JP3829212B2 - Inverter device and refrigeration device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inverter device and a refrigeration apparatus including the inverter device.
[0002]
[Prior art]
The refrigeration apparatus includes a compressor driven by an electric motor, a condenser that cools and condenses refrigerant gas compressed by the compressor, a pressure reducing valve that decompresses liquid refrigerant discharged from the condenser, and a pressure reducing valve. It has a refrigeration cycle formed by an evaporator that evaporates the liquid refrigerant that is introduced and returns it to the compressor as a refrigerant gas, and includes an inverter device that controls the operating frequency of the induction motor at a variable speed, and is refrigerated and refrigerated. Or it is used for air conditioning.
[0003]
The inverter device converts, for example, DC power converted from an AC commercial power supply by a converter circuit or the like, or DC power supplied from a battery or the like into AC power having a desired frequency, and is a power semiconductor (in other words, Switching element), for example, an inverter circuit in which a three-phase bridge is connected, and a control circuit such as a microcomputer that performs control called switching for alternately turning on and off the switching element in the inverter circuit. It is prepared for.
[0004]
As a configuration of such an inverter device, for example, a first board on which a converter circuit and an inverter circuit are mounted, a second board on which a microcomputer that performs switching control of the inverter circuit, a terminal block, and an inrush suppression resistor are provided. The inverter basic unit is configured to be separated into an inverter basic unit composed of a third substrate on which a smoothing capacitor is mounted and an I / O block unit that manages an input / output interface in microcomputer processing, and the inverter basic unit is changed. There has been proposed one that makes it easy to change the specification only by changing the I / O block (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-41943 (page 2-4, FIG. 1)
[0006]
[Problems to be solved by the invention]
By the way, the power semiconductor mounted in the inverter device generates heat by energization, and when the temperature becomes high, problems such as shortening of the life or breakage occur. For this reason, in general, fins and the like are attached to urge heat dissipation so that the temperature of the power semiconductor becomes a temperature suitable for use. However, if the temperature of the power semiconductor is relatively high due to circuit integration or higher carrier frequency, fins with higher heat dissipation performance, that is, larger fins, are required as the temperature increases. There is a problem that the whole becomes large. In particular, an inverter device of a type formed by laminating a plurality of substrates has a problem that the arrangement position of each substrate is limited due to an increase in fins. Therefore, it is desired to keep the temperature of each power semiconductor within a certain range so that the fins need not be enlarged.
[0007]
The subject of the present invention is Immediately before driving the motor, an inverter circuit with a control for adjusting the rotor of the motor to the initial position by passing a direct current through the motor for a set time. It is to suppress the temperature rise of the power semiconductor.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention forms an inverter circuit. Bridged An inverter device comprising a plurality of power semiconductors and a control circuit for controlling on / off operation of each of the power semiconductors, wherein the inverter device converts the DC power supplied to the inverter circuit into AC power and supplies the AC power to the motor. Just before setting the motor, The power semiconductors of the upper and lower arms of one of the phases of a plurality of bridge-connected power semiconductors and the power semiconductors of the upper and lower arms of a phase different from the phase ON operation Switching pattern Fixed to The In addition to controlling the motor rotor to the initial position by passing a direct current through the motor, it should be fixed to the on-state every time the control is performed. Rotating power semiconductor switching pattern It is characterized by doing.
[0009]
That is, the present invention pays attention to the control for energizing any one of the power semiconductors to adjust the rotor of the motor to the initial position at the start of driving of the electric motor, and rotates the power semiconductor to be energized in the control. . As a result, even when the motor is frequently started and stopped, it is possible to avoid energization being distributed to each power semiconductor and concentration of heat generation, and it is possible to suppress the temperature of any of the power semiconductors from rising excessively. Therefore, the temperature of each power semiconductor becomes average, and each is kept at a relatively low temperature. Therefore, the fins need only have the ability to cool the relatively low temperature to a temperature suitable for use, and are reduced. be able to. Here, as the motor, for example, a three-phase induction motor or a permanent magnet synchronous motor in which a squirrel-cage conductor and a permanent magnet are provided on an iron core of a rotor (rotor) can be used.
