Circuit body and air conditioner

Abstract

The invention provides a circuit body and an air conditioner, which can improve reliability. A circuit body (100) is provided with: a noise filter circuit (10) connected to a three-phase four-wire AC power supply (E1); an inverter circuit (20) connected to the output side of the noise filter circuit (10) via three-phase power lines (8R, 8S, 8T) different from the neutral line (8N); and a power supply circuit (30) to which a single-phase AC voltage is applied via one of the three-phase power lines (8R, 8S, 8T) and the neutral line (8N), the noise filter circuit (10) having at least three first variable resistors (1R, 1S, 1T), one end of each of the first variable resistors (1R, 1S, 1T) being individually connected to the three-phase power lines (8R, 8S, 8T) and the other end being not connected to the neutral line (8N).

Description

Technical Field

[0001] The present disclosure relates to circuit bodies and the like. Background Art

[0002] Regarding a circuit body that supplies power from a three-phase four-wire AC power supply, for example, the technology described in Patent Document 1 is known. That is, Patent Document 1 describes a power conversion device that includes "a power conversion module that converts output power of three phases other than the N phase from a three-phase four-wire power supply consisting of an R phase, an S phase, a T phase, and an N phase", and includes "an N-phase missing phase detection unit that detects the missing phase of the N phase using a drive control power supply as a power supply".

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-169334 Summary of the invention

[0004] For example, in order to protect the circuit from transient abnormal voltages such as interference surges and lightning surges, surge protection elements such as variable resistors are sometimes provided in three-phase power lines. When the technology of Patent Document 1 is applied to such a structure, an overvoltage (line voltage) is applied to the surge protection element when a phase loss of the N phase (neutral line) occurs, so the surge protection element may be damaged.

[0005] Therefore, an object of the present disclosure is to provide a circuit body and the like having high reliability.

[0006] In order to solve the above-mentioned problems, the circuit body of the present invention includes: a noise filter circuit, which is connected to a three-phase four-wire AC power supply; an inverter circuit, which is connected to the output side of the noise filter circuit via a three-phase power line different from a neutral line; and a power supply circuit, to which a single-phase AC voltage is applied via one of the three-phase power lines and the neutral line, and the noise filter circuit has at least three first surge protection elements, one end of each of the first surge protection elements is individually connected to the three-phase power line correspondingly, and the other end is not connected to the neutral line, and the other end is not grounded.

[0007] According to the present disclosure, a circuit body and the like having high reliability can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a circuit diagram including the circuit body of the first embodiment.

[0009] Figure 2 : is a circuit diagram showing the structure of the circuit body according to the first embodiment.

[0010] Figure 3 : is a circuit diagram showing the structure of a circuit body according to the second embodiment.

[0011] Figure 4 It is a configuration diagram of an air conditioner according to a third embodiment.

[0012] Figure 5 This is a perspective view of a state where side panels and a top panel are removed from a housing of an outdoor unit of an air conditioner according to a third embodiment.

[0013] Figure 6 : is a circuit diagram showing the structure of a circuit body according to a first modification.

[0014] Figure 7 : is a circuit diagram showing the structure of a circuit body according to a second modification.

[0015] Figure 8 : is a circuit diagram showing the structure of a circuit body of a comparative example. DETAILED DESCRIPTION

[0016] <<First Implementation Method>>

[0017] Figure 1 1 is a circuit diagram including the circuit body 100 according to the first embodiment.

[0018] Figure 1 The circuit body 100 shown in the figure has a three-phase four-wire AC power source E1 (see Figure 2 ) to perform predetermined power conversion on the AC power supplied by the power transformer, and also has the function of protecting circuit components from interference surges and lightning surges. Figure 1 As shown, the circuit body 100 includes a terminal block B1, a noise filter substrate B2, an inverter substrate B3, and a control substrate B4. The terminal block B1 is a device for connecting the R-phase, S-phase, and T-phase power lines and the N-phase neutral line of the three-phase four-wire system.

[0019] In addition, "three-phase four-wire system" refers to a method of distributing three-phase AC power using R-phase, S-phase, and T-phase power lines and an N-phase neutral line. The N-phase neutral line is drawn from the neutral point of the secondary side of a star-connected transformer (not shown), for example. By using such a three-phase four-wire power distribution method, two power sources, three-phase AC power and single-phase AC power, can be obtained. Therefore, the three-phase four-wire power distribution method is particularly effective when three-phase loads and single-phase loads are mixed. Figure 1 As shown, the power lines of the R phase, S phase, and T phase and the neutral line of the N phase are connected to the noise filter substrate B2 via the terminal block B1.

[0020] The noise filter substrate B2 is a substrate for suppressing interference surges and lightning surges. A noise filter circuit 10 (see FIG. 1 ) described later is mounted on the noise filter substrate B2. Figure 2). The noise filter substrate B2 is connected to the inverter circuit 20 via the power lines of the R phase, S phase, and T phase. In addition, predetermined single-phase AC power is supplied from the noise filter substrate B2 to the power circuit 30, the instantaneous power failure detection circuit 40, and the 200V system load 50 via the power line of the R phase and the neutral line of the N phase.

[0021] The inverter circuit 20 is a power converter that sequentially rectifies and smoothes three-phase AC power, converts DC power into predetermined AC power, and outputs the AC power to the motor M1. The motor M1 is used as a drive source for a compressor of an air conditioner, for example.

