the total number of switches, that is, the number of transistors, the number of L, C, and R elements can be made smaller than the number of phases of the inverter. That is, since the number of phases of the prevention device is reduced with respect to the total number of phases of the inverter, an inexpensive leakage prevention device can be obtained. Although all of the above embodiments have been described with respect to a three-phase load, it goes without saying that any single-phase and all-phase loads can be used irrespective of the type and energization method of the motor as long as the switching timing can be performed simultaneously. Absent. In addition, although the description has been given of the motor neutral point non-grounding, it is obvious that the neutral point non-grounding method may be used.

Although the above description has been directed to preventing leakage of the compressor, it goes without saying that the invention can be used to prevent leakage of any load driven by the inverter.

The above embodiment can be realized in the same IC. In the case where the leakage prevention device is included in the IC, a technique for mounting the high voltage and the low voltage at the same time is required. However, since this technique has been put into practical use as an HVIC, it is easy to realize.

By realizing it in the same IC, a very small and inexpensive earth leakage prevention device can be obtained. As described above, since the power supply is shared by the inverter and the prevention device as in the invention of FIG. 1, it is possible to inexpensively and surely generate the opposite phase.
In each of the embodiments, the size can be reduced without using a transformer as in the conventional example.

Embodiment 19 FIG. FIG. 34 is a circuit configuration diagram of a switching unit and an equivalent impedance unit equivalent to an impedance for earth leakage in the earth leakage prevention device.
FIG. 34 is the same as FIG. 24, and is substantially the same as the description of Embodiment 12 of the present invention. FIG. 35 is an operation timing chart of each part of the one phase. FIG. 36 is an overall configuration diagram of the leakage prevention device of the present invention. In FIG. 34, 160 is a transistor, 161 is a diode, 162 and 163 are resistors, 16
4 is a capacitor and 165 is a coil. 34 and 35
The operation will be described with reference to FIG. When 1 → 2, the transistor 160 is turned off → on. At this time, the phase voltage Uant
i becomes H → L. At this time, a cancel current for canceling the leakage current of the main body flows through a path of 165 → 164 → 163 → 160. Here, in order to completely cancel the leakage current on the main body side, each impedance has a value completely equivalent to that of the main body. In the case of 2 → 3, the logic is reversed and the transistor 160 is turned on → off. At this time, the phase voltage Uanti becomes L →
H. At this time, the cancel current having the magnitude completely opposite to that of 1 → 2 and having a different direction is 162 → 161 → 164 → 16
It flows in the path of 5. This is exactly the same operation for the other phases. In this way, a voltage in the opposite phase of the switching of the main body is applied to the impedance to generate a current that cancels the leakage current, thereby preventing the leakage current.

In this leakage prevention device, as shown in FIG. 35, while the transistor 160 is on, 16
The power supply voltage is fully applied to the resistor No. 2 and a current not related to the cancel current continues to flow. When the impedance of the resistance component of the leakage impedance of the main body is large, the power loss in the resistor 62 is small, and a small resistor may be used to withstand heat generation. That is, the equivalent impedance section is designed to match the leakage impedance (resistance) of the main body. When the capacity of the main body, that is, the compressor is reduced, the size of the object is reduced, and the leakage current is reduced, the resistor 162 is small and is economical.

However, as the size of the compressor increases, the heat generated by the resistor 162 increases, which increases the resistance and becomes uneconomical. Therefore, this measure will be described in the following example.

Embodiment 20 FIG. FIG. 36 shows a configuration diagram of an earth leakage prevention device according to an embodiment of the present invention.
Denotes a configuration of a leakage prevention device, 2 denotes a configuration of a main body, and 3 denotes a commercial power supply. 1 is a leakage prevention device, 4 is an impedance equivalent to the leakage impedance 8 of the main body load, 5 is a switching unit for applying a voltage to the load leakage impedance equivalent impedance of 4, 6 is a driving unit for driving the 5 switching unit, and 7 is a driving unit. The control unit generates a switching pattern. The power supply of the switching unit 5 of the earth leakage prevention device uses the output of the main converter 12. In the present embodiment, the control unit 9 of the main unit and the control unit 7 of the leakage prevention device are realized on the same microprocessor, and the control is performed on a program incorporated in the microprocessor. The drive unit 6 and the switching unit 5 are composed of electronic components having a low current capacity (about 500 mA or less). This is an example in which the present invention is applied to a three-phase compressor motor.