[0010]
In addition, when the electric motor is driven, the control circuit fixes one of the power semiconductors in any phase to the on operation and the other power semiconductor to the off operation, and controls the on / off operation of the remaining power semiconductors. The phase to which the power semiconductor to which the on operation and the off operation should be fixed can be sequentially switched. For example, when the electric motor is a three-phase induction motor, so-called two-phase PWM control can be performed. As a result, the heat generation and loss of the power semiconductor with the fixed switching operation can be reduced and the size can be further reduced. In this two-phase PWM control, for example, the period during which switching is not performed is 1/3 of one cycle.
[0011]
Moreover, the inverter device of the present invention is mounted with a converter circuit that supplies alternating current power from an alternating current power source to direct current power to the inverter circuit, and a power semiconductor that constitutes the inverter circuit, and a radiating fin is provided on the opposite surface of the mounting surface. A first board to be mounted; a control circuit; a second board on which a current detection mechanism for detecting and inputting the current of the motor to the control circuit; and a terminal block of the motor; and various temperatures of the refrigeration cycle or A third substrate on which an interface connector to which a pressure signal is input and a photocoupler that transmits the signal input through the interface connector to the control circuit by an optical signal is mounted, and are stacked in order from the bottom. The first substrate, the second substrate, and the third substrate are stored, and the gel is filled up to the mounting surface of the power semiconductor of the first substrate. And a control circuit that monitors the state of the motor with the current input from the current detection mechanism and that is input via an interface connector and a photocoupler. The motor can be configured to perform variable speed control based on various temperatures or pressures.
[0012]
Thereby, the converter circuit and the inverter circuit are mounted on the same substrate (first substrate), and the control circuit for controlling the power semiconductor of the inverter circuit, the current detection mechanism for detecting the current of the motor, and the terminal block of the motor are provided. Since the mounted second substrate can be overlapped and brought close to each other, the wiring length of the portion where the possibility of noise generation is large can be shortened, and the cause of noise generation can be reduced.
[0013]
Further, for example, an interface connector to which signals of various temperature or pressure detection sensors of a refrigeration cycle that are easily affected by a compressor that requires a large current is input is mounted on the third board and is the uppermost part. And transmission to the control circuit by an optical signal, so that noise can be reduced. In addition, the control circuit can perform variable speed control of the electric motor based on various temperatures or pressures of the refrigeration cycle. For example, the heat dissipation of the inverter control device that varies depending on the outside air temperature, the heat exchanger, the blower, and the compressor state. It can correspond to characteristics.
[0014]
Furthermore, since the power semiconductor surface of the first substrate is filled with gel and the resin is sealed from the gel surface to the upper surface of the second substrate, the reliability of the power module ISPM itself can be improved. Furthermore, the microcomputer software or input / output interface that is the control circuit depends on the configuration of the refrigeration cycle, the refrigeration system and the inverter used in the system, the capacity of the air conditioner, the model of the store, the building multi, etc. When changing the hardware of the face, it can be easily handled by separating the uppermost third substrate. Even in this case, since the current values are arranged in descending order from the bottom surface of the case, the number of wirings can be reduced. In this case, an active circuit for improving the power factor can be mounted on the first substrate, and a mechanism for controlling the active circuit can be mounted on the second substrate.
[0015]
The inverter device includes a compressor driven by an electric motor, a condenser that cools and condenses the refrigerant gas compressed by the compressor, a pressure reducing valve that depressurizes liquid refrigerant discharged from the condenser, It can be mounted on a refrigeration apparatus including a refrigeration cycle formed by an evaporator that evaporates liquid refrigerant guided through a pressure reducing valve and returns the refrigerant to a compressor.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a refrigeration apparatus and an inverter apparatus to which the present invention is applied will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of an air conditioner using a refrigeration apparatus to which the present invention is applied. FIG. 2 is a circuit diagram showing a schematic configuration of an embodiment of an inverter device to which the present invention is applied. FIG. 3 is a perspective view illustrating the assembly configuration of the inverter device of the present embodiment. FIG. 4 is a perspective view of the inverter device of the present embodiment. FIG. 5 is a cross-sectional view showing a schematic configuration of the inverter device of the present embodiment. FIG. 6 is a flowchart showing control of the microcomputer of the inverter device of this embodiment. FIG. 7 is a graph illustrating the PWM control, showing the carrier wave eS, the voltage command eoU, and the control signals to the switching elements 38UP and 38UN. FIG. 8 is a graph illustrating control signals to the voltage commands eoU, eoV, eoW of each phase and the switching elements 38UP, 38UN, 38VP, 38VN, 38WP, 38WN, and illustrating the two-phase PWM control. FIG. 9 is a circuit diagram illustrating detailed configurations of the driver circuit 41 and the inverter circuit 33. FIG. 10 is a circuit diagram showing a modification of the present embodiment.