[0022] The power supply circuit 30 is a microcomputer 25 (see Figure 2 )、Control circuit 26 (refer to Figure 2 ) and the microcomputer 44 of the momentary power failure detection circuit 40 (refer to Figure 2 ) respectively correspond to the predetermined voltage circuit. Figure 1 As shown, the inverter circuit 20 and the power supply circuit 30 are mounted on the inverter board B3.

[0023] The instantaneous power failure detection circuit 40 is a circuit for detecting an instantaneous voltage drop caused by a lightning strike or the like on a power transmission line (not shown). Figure 1 As shown, the momentary power failure detection circuit 40 is mounted on the control substrate B4. In addition, a predetermined microcomputer or control circuit may be mounted on the control substrate B4.

[0024] Figure 1 The electric box X1 shown is a box body for accommodating the noise filter substrate B2, the inverter substrate B3, and the control substrate B4 in addition to the terminal block B1. The 200V system load 50 is a load such as an expansion valve or a four-way valve of an air conditioner. A single-phase AC voltage is supplied to the 200V system load 50 via the noise filter substrate B2. In addition, "200V" is an example, and the rated voltage of the load may also be a value different from 200V.

[0025] Figure 2 is a circuit diagram showing the structure of the circuit body 100 .

[0026] As described above, the three-phase four-wire AC power source E1 is used to distribute power to the circuit body 100. Specifically, the R-phase power line 8 R 、S-phase power line 8 S , T-phase power line 8 T And the neutral line of N phase 8 N The noise filter circuit 10 is connected via the terminal block B1. The noise filter circuit 10 is a circuit for suppressing interference surges and lightning surges, and is connected to a three-phase four-wire AC power source E1 via the terminal block B1.

[0027] like Figure 2 As shown, the noise filter circuit 10 includes a first variable resistor 1 R , 1 S , 1 T (First surge protection element), discharge resistor 2 R , 2 S , 2 T , the first X capacitor 3 R , 3 S , 3 T (X capacitor), Y capacitor 4 R , 4 S , 4 T and the second X capacitor 5 R , 5 S , 5 T Furthermore, the noise filter circuit 10 includes a second variable resistor 6N (a second surge protection element) and a surge absorber 7 in addition to the above-mentioned configuration.

[0028] Power line 8 with R phase R Connect the first variable resistor 1 R The first variable resistor 1 is a resistor element having a nonlinear voltage-current characteristic. R The first variable resistor 1R has the following characteristics: when the voltage applied to the first variable resistor 1R is greater than a predetermined value, the first variable resistor 1 R For example, when a high voltage is applied to the first variable resistor 1 instantaneously with an interference surge, R When the first variable resistor 1 R The resistance value of the first variable resistor 1 decreases sharply, thereby R Thus, the inverter circuit 20 on the subsequent stage of the noise filter circuit 10 is protected from the influence of interference surges and the like. S Connect the first variable resistor 1 S , and the power line 8 of phase T T Connect the first variable resistor 1 T The same is true.

[0029] like Figure 2 As shown, each first variable resistor 1 R , 1 S , 1 T One end of the (first surge protection element) is connected to the three-phase power line 8 R , 8 S , 8 T For example, the first variable resistor 1 of the R phase R One end (one of a pair of leads) is connected to the R-phase power line 8 via wiring.R Similarly, the first variable resistor 1 of the S phase S One end of the S phase power line 8 S Connect, in addition, the first variable resistor 1 of the T phase T One end of the power line 8 of phase T T connect.

[0030] In addition, each first variable resistor 1 R , 1 S , 1 T The other ends of the first surge protection element are connected to each other. That is, the first variable resistor 1 of the R phase R The other end (the other of a pair of leads), the first variable resistor 1 of the S phase S The other end and the first variable resistor 1 of the T phase T The other ends are connected to each other.

[0031] like Figure 2 As shown, the neutral line of the N phase 8 N Not with the first variable resistor 1 R , 1 S , 1 T In other words, each first variable resistor 1 R , 1 S , 1 T The other end of the (first surge protection element) is not connected to the neutral line 8 N Here, “not connected to the neutral line 8N” means that the first variable resistor 1 R , 1 S , 1 T The other end is not wired to the neutral line 8 N The details will be described later. By configuring the first variable resistor 1 R , 1 S , 1 T Not connected to the neutral line 8N, it can prevent the first variable resistor 1 from being disconnected when the N phase is missing. R , 1 S , 1 T As a result, the first variable resistor 1 can be prevented from being disconnected when the N phase is missing. R , 1 S , 1 T damage or bad condition.

[0032] Discharge resistor 2 R is used to consume the first X capacitor 3 R The residual charge of the resistance element is connected to the R phase power line 8 via a wiring. R Similarly, the discharge resistor 2 S One end of the S phase power line 8S Connect, in addition, the discharge resistor 2 of the T phase T One end of the power line 8 of phase T T That is, the discharge resistor 2 R , 2 S , 2 T One end of the three-phase power line 8 R , 8 S , 8 T In addition, the discharge resistor 2 R , 2 S , 2 T The other end of each is connected to the first variable resistor 1 R , 1 S , 1 T The other ends are connected to each other.