FIG. 37 is a circuit configuration diagram of a switching unit and an equivalent impedance unit equivalent to the impedance for earth leakage in the earth leakage prevention device according to the present embodiment. In FIG. 37, 120 and 121 are transistors, 122 is a diode, 123 is a diode, and 124 is a resistor, 125 is a capacitor,
126 is a coil.

FIG. 38 is an operation timing chart of each part in the present embodiment. (A) U-phase output voltage U of the main body,
(B) is a leakage current caused by the voltage fluctuation of U, (c) is a voltage Uanti applied to the U-phase portion of the impedance 4 of the earth leakage prevention device, and (d) is a cancel current caused by the voltage fluctuation of Uanti. . (E) and (f) show the on and off states of 120 and 121, respectively. The horizontal axis is the time axis.

FIG. 3 shows the operation of the earth leakage prevention device of the present embodiment.
This will be described with reference to FIGS. The explanation will focus on the U phase. When 1 → 2 in FIG. 38B, the transistor 120 is turned off → on. At this time, the phase voltage Uanti becomes H →
L. At this time, a cancel current that cancels out the leakage current of the main body flows through a path of 126 → 125 → 124 → 122 → 120. Here, in order to completely cancel the leakage current on the main body side, each impedance has a value completely equivalent to that of the main body. In the case of 2 → 3, the logic is reversed and the transistor 120 is turned on → off. At this time, the transistor 121 changes from off to on, and the transistor 121 is turned on while the cancel current is flowing.
Is closed, the phase voltage Uanti changes from L to H. At this time, a cancel current having a magnitude completely opposite to that of 1 → 2 and having a different direction flows in a path of 121 → 124 → 125 → 126.
This is exactly the same operation for the other phases. In this way, a voltage opposite to the switching phase of the main body is applied to the impedance to generate a current that cancels the leakage current, thereby preventing the leakage current. Here, the resistor 123 drives the transistor 121 and has a large value regardless of the resistance component of the equivalent impedance. The diode 122 prevents a reverse voltage between the base and the emitter of the transistor 121.

By adopting such a configuration, the present device can be configured without any portion that generates a large power loss even for a device having a small resistance component of the leakage impedance, and an inexpensive, small, and efficient leakage prevention device can be provided. can get. Also, since it is composed of small-capacity components, it can be made into an IC.
If C is used, the cost can be further reduced and the size can be reduced.

Embodiment 21 FIG. FIG. 36 shows a configuration diagram of an earth leakage prevention device according to an embodiment of the present invention.
Denotes a configuration of a leakage prevention device, 2 denotes a configuration of a main body, and 3 denotes a commercial power supply. 1 is a leakage prevention device, 4 is an impedance equivalent to the leakage impedance 8 of the main body load, 5 is a switching unit for applying a voltage to the load leakage impedance equivalent impedance of 4, 6 is a driving unit for driving the 5 switching unit, and 7 is a driving unit. The control unit generates a switching pattern. The power supply of the switching unit 5 of the earth leakage prevention device uses the output of the main converter 12. In the present embodiment, the control unit 9 of the main unit and the control unit 7 of the leakage prevention device are realized on the same microprocessor, and the control is performed on a program incorporated in the microprocessor. The drive unit 6 and the switching unit 5 are composed of electronic components having a low current capacity (about 500 mA or less). This is an example in which the present invention is applied to a three-phase compressor motor.

FIG. 39 is a circuit diagram of the switching section and the equivalent impedance section equivalent to the impedance for earth leakage of the earth leakage prevention device according to the present embodiment. FIG. 39 shows 140 and 141 transistors, 142 a resistor,
143 is a capacitor, and 144 is a coil.

FIG. 40 is an operation timing chart of each part in the present embodiment. FIG. 40A shows the output voltage U of the U phase of the main body.
(B) is a leakage current caused by the voltage fluctuation of U, (c) is a voltage Uanti applied to the U-phase portion of the impedance 4 of the earth leakage prevention device, and (d) is a cancel current caused by the voltage fluctuation of Uanti. . (G) and (h) show the on and off states of the transistors 140 and 141, respectively. The horizontal axis is the time axis.