[0017]
As shown in FIG. 1, the air conditioner of this embodiment includes a compressor 1 that compresses a refrigerant, an indoor heat exchanger 3 and an outdoor heat exchanger 7 through which the refrigerant flows, and an expansion valve 5 that decompresses the refrigerant. And is configured. The compressor 1, the indoor heat exchanger 3, the expansion valve 5, and the outdoor heat exchanger 7 are sequentially connected in an annular manner by a refrigerant pipe 9 to form a refrigeration cycle in which the refrigerant circulates. The compressor 1 is driven by a dielectric motor 11 whose operating frequency is variably controlled in relation to the capacity required for the refrigeration cycle. The operating frequency of the motor 11, that is, the rotational speed of the compressor 1, is determined by the inverter device 13. It is controlled by.
[0018]
The compressor 1 includes a discharge port for discharging the refrigerant and a suction port for sucking the refrigerant. The discharge port is connected to the refrigerant pipe 9 via a four-way valve 15, and the suction port is connected to the accumulator 17 and the four-way valve 15. And connected to the refrigerant pipe 9. In the four-way valve 15, for example, during cooling operation, the gas refrigerant compressed by the compressor 1 is guided to the outdoor heat exchanger 7 (solid line in the figure), and during heating operation, the compressor 1 passes the accumulator 9 through the accumulator 9. The refrigerant in the heat exchanger 7 is configured to be switched so that the refrigerant is sucked (in the dotted line in the figure). In addition, the indoor heat exchanger 3 and the outdoor heat exchanger 7 are provided with blowers 19 and 21 for ventilating the surrounding atmosphere, respectively.
[0019]
In such an air conditioner, in addition to the rotation speed of the compressor 1 and switching of the four-way valve 15, the opening degree of the expansion valve 5 for adjusting the refrigerant flow rate or the expansion valve (not shown) provided in the outdoor unit, The number of rotations of the blowers 19 and 21 is controlled by the control device 23. The control device 23 detects, for example, an operation command signal from a remote controller that performs operation mode, temperature setting, a compressor discharge gas temperature, a suction temperature, a heat exchanger temperature, and a pressure as information for performing control. Etc. are entered. The control device 23 is connected to the inverter device 13 via an interface connector 51 (not shown in FIG. 1). For example, a suction pressure of a compressor, between the control device 23 and the inverter device 13, Compressor discharge pressure, compressor temperature, expansion valve opening, compressor current value, compressor frequency, outside air temperature, evaporator heat exchanger temperature, indoor / outdoor suction temperature, indoor / outdoor Information (hereinafter collectively referred to as operation information) such as the temperature blown out from the machine, the freezing temperature, the frequency required for the compressor, the temperature of the refrigerant pipe, and the set temperature is exchanged and controlled in cooperation. .
[0020]
Next, the configuration of the inverter device which is a characteristic part of the present embodiment will be described with reference to FIG. As shown in FIG. 2, the inverter device 13 is mainly mounted with a first board 27 on which a circuit for supplying power from the AC power supply 25 to the electric motor 11 is mounted and a circuit for controlling the first board 27. The second board 28 and a third board 29 on which a circuit for transmitting operation information between the second board 28 and the control device 23 is mounted.
[0021]
The first substrate 27 is connected to a single-phase AC power supply 25, converts the AC power from the single-phase AC power supply 25 into DC, an inverter circuit 33 that is a DC / AC converter, and a power factor of power. An active circuit 35 to be improved is mounted, and a radiation fin (not shown) is provided in close contact with the opposite side of the mounting surface of the inverter circuit 33. The smoothing capacitor 51 is disposed between the active circuit 35 and the inverter circuit 33 and is externally attached to the first substrate 27. The converter circuit 31 is formed by bridging a plurality of (four in this embodiment) rectifier elements 32 such as diodes, and an active circuit 35 via a magnet switch 30 for operating or stopping the refrigeration apparatus and a power factor reactor 34. It is connected to the. The active circuit 35 has a configuration in which the switching element 36 is disposed between the secondary side (+) line of the reactor 34 and the output side (−) line of the converter 31. The inverter circuit 33 is formed by bridge-connecting a plurality of switching elements 38, which are power semiconductors such as transistors. In this embodiment, the switching elements 38UP, 38UN, 38VP, 38VN, 38WP, and 38WN are three-phase bridge-connected. , U-phase, V-phase, and W-phase. Each switching element 38 is provided with a flywheel element 39 for regenerating back electromotive force flowing from the electric motor 11 during switching.