[0033] First X capacitor 3 R This capacitor is mainly used to suppress normal mode noise. One end of the capacitor is connected to the R-phase power line 8 via wiring. R Similarly, the first X capacitor 3 of the S phase S One end of the S phase power line 8 S Connect, additionally, the first X capacitor of T phase 3 T One end of the power line 8 of phase T T That is, the first X capacitor 3 R , 3 S , 3 T One end of the three-phase power line 8 R , 8 S , 8 T Connect accordingly.

[0034] In addition, the first X capacitor 3 R , 3 S , 3 T The other end of each is connected to the first variable resistor 1 R , 1 S , 1 T and discharge resistor 2 R , 2 S , 2 T In other words, the first variable resistor 1 R , 1 S , 1 T (First surge protection element), discharge resistor 2 R , 2 S , 2 T and the first X capacitor 3 R , 3 S , 3 T The other ends of the (X capacitors) are connected to each other.

[0035] In addition, the first variable resistor 1 R , 1 S , 1 T 、Discharge resistor 2 R , 2 S , 2 T , the first X capacitor 3 R , 3 S , 3 T The other ends of the two terminals are connected to each other, but the connection point does not need to be grounded. This is because, if the connection point is grounded, it is easy to connect the two terminals to the discharge resistor 2. R , 2 S , 2 T The leakage current flows, and as a result, the possibility of a leakage breaker (not shown) being actuated in a normal state increases.

[0036] Y capacitor 4 R This capacitor is mainly used to suppress common mode noise. One end of the capacitor is connected to the R-phase power line 8 via wiring. R Similarly, the Y capacitor 4 of the S phase S One end of the S phase power line 8 S Connect, in addition, the Y capacitor 4 of the T phase T One end of the power line 8 of phase T T That is, the Y capacitor 4 R , 4 S , 4 T One end of the three-phase power line 8 R , 8 S , 8 T In addition, the Y capacitor 4 R , 4 S , 4 T The other end of each is connected via the neutral line 8 N (More specifically, the third neutral line 83 N ) ground.

[0037] Second X capacitor 5 R This capacitor is mainly used to suppress normal mode noise. One end of the capacitor is connected to the R-phase power line 8 via wiring. R Similarly, the second X capacitor 5 of the S phase S One end of the capacitor 8S is connected to the S-phase power line 8S, and the second X capacitor 5 of the T-phase T One end of the power line 8 of phase T T In addition, the second X capacitor 5 R , 5 S , 5 T The other ends of each are connected to each other. R , 3S , 3 T 、Y capacitor 4 R , 4 S , 4 T , the second X capacitor 5 R , 5 S , 5 T , which can improve the attenuation characteristics when attenuating noise.

[0038] Figure 2 The neutral line shown is 8 N Having a first neutral line 81 N , second neutral line 82 N And the third neutral line 83 N . The first neutral line 81 N One end is connected to the terminal block B1, and the other end is connected to the second variable resistor 6 N and the surge absorber 7 and is grounded. N One end of the first neutral line 81 N (Terminal block B1 and second variable resistor 6 N The other end is branched into three, connected to the power supply circuit 30, the instantaneous power failure detection circuit 40, and the 200V system load 50. The third neutral line 83 N One end of the Y capacitor 4 R , 4 S , 4 T The other end is connected to the connection part of the first neutral line 81 N (Ground side of surge absorber 7) connection.

[0039] The second variable resistor 6 N The second surge protection element is an element for suppressing instantaneous voltage fluctuation (surge) and is provided on the first neutral line 81. N As described above, since the noise filter circuit 10 is mounted on the noise filter substrate B2 (refer to Figure 1 ), so the second variable resistor 6 N The second surge protection element is also mounted on the noise filter substrate B2 (see Figure 1 )superior.

[0040] The surge absorber 7 is a device that absorbs surges (reduces resistance value to allow current to flow) when a disturbance surge or lightning surge is generated and a high voltage is applied, and is provided on the first neutral line 81. N .exist Figure 2 In the example, one end of the surge absorber 7 is connected to the second variable resistor 6 N connection and the other end to ground.

[0041] The inverter circuit 20 is a circuit that receives power from the noise filter circuit 10 via the power line 8. R , 8 S , 8 T The inverter circuit 20 converts the applied three-phase AC voltage into a DC voltage, further converts the DC voltage into a predetermined three-phase AC voltage, and applies it to the three-phase winding of the motor M1. R , 8 S , 8 T Connected to the output side of the noise filter circuit 10 .

[0042] like Figure 2 As shown, the inverter circuit 20 includes a rectifier circuit 21, a reactor 22, a smoothing capacitor 23, an inverter 24, a microcomputer 25, and a control circuit 26. The rectifier circuit 21 rectifies the three-phase AC voltage of the R phase, S phase, and T phase applied via the noise filter circuit 10, and converts it into a pulsating current-shaped DC voltage. As such a rectifier circuit 21, for example, a diode bridge circuit is used. The output side of the rectifier circuit 21 is connected to the inverter 24 via the positive side wiring 27a, and is connected to the inverter 24 via the negative side wiring 27b.

[0043] The reactor 22 has a function of suppressing harmonics and is provided on the positive side wiring 27a. The smoothing capacitor 23 smoothes the pulsating current-like DC voltage applied from the rectifier circuit 21. The positive electrode of the smoothing capacitor 23 is connected to the positive side wiring 27a (between the reactor 22 and the inverter 24), and the negative electrode is connected to the wiring 27b.