FIG. 3 shows the operation of the earth leakage prevention device of the present embodiment.
This will be described using 6, 39, and 40. The explanation will focus on the U phase. When 1 → 2, the transistor 141 is turned off → on,
The transistor 140 changes from on to off. At this time, the phase voltage Uanti changes from H to L. At this time, the cancellation current for canceling the leakage current of the main body is 144 → 143 → 142.
→ It flows along the path of 141. Here, in order to completely cancel the leakage current on the main body side, each impedance has a value completely equivalent to that of the main body. In the case of 2 → 3, the logic is reversed and the transistor 141 is turned on → off. Transistor 14
At this time, 0 changes from off to on, and the phase voltage Uanti changes from L to H. At this time, the cancel currents having magnitudes completely opposite to those of 1 → 2 and having different directions are 120 → 142 → 143 →
It flows on the 144 path. This is exactly the same operation for the other phases. In this way, a voltage opposite to the switching phase of the main body is applied to the impedance to generate a current that cancels the leakage current, thereby preventing the leakage current. The switching element 140 is an NPN type, and 141 is a PNP type.

By adopting such a configuration, the present device can be configured without a portion that generates a large power loss even in a device having a small resistance component of the leakage impedance, and an inexpensive, small, and efficient leakage prevention device can be provided. can get. Also, since the element is configured by combining PNP and NPN, and is configured by small-capacity parts, it can be integrated into an IC.
If it is made smaller, it can be further reduced in cost and size.

[0104]

As described above, according to the first aspect of the present invention, an inexpensive, compact and highly versatile earth leakage prevention device can be obtained.

According to the second aspect of the present invention, leakage can be reliably prevented by a small device that can be added to the inverter device. Further, since the switching pattern is generated based on the control information, the driving unit can be formed by the same circuit (microcomputer), and the reliability is high.

According to the third aspect of the present invention, since the switching pattern is configured to generate a current having a phase opposite to that of the ground leakage current, a cancel current close to the leakage current can be generated. A device is obtained.

According to the fourth aspect of the present invention, the leakage current can be detected and controlled, and detailed measures can be taken, and a highly reliable leakage prevention device can be obtained.

According to the fifth aspect of the present invention, since the control signal is changed based on the information of the ground leakage, a wide-range switching operation is possible, and a more reliable leakage prevention device can be obtained.

According to the sixth aspect of the present invention, since the switching drive signal is changed on the basis of the information of the ground leakage, a reliable switching device can be obtained.

According to the seventh aspect of the present invention, the impedance is changed and adjusted based on the information of the ground leakage, so that a highly reliable and accurate leakage prevention device with reduced current can be obtained.

The present invention according to claim 8 provides the variable power supply based on the ground leakage information and changes the applied voltage, so that it is possible to reliably prevent leakage according to the amount of leakage.

According to the ninth aspect of the present invention, since information on switching is obtained from the inverter driving section, an inexpensive, highly versatile device having a reliable control operation can be obtained.

According to the tenth aspect of the present invention, since the switching is performed by directly using the switching information of the inverter, the influence of noise and the like can be reduced, the leakage can be more reliably prevented, and a highly versatile device can be obtained. In addition, the cancellation current easily matches the leakage current, and a highly reliable device that is resistant to aging can be obtained.

According to the eleventh aspect of the present invention, since the control unit includes the delay means, it is possible to accurately prevent the electric leakage. In particular, since the characteristics and variations of elements that delay signals, such as switching elements and photocouplers, can be adjusted with delay, an apparatus that can produce a more accurate cancel current can be obtained.

According to the twelfth aspect of the present invention, since the delay section is provided in the driving section, switching can be effectively and reliably delayed, and a highly reliable device can be obtained.

According to the thirteenth aspect of the present invention, since the impedance section is provided with the configuration of each element, the device can be obtained with a simple configuration for maintenance.

According to the fourteenth aspect of the present invention, since the leakage impedance circuit is simplified, the size of the device can be reduced.

The present invention according to claim 15 can be constituted by a simplified equivalent circuit, and an earth leakage prevention device can be obtained with a simple structure.

According to the present invention, the impedance can be made simpler and an inexpensive device can be obtained.

According to the seventeenth aspect of the present invention, by sharing parts, an impedance can be obtained with less electric parts and an inexpensive apparatus can be obtained.

According to the eighteenth aspect of the present invention, since an integrating circuit is used in the driving section, even if a coil is not used, a delay of a leakage current with respect to a sudden change in phase voltage can be made even if the coil is insufficient. An inexpensive and small leakage prevention device can be obtained.