[0022]
The second board 28 includes a microcomputer 37 (indicated as a microcomputer in the figure) that is a control circuit, a driver circuit 41 that controls switching of the inverter circuit 33 based on a signal from the microcomputer 37, and a current of the motor 11. A power detection circuit 42 for detecting the power supply, a high voltage supplied from the power supply of the converter circuit 31 to about 5V, for example, and a power supply circuit 43 for supplying the microcomputer 37, the driver circuit 41, the current detection mechanism 42, and an active circuit 35 A power factor correction control mechanism 45 for driving the motor and a terminal block 47 of the electric motor 11 are provided.
[0023]
The third substrate 29 includes an inrush suppression resistor 49 provided in the magnet switch 30 for suppressing an inrush current to the electric motor 11, an interface connector 51 to which a signal from the control device 23 is input, and an input A photocoupler 53 is mounted which transmits the processed signal to the microcomputer 37 by an optical signal. The active circuit 35 provided on the first substrate is driven and controlled by the power factor correction control mechanism 45 disposed on the second substrate. However, the active circuit 35 is provided outside the first substrate. Therefore, the interface connector 55 is arranged on the second board.
[0024]
As shown in FIGS. 3 and 4, these substrates 27, 28, and 29 are stacked in a first, second, and third order from the bottom of the case 57 in a box-shaped case 57 that is open on the upper side. ing. A notch-shaped stepped portion 59 is formed on one side surface of the case 57, and a terminal block 47 is disposed at a portion of the second substrate 28 corresponding to the stepped portion 59. In addition, a converter circuit 31 and an inverter circuit 33 are disposed in a portion of the first board located directly below the terminal block 47.
[0025]
Further, as shown in the cross-sectional view of FIG. 5, the gel 61 is filled up to a substantially alternate long and short dash line A so as to cover the mounting surface of the switching element 38 of the first substrate 27, and the converter circuit 31, the inverter circuit 33, and the active circuit Elements such as a diode and an IGBT constituting the circuit 31 are protected. From the surface of the gel 61 to the substantially two-dot chain line B and the upper surface of the second substrate 20, a resin 63 is enclosed for protection and insulation, and the power module is assembled. In addition, on the back surface of the first substrate 27 mounted on the bottom surface of the case 57, heat radiation fins 65 that radiate heat from the converter circuit 31, the inverter circuit 33, and the active circuit 31 are thermally connected. Note that the first lead pin 67 for connecting the first substrate 27 and the second substrate 28 and the first substrate 27 and the third substrate 29 are connected within the side surface of the case 57. A second lead pin 69 is provided. The second substrate 28 and the third substrate 29 are connected by a third lead pin 71 provided on the upper surface of the second substrate 28, and the third substrate 29 is provided on the upper surface of the second substrate 28. It is supported by a substrate support spacer 73.
[0026]
The basic operation of the air conditioner configured as described above will be described. First, the operation of the air conditioner is started and the magnet switch 30 is turned on. The AC voltage from the single-phase AC power supply 25 is rectified by the converter circuit 31, and the power source power factor is increased via the magnet switch 30, the power factor reactor 34, the switching element 36 of the active circuit 35, and the first recovery element 37. The smoothing capacitor 51 is improved. A part of the direct current generated in this way is adjusted to about 5 V from the high voltage used in the inverter circuit 33 in the power supply circuit 43 and supplied to the microcomputer 37, the driver circuit 41, and the current detection mechanism 42, and the rest The direct current is supplied to the electric motor 11 via the inverter circuit 33. Note that the current detected by the current detection mechanism 42 is taken into the microcomputer 37 and monitored.