[0044] The inverter 24 is a circuit that converts the DC voltage smoothed by the smoothing capacitor 23 into a predetermined three-phase AC voltage. The inverter 24 is configured such that a first branch, a second branch, and a third branch including a pair of switching elements S1 and S2 are connected in parallel to each other. The positive side of the first branch, the second branch, and the third branch are connected to the wiring 27a, and the negative side is connected to the wiring 27b. In addition, the connection point of the pair of switching elements S1 and S2 of each branch is connected to the three-phase winding of the motor M1 via wiring.

[0045] The microcomputer 25 calculates the voltage command value and the current command value of the motor M1 based on a predetermined program. The control circuit 26 performs PWM control (Pulse Width Modulation) based on the command signal from the microcomputer 25, and outputs a predetermined PWM signal to the inverter 24. Thus, the on / off of each switching element S1, S2 is switched in a predetermined manner.

[0046] As mentioned above, Figure 2The power supply circuit 30 shown is a circuit for generating a predetermined DC voltage (DC voltages Vdd1, Vdd2, Vdd3). R , 8 S , 8 T One of the Figure 2 In the example, the power line 81 of the R phase R ) and neutral line 8 N A single-phase AC voltage is applied to the power supply circuit 30. R One end of the power line 8 R The other end is branched into three and connected to the input side of the power supply circuit 30 , the instantaneous power failure detection circuit 40 and the 200V system load 50 .

[0047] like Figure 2 As shown, the power supply circuit 30 includes a third variable resistor 31, a filter circuit 32, an NTC (Negative Temperature Coefficient) thermistor 33, a rectifier circuit 34, a smoothing capacitor 35, and a DC / DC converter 36. The third variable resistor 31 has a function of suppressing interference surges and lightning surges on the input side of the power supply circuit 30. The filter circuit 32 is used to suppress harmonics associated with the operation of the power supply circuit 30.

[0048] The NTC thermistor 33 is a component whose resistance value changes with temperature, and functions as a surge current prevention resistor. Figure 2 As shown, the NTC thermistor 33 is provided on one side (at the Figure 2 The rectifier circuit 34 converts the single-phase AC voltage applied via the filter circuit 32 into a pulsating current-like DC voltage.

[0049] The smoothing capacitor 35 is a capacitor that smoothes the pulsating current-like DC voltage applied from the rectifier circuit 34. The DC / DC converter 36 is a circuit that converts the DC voltage smoothed by the smoothing capacitor 35 into a DC voltage of a predetermined magnitude. A predetermined DC voltage Vdd1 of the DC voltage converted by the DC / DC converter 36 is applied to the microcomputer 25 of the inverter circuit 20, and another DC voltage Vdd2 is applied to the microcomputer 44 of the instantaneous power failure detection circuit 40. In addition, the DC voltage Vdd3 is applied to the control circuit 26 of the inverter circuit 20.

[0050] As described above, the instantaneous power failure detection circuit 40 is a circuit for detecting an instantaneous voltage drop associated with a lightning strike or the like on a power transmission line (not shown). Figure 2As shown, the instantaneous power failure detection circuit 40 includes a filter circuit 41, voltage-dividing resistors 42a and 42b, an insulation circuit 43, and a microcomputer 44. The filter circuit 41 is a circuit for suppressing harmonics.

[0051] The voltage dividing resistors 42a and 42b are resistor elements for dividing the voltage on the output side of the filter circuit 41 in a predetermined manner. Figure 2 In the example, a voltage dividing resistor 42a is provided on one of a pair of wirings 45a and 45b on the output side of the filter circuit 41. One end of the other voltage dividing resistor 42b is connected to the wiring 45a, and the other end is connected to the wiring 45b.

[0052] The insulating circuit 43 is electrically insulated from the microcomputer 44, and outputs a predetermined signal having a value proportional to the voltage across the voltage-dividing resistor 42b to the microcomputer 44. As such an insulating circuit 43, for example, a photocoupler is used. When the microcomputer 44 determines that a momentary power failure has occurred based on the signal input from the insulating circuit 43, the microcomputer 44 outputs a predetermined signal indicating the momentary power failure to the microcomputer 25 of the inverter circuit 20. Thus, the inverter circuit 20 is stopped when a momentary power failure occurs. Next, in the structure of the comparative example (refer to Figure 8 ) are described, and then the function and effect of the circuit body 100 of the first embodiment are described.

[0053] Figure 8 : is a circuit diagram showing the structure of a circuit body 100G of a comparative example.

[0054] in addition, Figure 8 Comparative Example and the First Embodiment (refer to Figure 2 ) is that the neutral line of the N phase is 8 N (Specifically, the first neutral line 81 N ) and the first variable resistor 1 R , 1 S , 1 T In addition, Figure 8 Comparative Example and the First Embodiment (refer to Figure 2 ) is that the first X capacitor 3 R , 3 S , 3 T and Y capacitor 4 R , 4 S , 4 T The other end of each is connected to the second variable resistor 6 N The surge absorber 7 is connected. The rest is the same as that of the first embodiment, and thus the description thereof is omitted.

[0055] exist Figure 8In the structure shown in the figure, in normal condition when there is no N-phase loss, the first variable resistor 1 R , 1 S , 1 T Predetermined phase voltages are applied respectively. That is, the first variable resistor 1 R , 1 S , 1 T A phase voltage of 1 / √3 of the line voltage of the AC power source E1 is applied to each of them.