According to the nineteenth aspect of the present invention, since the value of each element of the impedance can be changed, a highly reliable device capable of coping with a change in the leakage current characteristic can be obtained.

According to the twentieth aspect of the present invention, the leakage prevention device can be obtained with a small number of parts, and is economical.

According to the twenty-first aspect of the present invention, the components of the device can be integrated, mass production is easy and inexpensive, and the device can be miniaturized and mounted anywhere.

According to the present invention, even if the leakage current increases as in the case where the size of the compressor increases, the leakage can be prevented with a small device.

According to a twenty-third aspect of the present invention, the PNP and the N
Since the leakage prevention device can be configured by combining the PNs, components can be integrated and a remarkably small device can be obtained.

According to the twenty-fourth aspect of the present invention, since the equivalent current is generated to cancel the ground current, the leakage can be prevented easily and inexpensively.

According to the twenty-fifth aspect of the present invention, it is possible to follow a change in leakage current, and to obtain a highly accurate method for preventing leakage.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a leakage prevention device for an inverter driving load according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram of each part of the leakage prevention device for an inverter driving load according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a leakage prevention device for an inverter driving load according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a leakage prevention device for an inverter driving load according to a third embodiment of the present invention.

FIG. 5 is an explanatory diagram of a leakage current detector according to the present invention.

FIG. 6 is an explanatory diagram showing a timing chart of a drive signal and a leakage current according to the present invention.

FIG. 7 is a flowchart showing signal correction according to the present invention.

FIG. 8 is a configuration diagram of an earth leakage prevention device for an inverter driving load according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram of a circuit that performs correction according to the present invention.

FIG. 10 is a configuration diagram of a leakage prevention device for an inverter driving load according to a fifth embodiment of the present invention.

FIG. 11 is an explanatory diagram of a cancel current waveform according to the present invention.

FIG. 12 is an explanatory diagram showing a leakage current according to the present invention.

FIG. 13 is a flowchart showing an algorithm relating to correction of the present invention.

FIG. 14 is a configuration diagram of an earth leakage prevention device for an inverter driving load according to a sixth embodiment of the present invention.

FIG. 15 is a flowchart showing an algorithm relating to correction of the present invention.

FIG. 16 is a configuration diagram of a leakage prevention device for an inverter driving load according to a seventh embodiment of the present invention.

FIG. 17 is an explanatory view of a cross connection according to the present invention.

FIG. 18 is a configuration diagram of an earth leakage prevention device for an inverter driving load according to an eighth embodiment of the present invention.

FIG. 19 is an explanatory diagram showing a timing chart of information and output of the present invention.

FIG. 20 is a flowchart of the control unit of the earth leakage prevention device according to Embodiment 9 of the present invention.

FIG. 21 is a circuit diagram of a drive unit and a switching unit of an earth leakage prevention device according to Embodiment 10 of the present invention.

FIG. 22 is an explanatory diagram of a delay time according to the present invention.

FIG. 23 is a diagram illustrating a switching unit, an equivalent impedance circuit, and an operation of an earth leakage prevention device according to Embodiment 11 of the present invention;

FIG. 24 is a diagram illustrating a switching unit, an equivalent impedance circuit, and an operation of an earth leakage prevention device according to a twelfth embodiment of the present invention.

FIG. 25 is a circuit diagram of a switching portion and a main body leakage impedance equivalent impedance of an earth leakage prevention device according to Embodiment 13 of the present invention.

FIG. 26 is a circuit diagram of a switching unit and a main body leakage impedance equivalent impedance of an earth leakage prevention device according to Embodiment 14 of the present invention.

FIG. 27 is an explanatory diagram showing operation waveforms of the present invention.

FIG. 28 is a circuit diagram of a switching section and a main body leakage impedance equivalent impedance of an earth leakage prevention device according to Embodiment 15 of the present invention.

FIG. 29 is a circuit diagram of a driving unit and a switching unit of an earth leakage prevention device according to Embodiment 16 of the present invention.

FIG. 30 is an explanatory diagram showing operation waveforms of the present invention.

FIG. 31 is a circuit diagram of a switching section and a main body leakage impedance equivalent impedance of an earth leakage prevention device according to Embodiment 17 of the present invention.

FIG. 32 is a configuration diagram of an earth leakage prevention device according to Embodiment 18 of the present invention.

FIG. 33 is a waveform chart of each part of the earth leakage prevention device according to Embodiment 18 of the present invention.