[0027]
The microcomputer 37 sends a direct current to the electric motor 11 without switching the inverter circuit 33 for a set time T, for example, 1 to 10 seconds from the start of activation, and sets the position of the rotor (not shown) of the electric motor 11. In addition to the initial position, the switching control of the inverter circuit 33 is started after a set time T has elapsed from the start of activation. Thereby, three-phase alternating current power is supplied to the electric motor 11, and the compressor 1 of the refrigerating cycle starts operation. The control device 23 sets the frequency required for the compressor 1 based on the temperature and pressure of each part of the refrigeration cycle, the operation mode and set temperature required from the outside, and the like. The set frequency of the compressor 1 is sent to the microcomputer 37 together with other operation information. The microcomputer 37 performs switching so that the frequency of the compressor 1 becomes the set frequency, and sets the AC frequency supplied to the motor 11. Adjust as appropriate.
[0028]
Further, between the microcomputer 37 and the control device 23, the temperature or pressure at each position of the refrigeration cycle, the opening degree of the expansion valve 5 of the indoor unit or the expansion valve of the outdoor unit (not shown), the rotation of the blowers 19 and 21. Number, state control signal of the four-way valve 15 for switching the operation mode of cooling / heating, inverter current, inverter frequency, abnormality of the inverter itself, normal state signal, etc. are transmitted and received through the photocoupler 51 with electrical isolation. Control is performed in cooperation with each other as appropriate. In particular, the operating frequency of the inverter is output via the interface connector 51 and the photocoupler 53, and the operating state of the refrigeration cycle is grasped, the cause is analyzed when it is stopped, and the failure analysis is performed.
[0029]
Next, the control operation of the inverter device 13 which is a characteristic part of the present embodiment will be described in detail with reference to FIGS. As described above, each time the motor 11 is started, the inverter device 13 causes the DC current to flow through the motor 11 for a set time to return the rotor position to the initial position, and then starts switching control. Specifically, as shown in FIG. 6, when the motor 11 is started, the microcomputer 37 determines the count number N stored in a storage unit (not shown) inside the microcomputer 37 (step S1). When N ≦ 6, 1 is added to the count number N (step S2) and the process proceeds to step S4. When N> 6, the count number N is reset to 1 (step S3) and the process proceeds to step S4.
[0030]
In step S4, the activation switching pattern corresponding to the current count number N is fetched from the storage unit (step S4). Then, the microcomputer 37 outputs a signal to the driver circuit 41 based on the acquired startup switching pattern (step S5), and allows a direct current to flow until the set time T elapses (step S6).
[0031]
It should be noted that this activation switching pattern is prepared as a pattern corresponding to the number of switching elements 38 (six patterns in the present embodiment). For example, in the first pattern, the switching element 38UP is turned on, 38UN is fixed off, and at least one of 38VN and 38WN is used. The Control switching. In the second pattern, the switching element 38UP is turned off, 38UN is fixed on, and 38V P 38W P At least one of The Control switching. In the third pattern, the switching element 38VP is turned on and 38VN is fixed off, and at least one of 38UN and 38WN The Control switching. In the fourth pattern, the switching element 38VP is turned off, 38VN is fixed on, and 38U P 38W P At least one of The Control switching. In the fifth pattern, the switching element 38WP is turned on and 38WN is fixed off, and at least one of 38UN and 38VN The Control switching. In the sixth pattern, the switching element 38WP is turned off, 38WN is fixed on, and 38U P 38V P At least one of The Control switching.
[0032]
Thus, by preparing six types of startup switching patterns and rotating the switching elements 38 to be energized, each switching element is energized only once every six startups of the motor 11, so that a certain specific It is possible to avoid the number of energizations of the switching element 38 from protruding and increase, and it is possible to suppress the temperature of the specific switching element 38 from excessively rising. Therefore, the temperature of each switching element 38 becomes average, and each is suppressed to a relatively low temperature. Therefore, it is sufficient that the fin has a capability of cooling the relatively low temperature to a temperature suitable for use. can do. In addition, since heat generation does not have to concentrate on a specific switching element 38, the order of repeating the first to sixth patterns can be arbitrarily set.