[0056] However, when installing the circuit body 100, the operator forgets to connect the neutral line 8 N connection, or generate a neutral line 8 N The connection of the neutral line is poor or the neutral line is 8 N When the line is broken, the N phase may be lost. N The state in which the AC power source E1 is not electrically connected.

[0057] exist Figure 8 In the structure of the comparative example, when the N phase is missing, the first variable resistor 1 R , 1 S , 1 T That is, a line voltage of √3 times the phase voltage normally applied is applied to the first variable resistor 1. R , 1 S , 1 T The line voltage is higher than the first variable resistor 1. R , 1 S , 1 T In the case of high withstand voltage, the first variable resistor 1 R , 1 S , 1 T There is a possibility of damage due to overvoltage.

[0058] In contrast, in the first embodiment (see Figure 2 ), the neutral line of the N phase 8 N Not with the first variable resistor 1 R , 1 S , 1 T Connect to the R-phase, S-phase, and T-phase power lines 8 R , 8 S , 8 T As a result, even if the N phase is lost, since there is no line voltage circuit, it is possible to prevent overvoltage from being applied to the first variable resistors 1R, 1S, and 1T. That is, in a configuration that receives power from a three-phase four-wire AC power source E1, even if the N phase is lost, it is possible to prevent the first variable resistors 1R, 1S, and 1T from being lost. R , 1 S , 1T The reliability is improved compared with the comparative example.

[0059] In addition, since the first variable resistor 1 R , 1 S , 1 T The other ends of the first variable resistor 1 are connected to each other, so whether there is a phase loss or not, R , 1 S , 1 T A phase voltage of 1 / √3 of the line voltage is applied. As a result, the first variable resistor 1 R , 1 S , 1 T Since a variable resistor with a low withstand voltage can be used, the manufacturing cost of the circuit body 100 can be reduced.

[0060] In addition, since the second variable resistor 6 is provided on the first neutral line 81N N , the surge absorber 7, thereby suppressing the first neutral line 81 N The interference surge between the second variable resistor 6 and the ground line (grounding point) is N , the surge absorber 7 is mounted on the noise filter substrate B2 (refer to Figure 1 ), so the first neutral line 81 can be appropriately suppressed in the noise filter substrate B2 N Interference surge between the ground wire (grounding point).

[0061] Second Implementation Method

[0062] The second embodiment is different from the first embodiment in that the first variable resistor 1 R , 1 S , 1 T (Refer to Figure 3 ) are not connected to each other, but to the power line 8 R , 8 S , 8 T (Refer to Figure 3 ) are connected one to one. In addition, the rest is the same as the first embodiment. Therefore, the parts different from the first embodiment are described, and the description of the repeated parts is omitted.

[0063] Figure 3 1 is a circuit diagram showing the structure of a circuit body 100A according to the second embodiment.

[0064] like Figure 3 As shown, the noise filter circuit 10A of the circuit body 100A includes a first variable resistor 1 R , 1 S , 1 T (first surge protection element) and other various elements. Each first variable resistor 1R , 1 S , 1 T One end of the three-phase power line 8 R , 8 S , 8 T In addition, the first variable resistor 1 R , 1 S , 1 T The other end is not connected to the neutral line 8 N These aspects are similar to those of the first embodiment (see Figure 2 )same.

[0065] Furthermore, each first variable resistor 1 R , 1 S , 1 T The other ends are not connected to each other, but are connected to the first variable resistor 1 R , 1 S , 1 T Specifically, the first variable resistor 1 R One end of the R phase power line 8 R Connect the other end to the S phase power line 8 S Another first variable resistor 1 S One end of the S phase power line 8 S Connect the other end to the T-phase power line 8 T In addition, the remaining first variable resistor 1 T One end of the power line 8 of phase T T Connect the other end to the R phase power line 8 R Thus, each first variable resistor 1 R , 1 S , 1 T The other end of the first surge protection element is connected to the three-phase power line 8 R , 8 S , 8 T Any one of them is connected so that the first variable resistor 1 R , 1 S , 1 T The line voltage of the AC power source E1 is applied.

[0066] Discharge resistor 2 R , 2 S , 2 T One end of each capacitor is connected to the three-phase power lines 8R, 8S, and 8T. R , 3 S , 3 T One end of the (X capacitor) is connected to the three-phase power line 8 R , 8S , 8 T In addition, the discharge resistor 2 R , 2 S , 2 T and the first X capacitor 3 R , 3 S , 3 T The other ends of each are connected to each other.

[0067] For example, in a normal state when there is no N-phase loss, the first variable resistor 1 R , 1 S , 1 T The line voltage of the AC power source E1 is applied to each of them. In addition, when a phase loss of the N phase occurs, the first variable resistor 1 R , 1 S , 1 T The line voltage of the AC power source E1 is applied to the first variable resistor 1 in normal state and when the N phase is missing. R , 1 S , 1 T The voltage of the first variable resistor 1 hardly changes. R , 1 S , 1 T By using a variable resistor with a higher withstand voltage than the line voltage of the AC power source E1, the first variable resistor 1 can be prevented from being damaged even when the N phase is missing. R , 1 S , 1 T damage or defect.