FIG. 34 is a circuit diagram of a leakage impedance with respect to the ground equivalent to a switching unit and a load of an earth leakage prevention device according to a nineteenth embodiment of the present invention.

FIG. 35 is an operation timing chart of the earth leakage prevention device according to the nineteenth embodiment of the present invention.

FIG. 36 is a configuration diagram of an earth leakage prevention device according to a nineteenth embodiment of the present invention.

FIG. 37 is a circuit diagram of leakage impedance with respect to the ground equivalent to the switching unit and the load of the leakage prevention device according to the nineteenth embodiment of the present invention.

FIG. 38 is an operation timing chart of each unit of the earth leakage prevention device according to the nineteenth embodiment of the present invention.

FIG. 39 is a circuit diagram of a leakage impedance with respect to the ground equivalent to the switching unit and the load of the leakage prevention device according to Embodiment 20 of the present invention.

FIG. 40 is an operation timing chart of each unit of the earth leakage prevention device according to the twentieth embodiment of the present invention.

FIG. 41 is a circuit configuration diagram of a conventional earth leakage prevention device.

[Explanation of symbols]

1 Leakage prevention device configuration, 2 main body configuration, 4 load leakage impedance equivalent impedance unit, 5 leakage prevention device switching unit, 6 leakage prevention device drive unit, 7 leakage prevention device control unit, 8 main unit load leakage impedance, 9 main unit Control unit, 10 main unit drive unit, 11 main unit switching unit, 12 converter, 15 DC power supply, 16
Leakage current detector, 17 variable power supplies, 20 variable resistors,
21 capacitor, 22 inverting circuit, 30, 31 transistor, 32, 33 diode, 34, 37 resistor, 35, 38 coil, 36 capacitor, 40 transistor, 41, 43 resistor, 42 diode, 4
4 coil, 45, 46 capacitor, 50, 53 capacitor, 54 diode, 51, 55 resistor, 5
2,56 coil, 70, 73, 76 variable resistance, 7
1,74 variable coil, 72,75 variable capacitor,
80 neutral point, 125,143,164 capacitor,
120, 121, 140, 141, 160 Transistor, 122, 161 diode, 123, 124, 14
2,162,163 resistance, 126,144,165
coil.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H007 AA17 BB06 CA01 CB05 DA03 DA06 DC02 EA02 5H576 AA10 BB10 CC05 DD02 EE11 HA02 HB02 JJ25 LL22

Claims (25)