[0033]
Next, the control after the set time T of the microcomputer 37 will be described. When the set time T elapses in step S <b> 6 shown in FIG. 6, the microcomputer 37 starts from the inverter circuit 33 with the microcomputer 37 to rotate the motor 11 based on the frequency of the motor 11 input from the control device 23. Calculate the three-phase AC voltage command to be output. As shown in FIG. 8, the calculated three-phase AC voltage commands are of three types: a U-phase voltage command eoU, a V-phase voltage command eoV, and a W-phase voltage command eoW (step S7). As shown in FIG. 8, the phase voltage commands eoU, eoV, and eoW for each phase have a sine wave with the same amplitude and one cycle of 360 degrees, and the phase difference between them is 120 degrees.
[0034]
In steps S8 and 9, the values of the voltage commands eoU, eoV, and eoW for each phase are compared with the upper limit value eH and the lower limit value eL (steps S8 and 9). As a result of the comparison, when the voltage command ≧ the upper limit value eH, a signal for turning on the upper arm and turning off the lower arm is output to the driver circuit 41 (step S10), and when the voltage command <the lower limit value eL, A signal for turning off the upper arm and turning on the lower arm is output to the driver circuit 41 (step S11), and the process proceeds to step S12. In step S12, it is determined whether the operation of the compressor 1 is finished (step S12). If not finished, the process returns to step S8.
[0035]
Here, since the voltage command eoU, eoV, eoW of each phase is a sine wave, the upper limit value eH is set to (3/2) of the peak value eMax of the voltage command value. ^1/2 The lower limit eL is the voltage command value peak value eMax (3/2). ^1/2 By setting the double absolute value to a negative value, as shown in the lower part of FIG. 8, switching of each phase is stopped for each 1/3 period. Thus, by providing a period during which switching of the switching element 38 is not performed, heat generation and loss due to switching can be reduced, and fins that promote heat dissipation can be reduced. Further, since the phases of the voltage commands eoU, eoV, eoW of each phase are shifted from each other by 120 °, when the switching of one phase is stopped, the switching can be performed by the remaining two phases.
[0036]
This switching operation is performed when the lower limit value eL ≦ the voltage command <the upper limit value eH in steps S8 and S9. That is, the voltage command value is compared with a carrier wave eS having a predetermined waveform such as a triangular wave generated inside the microcomputer 37 (step S13). For example, in the case of the U phase, as shown in FIG. When eoU> carrier wave eS, a signal for turning on the switching element 38UP as the upper arm and turning off the switching element 38UN as the lower arm is output (step S10). When the voltage command eoU ≦ carrier eS, the switching element 38UP is turned on. A signal for turning off and switching element 38UN on is output (step S11), and the process proceeds to step S12. The comparison between the voltage command and the carrier wave eS is similarly performed in the V phase and the W phase.
[0037]
By the way, in the inverter device of this embodiment, the power supply GND (ground) is provided between switching elements 38UP, 38VP and 38WP called upper arms and switching elements 38UN, 38VN and 38WN called lower arms. In order to supply a voltage of, for example, 15 V necessary for driving each switching element 38 in the same manner, two types of power supplies having different voltages are required. In order to use only one type of power source, as shown in FIG. 9, capacitors 80 are provided on the drive power supply side of the upper arm, and the capacitors 80UN, 38VN and 38WN are turned on to charge each capacitor 80. It is conceivable to supply power.
[0038]
In such a configuration, in order to drive the switching element 38 of the upper arm, the capacitor 80 must be charged with a constant charge. However, since the upper arm circuit provided with the capacitor 80 is provided in parallel with the lower arm circuit, it cannot be charged when the lower arm is turned off. Therefore, in the present embodiment, when the first, third, and fifth patterns in which the lower arm is turned off in step S4, a minute time that allows the capacitor 80 to be charged, for example, several percent of one cycle of the carrier frequency. It can be set as the structure which performs control which turns on a lower arm only for time. Thereby, since the capacitor 80 can be charged, it is not necessary to provide two types of power sources.
[0039]
According to the present embodiment, the converter circuit 31, the inverter circuit 33, and the active circuit 35 are mounted on the same substrate, the microcomputer 37 that controls the switching element 38, and the current detection mechanism that detects the current of the electric motor 11. 42, because the second board 28 on which the motor terminal block 47 is mounted is compactly arranged close to the hierarchy, the wiring length of the portion where the possibility of noise generation is large can be shortened, so that noise generation Factors can be reduced.