[0068] In addition, even if the discharge resistor 2 R , 2 S , 2 T or the first X capacitor 3 R , 3 S , 3 T When the first variable resistor 1 is short-circuited and becomes a short-circuit fault, the first variable resistor 1 is also R , 1 S , 1 T The line voltage of the AC power source E1 is applied respectively. Therefore, the first variable resistor 1 can be prevented from R , 1 S , 1 T damage or defect, improving reliability.

[0069] 《Third Implementation Mode》

[0070] In the third embodiment, a circuit body 100 (see Figure 2 ) of the air conditioner 200 (refer to Figure 4 ) is described. In addition, the circuit body 100 (refer to Figure 2 ) is the same as that of the first embodiment, so the description is omitted.

[0071] Figure 4 It is a configuration diagram of an air conditioner 200 according to the third embodiment.

[0072] in addition, Figure 4 The solid arrows indicate the flow of the refrigerant in the heating cycle.

[0073] in addition, Figure 4 The dashed arrows indicate the flow of the refrigerant in the refrigeration cycle.

[0074] The air conditioner 200 is a device that performs air conditioning such as cooling operation and heating operation, and includes an outdoor unit U1 and an indoor unit U2. The outdoor unit U1 and the indoor unit U2 are connected via a refrigerant pipe.

[0075] The air conditioner 200 includes a compressor 61, an outdoor heat exchanger 62, an outdoor fan 63, an expansion valve 64, and a four-way valve 67 as components provided in the outdoor unit U1. In addition, the air conditioner 200 includes an indoor heat exchanger 65 and an indoor fan 66 as components provided in the indoor unit U2.

[0076] The compressor 61 is a device that compresses low-temperature and low-pressure gas refrigerant and discharges it as high-temperature and high-pressure gas refrigerant, and has a compressor motor 61a as a driving source. Figure 2 ) of the load side motor M1 (refer to Figure 2 ) may be the compressor motor 61a, or the outdoor fan motor 63a described later. Figure 4 Although not shown in the figure, the liquid storage device 68 (see Figure 5 ) is arranged on the suction side of the compressor 61.

[0077] The outdoor heat exchanger 62 is a heat exchanger in which the flow passes through the heat transfer tube 62b (refer to Figure 5 ) and the outside air sent in from the outdoor fan 63. The outdoor fan 63 is a fan that sends the outside air to the outdoor heat exchanger 62. The outdoor fan 63 has an outdoor fan motor 63a as a driving source and is arranged near the outdoor heat exchanger 62.

[0078] The expansion valve 64 is a valve that decompresses the refrigerant condensed in the "condenser" (one of the outdoor heat exchanger 62 and the indoor heat exchanger 65). The refrigerant decompressed by the expansion valve 64 is guided to the "evaporator" (the other of the outdoor heat exchanger 62 and the indoor heat exchanger 65).

[0079] The indoor heat exchanger 65 is a heat exchanger that performs heat exchange between the refrigerant flowing through the heat transfer tube (not shown) and the indoor air (air in the air-conditioned room) sent in from the indoor fan 66. The indoor fan 66 is a fan that sends indoor air to the indoor heat exchanger 65 and is installed near the indoor heat exchanger 65.

[0080] The four-way valve 67 is a valve that switches the flow path of the refrigerant according to the operation mode of the air conditioner 200. For example, in the refrigeration cycle (see Figure 4 In the refrigerant circuit Q1, the refrigerant circulates sequentially through the compressor 61, the outdoor heat exchanger 62 (condenser), the expansion valve 64, and the indoor heat exchanger 65 (evaporator). Figure 4 In the refrigerant circuit Q1, the refrigerant circulates sequentially through the compressor 61, the indoor heat exchanger 65 (condenser), the expansion valve 64, and the outdoor heat exchanger 62 (evaporator).

[0081] In addition, the air conditioner 200 receives a three-phase four-wire AC power source E1 (see Figure 2 ) When receiving power supply, the power supply to the outdoor unit U1 can be performed via the indoor unit U2. In addition, it can also be performed without passing through the indoor unit U2. It can be arbitrary.

[0082] Figure 5 This is a perspective view of a state where the side panels and the top panel are removed from the housing 69 of the outdoor unit U1.

[0083] like Figure 5 As shown, in addition to the compressor 61 , the accumulator 68 , the outdoor heat exchanger 62 , and the outdoor fan 63 , an electric box X1 is provided in the housing 69 of the outdoor unit U1 .

[0084] In addition, an outdoor heat exchanger 62 having an L-shape in a plan view is provided on a bottom plate 69a of the frame 69. The outdoor heat exchanger 62 includes a plurality of fans 62a arranged at predetermined intervals and a plurality of heat transfer pipes 62b penetrating the fans 62a. Heat exchange is performed between the external air sent in by the outdoor fan 63 and the refrigerant flowing in the heat transfer pipes 62b. Figure 5 The electric box X1 shown is a circuit body 100 (see Figure 2 ) is electrically grounded. Thus, the circuit body 100 (refer to Figure 2 ) is set in the structure of outdoor unit U1.

[0085] According to the third embodiment, the outdoor unit U1 of the air conditioner 200 includes a circuit body 100 (see Figure 2 ), even if the N phase is missing in the structure receiving the power supply of the three-phase four-wire system, the first variable resistor 1 can be prevented fromR , 1 S , 1 T (Refer to Figure 2 ) is damaged or defective. Therefore, the reliability of the air conditioner 200 is improved compared with the past.