[Claims] 1. A DC power supply of an inverter or a separately provided DC power supply, a switching means for switching a DC from the DC power supply to convert it into an AC, and an AC generated by the switching means is applied to one end and the other end is applied. An impedance unit to be grounded; and a control unit connected to a control device that generates a signal of an AC voltage applied to the drive load by the inverter, and generates a voltage signal having a phase opposite to that of the AC voltage and drives the switching unit. A leakage prevention device, comprising: an impedance unit having an impedance amount for generating a current having a phase opposite to a ground leakage current of a load driven by an inverter. 2. An impedance unit having an impedance corresponding to an impedance of a load driven by an inverter that generates an alternating current by switching a direct current, and switches a direct current from a direct current power source of the inverter or another direct current power source. A switching unit that energizes the impedance, a driving unit that drives the switching unit, and a control unit that generates a switching pattern of the switching unit based on control information of a control unit of the inverter and supplies the switching pattern to the driving unit. Characteristic leakage prevention device. 3. The leakage prevention device for an inverter driving load according to claim 2, wherein the switching pattern of the switching unit generates a current having a phase opposite to that of the ground leakage current of the load. 4. A control circuit for generating an AC voltage or changing an impedance amount of an impedance unit according to information of the leakage current detection unit for detecting information of ground leakage of the inverter driving load. The earth leakage prevention device according to claim 1 or 2, wherein 5. The apparatus according to claim 2, further comprising: a leakage current detection unit that detects information on ground leakage of an inverter driving load, and supplies leakage information to the control unit to change an operation of the switching unit. The leakage prevention device according to claim 3. 6. The switching device according to claim 2, further comprising a leakage current detection unit for detecting information of ground leakage of an inverter driving load, providing leakage information to the driving unit, and changing an operation of the switching unit. The leakage prevention device according to claim 3. 7. The apparatus according to claim 2, further comprising: a leakage current detection unit that detects information of ground leakage of an inverter driving load, and supplies leakage information to the impedance unit to change the amount of the impedance. Item 7. The leakage prevention device according to Item 3. 8. The power supply of the switching unit is a variable power supply,
4. The leakage prevention device according to claim 2, further comprising: a leakage current detection unit configured to detect ground leakage information, providing leakage information to the variable power supply, and changing a bus voltage of the switching unit. apparatus. 9. An impedance section having an impedance corresponding to an impedance of the load driven by the inverter against earth leakage, a switching section for switching a DC power supply and supplying current to the impedance, a driving section for driving the switching section, and a driving section for the inverter. An electric leakage prevention device comprising: a control unit that generates a switching pattern of the switching unit based on driving information of a driving unit and supplies the switching pattern to the driving unit. 10. An impedance section having an impedance corresponding to an impedance of the load driven by the inverter against earth leakage, a switching section for switching a DC power supply and supplying current to the impedance, a driving section for driving the switching section, and a driving section for the inverter. An earth leakage prevention device comprising: a control unit that generates a switching pattern of the switching unit based on switching information of the switching unit and supplies the switching pattern to the driving unit. 11. The leakage prevention device according to claim 2, wherein the control unit includes a delay unit. 12. The leakage prevention device according to claim 2, wherein the drive unit includes a delay unit. 13. A device according to claim 1, further comprising a resistor and a coil in series between at least a capacitor between each phase of the impedance section and the ground, and in series between each phase and a place where the phases are combined. An earth leakage prevention device according to claim 12. 14. A switching means connected to one end of a DC power supply for generating a voltage having a phase opposite to a voltage of each phase of an inverter driving load, and a switching means provided between each switching means and the ground to generate a transient current. A first leakage impedance circuit, and a second leakage impedance circuit provided between the other of the DC power supply and the ground to generate a transient current having a phase opposite to that of the transient current. 13. The leakage prevention device according to claim 1, wherein a part of elements constituting a circuit is shared. 15. A transistor connected to each phase of the switching unit, a diode connected in parallel with a resistor between each phase of the impedance unit and the ground, and at least a capacitor in series, and between each phase and a bus of the switching unit. 13. The leakage prevention device according to claim 1, wherein the leakage prevention device has a resistance. 16. The leakage prevention device according to claim 1, wherein a resistor, a capacitor, and a coil are connected in series between each phase of the impedance section and the ground. 17. The earth leakage according to claim 13, wherein a resistor, a coil, or a diode connected in series between each phase of the impedance section and the ground and the bus is shared. Prevention device. 18. The leakage prevention device according to claim 2, wherein an integration circuit is used in the driving section. 19. The leakage prevention device according to claim 1, wherein a value of each element of the impedance section is variable. 20. The leakage prevention device according to claim 1, wherein the total number of switching operations of the switching unit is N or less for an N-phase load. 21. The electric leakage device according to claim 1, wherein a control device for driving and controlling an impedance unit and a switching unit for applying a voltage to the impedance unit are integrated in the same IC. Prevention device. 22. A first switching means connected to one end of the DC power supply for generating a voltage having a phase opposite to the voltage of each phase of the inverter driving load, and generating a transient current from the ground to the first switching means. The first provided to let
A leakage impedance circuit, a second switching means connected to the other end of the DC power supply, and provided to generate a transient current having a phase opposite to the transient current from the second switching means to the ground.
13. The leakage prevention device according to claim 1, wherein at least a part of the elements constituting the first and second leakage impedance circuits is common to the first and second leakage impedance circuits. 23. A PNP-type switching element connected to one end of a DC power supply, an NPN-type switching element connected to the other end of the DC power supply, and an inverter connected to the ground from between the two switching elements. The earth leakage prevention device according to any one of claims 1 to 12, further comprising: a ground leakage impedance circuit equivalent to a driving load. 24. A step of applying an AC voltage generated by an inverter to a driving load, a step of generating a voltage whose phase is inverted in synchronization with the AC voltage, and flowing when the AC voltage is applied to the driving load. A step of setting an impedance that flows when a current equivalent to a ground leakage current is applied to the inversion voltage, and a step of grounding the driving load and the impedance so that the ground leakage current and the equivalent current can be canceled. Leakage prevention method for inverter drive load provided. 25. The method according to claim 24, further comprising the step of: changing a voltage applied to the impedance to follow a change in a leakage current leaking from the inverter driving load to the ground. Prevention method.