[0040]
Further, according to the present embodiment, various temperature or pressure detection sensors of the refrigeration cycle, which are relatively weak signals having a large influence from the electromagnetic noise, for example, a large influence from the compressor 1 that requires a large current, are used. Since the third board 29 on which the interface connector 51 to which signals are input is mounted is disposed at the top and is transmitted to the microcomputer 37 by an optical signal, the refrigeration cycle is free from malfunction due to noise mixing. Can improve the reliability. Furthermore, since the power semiconductor surface of the first substrate 27 is filled with the gel 61 and the resin 63 is sealed from the surface of the gel 61 to the upper surface of the second substrate 28, the reliability of the power module ISPM itself can be improved.
[0041]
Furthermore, according to the present embodiment, the software of the microcomputer 37 according to the configuration of the refrigeration cycle, the refrigeration apparatus and the inverter apparatus used therefor, the capacity of the air conditioner, the model for shops, buildings, etc. When changing the hardware of the input / output interface, it is possible to easily cope with the problem by separating the uppermost third substrate 29. Even in this case, since the current values are arranged in descending order from the bottom surface of the case 57, the number of wirings can be reduced, and this can be handled relatively freely.
[0042]
In the present embodiment, the power source is the single-phase AC power source 25. However, instead of this, a three-phase AC power source 82 can be used as the power source as shown in FIG. In this case, a plurality of (six in the present embodiment) rectifier elements 32 such as diodes are formed by bridge connection, and a converter circuit 84 for converting the AC voltage from the three-phase AC power supply 82 to DC is provided. It can be set as the structure which does not provide the rate improvement mechanism 45. FIG.
[0043]
In the present embodiment, the microcomputer 37 required to vary the operating frequency of the electric motor 11 is required to have a high speed, but the capacity control of the refrigeration cycle, the mode switching of the air conditioning and the like are slow. The microcomputer 37 can share the control of the refrigeration cycle, for example, the expansion valve of the outdoor unit, the blower 21, and the four-way valve for switching the cooling / heating operation mode. In particular, if a drive circuit for the expansion valve of the outdoor unit is provided on the first substrate 27 and a signal for detecting the discharge gas temperature of the compressor 1 is input to the microcomputer 37 via the interface connector 51, the compressor 1 The discharge gas superheat can be optimally controlled by the microcomputer 37 with respect to the capacity and refrigerant flow rate, the control circuit for the entire refrigeration cycle can be simplified to reduce wiring and the like, and the entire apparatus can be made compact.
[0044]
Further, in the present embodiment, the case 57 may be made of metal by aluminum die casting or the like, but if it is made of resin, a complicated shape is possible at a low cost, so that the terminal block 47 is adapted to the step 59. The terminal block 47 does not protrude beyond the upper surface of the case 57. Therefore, a wasteful space can be eliminated even when the inverter device is mounted on, for example, an outdoor unit of an air conditioner, which is desirable from the viewpoint of suppressing electromagnetic noise.
[0045]
As described above, in the present embodiment, the substrate 27 having the power semiconductor such as the switching element 38 is the lowermost portion, the substrate 28 having the microcomputer 37 mounted thereon, and the substrate having the interface connector 51 mounted thereon. 29 is arranged hierarchically and compactly so that it is at the top, and signals of various temperature or pressure detection sensors of the refrigeration cycle are transmitted from the interface connector 51 to the microcomputer 37 by optical signals, so that noise generation occurs. The factors can be reduced and the reliability of the refrigeration cycle can be improved. Moreover, the amount of heat generated can be reduced by reducing the loss of the power semiconductor, the heat dissipation characteristics of the inverter device 13 can be improved, and the usable temperature range of the refrigeration device and the inverter device 13 used therefor can be widened and the life can be extended. In this embodiment, a three-phase induction motor is used as the electric motor. However, the present invention is not limited to this, and an arbitrary multi-phase induction motor can be used. Also, a permanent magnet synchronous motor in which a cage conductor and a permanent magnet are provided on the iron core of the rotor can be used.
[0046]
【The invention's effect】
As described above, according to the present invention, the temperature rise of the power semiconductor can be suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an air conditioner using a refrigeration apparatus to which the present invention is applied.
FIG. 2 is a circuit diagram showing a schematic configuration of an embodiment of an inverter device to which the present invention is applied.