[0086] 《Variation Example》

[0087] As described above, in each embodiment, the circuit body 100, 100A (see Figure 2 , Figure 3 )、air conditioner 200 (refer to Figure 4 ) are described, but the present disclosure is not limited to these descriptions, and various changes can be made. For example, in the first embodiment, the second variable resistor 6 N (Refer to Figure 2 )、Surge absorber 7 (refer to Figure 2 ) is provided in the noise filter circuit 10 (ie, the noise filter substrate B2: refer to Figure 1 ) is described, but is not limited thereto. Figure 6 The structure shown.

[0088] Figure 6 1 is a circuit diagram showing a structure of a circuit body 100B according to a first modification.

[0089] also, Figure 6 The structure is similar to the first embodiment (see Figure 2 ) is that the second variable resistor 6 N (Second surge protection element) The surge absorber 7 is not included in the noise filter circuit 10B, but is included in the power supply circuit 30B instead. That is, the second variable resistor 6 N , surge absorber 7 is mounted on inverter substrate B3 (refer to Figure 1 ). This structure also has the same effect as the first embodiment. In addition, by providing a second variable resistor 6 in the power supply circuit 30B N Etc., it is possible to improve the noise suppression effect in the power supply circuit 30.

[0090] Figure 7 100C is a circuit diagram showing a structure of a circuit body 100C according to a second modification.

[0091] also, Figure 7 The structure is similar to the first embodiment (see Figure 2) is that a fourth variable resistor 71 and a surge absorber 72 are added to the noise filter circuit 10C. The fourth variable resistor 71 and the surge absorber 72 have the function of suppressing a lightning surge when a lightning surge occurs between the R phase and the ground (grounding part), between the S phase and the ground, and between the T phase and the ground. Specifically, one end of the fourth variable resistor 71 is connected to the first variable resistor 1 R , 1 S , 1 T 、Discharge resistor 2 R , 2 S , 2 T , the first X capacitor 3 R , 3 S , 3 T The other end of the fourth variable resistor 71 is connected to the third neutral line 83 via the surge absorber 72 and the third neutral line 83 in sequence. N According to such a configuration, even when a lightning surge occurs between the R phase, S phase, T phase and the ground, the lightning surge can be suppressed by the fourth variable resistor 71 and the surge absorber 72, thereby improving the reliability of the circuit body 100C.

[0092] In addition, in normal times when no lightning surge occurs, the resistance value of the fourth variable resistor 71 and the like is quite large, so no current flows particularly through the fourth variable resistor 71 and the like. R , 1 S , 1 T The other end of the (first surge protection element) is connected to the neutral line 8 N becomes substantially insulated (i.e., the two are not connected), so Figure 7 In the structure, it is also possible to prevent the first variable resistor 1 R , 1 S , 1 T Apply overvoltage.

[0093] In addition, in each embodiment, although the common mode coil (not shown) is not particularly mentioned, the noise filter circuit 10 (see Figure 2 ) can also be provided with a common mode coil. For example, in a three-phase power line 8 R , 8 S , 8 T In the Y capacitor 4 R , 4 S , 4 T A common mode coil is provided on one or both sides of the MOSFET. This further improves the effect of suppressing common mode noise.

[0094] In each embodiment, the first variable resistor 1 R , 1 S , 1 TThe case of the "first surge protection element" has been described, but it is not limited to this. That is, as the "first surge protection element", a Zener diode (TVS; Transient Voltage Suppressor) or an avalanche diode or other element may also be used. N The same applies to the third variable resistor 31 .

[0095] In each embodiment, the noise filter circuit 10 (see Figure 2 ) having a second variable resistor 6 N The structure of the surge absorber 7 has been described, but the second variable resistor 6 can be omitted as appropriate. N and one of the surge absorbers 7 .

[0096] In each embodiment, the noise filter circuit 10 (see Figure 2 ) having a first X capacitor 3 R , 3 S , 3 T 、Y capacitor 4 R , 4 S , 4 T , the second X capacitor 5 R , 5 S , 5 T Although the above description is given, some of them may be omitted as appropriate.

[0097] In each embodiment, the noise filter circuit 10 (see Figure 2 ) has three first variable resistors 1 R , 1 S , 1 T The case of the first variable resistor (first surge protection element) is described above, but is not limited to this. That is, the number of the first variable resistors may be four or more. In other words, the noise filter circuit 10 may have a structure having at least three first variable resistors (first surge protection elements). As a specific example, one end of a plurality of first variable resistors connected in series or in parallel may be connected to the power line 8 of the R phase. R In addition, the same is true for the other first variable resistors corresponding to the S phase and T phase.

[0098] In the first embodiment, the first variable resistor 1 R , 1 S , 1 T (Refer to Figure 2 ) and the other end of the discharge resistor 2 R , 2 S , 2 T (Refer to Figure 2 ), the first X capacitor 3R , 3 S , 3 T (Refer to Figure 2 ) are connected to each other, but are not limited thereto. R , 1 S , 1 T (Refer to Figure 2 ) and the other end of the discharge resistor 2 R , 2 S , 2 T (Refer to Figure 2 ), the first X capacitor 3 R , 3 S , 3 T (Refer to Figure 2 ) whose other ends are not connected to each other can also achieve the same effect as the first embodiment.