FIG. 3 is a perspective view illustrating an assembly configuration of an embodiment of an inverter device to which the present invention is applied.
FIG. 4 is a perspective view of an embodiment of an inverter device to which the present invention is applied.
FIG. 5 is a sectional view showing a schematic configuration of an embodiment of an inverter device to which the present invention is applied.
FIG. 6 is a flowchart showing control of a microcomputer of an embodiment of an inverter device to which the present invention is applied.
FIG. 7 is a graph for explaining PWM control, showing carrier wave eS, voltage command eoU, and control signals to switching elements 38UP and 38UN in an embodiment of an inverter device to which the present invention is applied.
FIG. 8 shows control signals to voltage commands eoU, eoV, eoW and switching elements 38UP, 38UN, 38VP, 38VN, 38WP, 38WN of each phase in an embodiment of the inverter device to which the present invention is applied; It is a graph explaining two-phase PWM control.
FIG. 9 is a circuit diagram illustrating a detailed configuration of a driver circuit 41 and an inverter circuit 33 of an embodiment of an inverter device to which the present invention is applied.
FIG. 10 is a circuit diagram showing a modification of the embodiment of the inverter device to which the present invention is applied.
[Explanation of symbols]
1 Compressor
11 Electric motor
13 Inverter device
23 Control device
25 Single-phase AC power supply
27 First substrate
28 Second substrate
29 Third substrate
31 Converter circuit
33 Inverter circuit
35 Active circuit
37 Microcomputer
41 Driver circuit
43 Power supply circuit

Claims (5)

A plurality of bridge-connected power semiconductors forming an inverter circuit and a control circuit for controlling the on / off operation of each power semiconductor are converted into DC power supplied to the inverter circuit and supplied to the motor An inverter device that performs
Immediately before driving the electric motor, the control circuit includes a power semiconductor of one of upper and lower arms of one of the phases of the plurality of power semiconductors connected to the bridge and an upper and lower arm of a phase different from the phase for a set time is fixed to the switching pattern for the power semiconductor-on operation, performs control to adjust the rotor of the motor to the initial position by applying a DC current to said electric motor, said to be fixed to the on-operation every time performing the control An inverter device characterized by rotating a switching pattern of a power semiconductor . The inverter device according to claim 1,
When the electric motor is driven, the control circuit fixes one power semiconductor of one of the plurality of bridge-connected power semiconductors to an on operation and the other power semiconductor to an off operation, and An inverter device that controls an on / off operation of a power semiconductor and sequentially switches a phase to which a power semiconductor to which the on / off operation is to be fixed belongs. In the inverter device according to claim 1 or 2,
A first circuit board on which a converter circuit for supplying AC power from an AC power source to DC power and supplying the inverter circuit and a power semiconductor constituting the inverter circuit are mounted, and radiation fins are attached to the opposite surface of the mounting surface; ,
A second board on which the control circuit, a current detection mechanism for detecting a current of the motor and inputting the current to the control circuit, and a terminal block of the motor are mounted;
An interface connector to which signals of various temperatures or pressures of the refrigeration cycle are input, and a photocoupler for transmitting a signal input through the interface connector to the control circuit by an optical signal are mounted. A substrate of
The first substrate, the second substrate, and the third substrate stacked in order from the bottom are stored, and the gel is filled up to the mounting surface of the power semiconductor of the first substrate, and the second substrate from the gel surface And a box-shaped case in which resin is sealed up to the upper surface of
The control circuit monitors the state of the electric motor with a current input from the current detection mechanism, and based on various temperatures or pressures of the refrigeration cycle input through the interface connector and the photocoupler. An inverter device that performs variable speed control of an electric motor. In the inverter device according to claim 3,
An inverter device, wherein an active circuit for improving a power factor is mounted on the first substrate, and a mechanism for controlling the active circuit is mounted on the second substrate.   A compressor driven by the electric motor, a condenser for cooling and condensing the refrigerant gas compressed by the compressor, a pressure reducing valve for reducing the pressure of the liquid refrigerant discharged from the condenser, and the pressure reducing valve 5. A refrigeration cycle formed by an evaporator that evaporates the liquid refrigerant to be led to return to the compressor as a refrigerant gas, and the inverter device according to claim 1 that controls the electric motor. Refrigeration equipment.

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