[0099] In the third embodiment, the circuit body 100 (see Figure 2 ) is set in outdoor unit U1 (refer to Figure 4 ) is described above, but is not limited thereto. For example, the circuit body 100 may also be provided in the indoor unit U2 (refer to Figure 4 ), and may also be provided in both the outdoor unit U1 and the indoor unit U2. That is, the circuit body 100 may be provided in at least one of the outdoor unit U1 and the indoor unit U2.

[0100] In addition, each embodiment can be combined as appropriate. For example, the circuit body 100A described in the second embodiment (see Figure 3 ) may also be provided in the outdoor unit U1 of the air conditioner 200 described in the third embodiment (see Figure 4 ).

[0101] In the third embodiment, the air conditioner 200 (see Figure 4 ) is equipped with a four-way valve 67 (refer to Figure 4 That is, the four-way valve 67 may be omitted from the air conditioner 200, and the air conditioner 200 may be configured to be a cooling-only or heating-only structure.

[0102] In the third embodiment, the outdoor unit U1 (see Figure 4 ) and indoor unit U2 (refer to Figure 4 ) are described above, but are not limited to this. That is, multiple indoor units connected in parallel may be provided, and multiple outdoor units connected in parallel may also be provided.

[0103] In the third embodiment, the air conditioner 200 (see Figure 4) is described for indoor air conditioning, but the third embodiment can also be applied to various air conditioners such as commercial air conditioners and multi-split air conditioners for buildings.

[0104] In the third embodiment, the device receiving AC power in the three-phase four-wire system is the air conditioner 200 (see Figure 4 That is, as long as it is a device that receives AC power supply in a three-phase four-wire system, each embodiment can be applied to various devices such as a water heater, a refrigerator, and a washing machine.

[0105] In addition, each embodiment is described in detail to explain the present disclosure in an easy-to-understand manner, and is not necessarily limited to having all the structures described. In addition, for a part of the structure of the embodiment, other structures can be added, deleted, or replaced.

[0106] In addition, the above-mentioned mechanisms and structures show the structures considered necessary for explanation, and do not necessarily show all the mechanisms and structures in the product.

[0107] Description of Reference Numerals

[0108] 1 R , 1 S , 1 T First variable resistor (first surge protection element)

[0109] 2 R , 2 S , 2 T Discharge resistor

[0110] 3 R , 3 S , 3 T First X capacitor (X capacitor)

[0111] 4 R , 4 S , 4 T Y capacitors

[0112] 5 R , 5 S , 5 T Second X capacitor

[0113] 6N second variable resistor (second surge protection element)

[0114] 7Surge absorber

[0115] 8 R ,81 R , 8 S , 8 T Power lines

[0116] 8N Neutral

[0117] 10, 10A, 10B, 10C Noise Filter Circuits

[0118] 20 Inverter circuit

[0119] 30, 30B power supply circuit

[0120] 40 Instantaneous power failure detection circuit

[0121] 50 200V system load

[0122] 71 fourth variable resistor

[0123] 72 Surge Absorber

[0124] 81 N First neutral line

[0125] 82 N Second neutral line

[0126] 83 N Third neutral line

[0127] 100, 100A, 100B, 100C circuit body

[0128] 200 air conditioner

[0129] B1 Terminal Block

[0130] B2 Noise Filter Substrate

[0131] B3 inverter substrate

[0132] B4 control board

[0133] E1 AC Power Supply

[0134] M1 Motor

[0135] Q1 Refrigerant circuit

[0136] U1 outdoor unit

[0137] U2 Indoor Unit

[0138] X1 electric box.

Claims

1. A circuit body, characterized in that: have: A noise filter circuit is connected to a three-phase four-wire AC power supply; an inverter circuit connected to the output side of the noise filter circuit via a three-phase power line different from a neutral line; as well as a power supply circuit to which a single-phase AC voltage is applied via one of the three-phase power lines and the neutral line, The noise filter circuit has at least three first surge protection elements, One end of each of the first surge protection elements is connected to the three-phase power lines respectively, and the other end is not connected to the neutral line and is not grounded.

2. The circuit body according to claim 1, characterized in that: The other ends of the first surge protection elements are connected to each other.

3. The circuit body according to claim 1, characterized in that: The neutral line has: A first neutral line, one end of which is connected to the terminal block and the other end of which is grounded; and A second neutral line has one end connected to the first neutral line and the other end connected to the power supply circuit. A second surge protection element is provided on the first neutral line.

4. The circuit body according to claim 3, characterized in that: The circuit body includes a noise filter substrate on which the noise filter circuit is mounted. The second surge protection element is mounted on the noise filter substrate.

5. The circuit body according to claim 3, characterized in that: The circuit body includes an inverter substrate on which the inverter circuit and the power supply circuit are mounted. The second surge protection element is mounted on the inverter substrate.

6. The circuit body according to claim 1, characterized in that: The other end of each of the first surge protection elements is connected to any one of the three-phase power lines so that the line voltage of the AC power source is applied to the first surge protection element. The noise filter circuit also has: a discharge resistor, one end of which is individually connected to the three-phase power lines correspondingly; and X capacitors, one end of which is connected to the three-phase power lines respectively. The other ends of the discharge resistor and the X capacitor are connected to each other.

7. An air conditioner, characterized in that: The air conditioner includes the circuit body according to any one of claims 1 to 6, and includes an outdoor unit and an indoor unit connected to the outdoor unit via a refrigerant pipe. The circuit body is provided in at least one of the outdoor unit and the indoor unit.

Images