CN111837204A

CN111837204A - Resistor device and converter device

Info

Publication number: CN111837204A
Application number: CN201980006020.0A
Authority: CN
Inventors: 原田圭司; 景山正则; 中岛浩二; 白形雄二; 野月善一; 内藤隆史; 吉村章; 有贺善纪
Original assignee: Koa Corp; Mitsubishi Electric Corp
Current assignee: Koa Corp; Mitsubishi Electric Corp
Priority date: 2018-03-19
Filing date: 2019-03-15
Publication date: 2020-10-27
Also published as: TWI695397B; TW201939546A; JP6984002B2; WO2019181774A1; JPWO2019181774A1

Abstract

The invention aims to provide a resistor device which is small in size and does not deteriorate the service life of a capacitor. The resistor device of the present invention includes: at least one resistor body (61) connected in series with the smoothing capacitor (5a) and the smoothing capacitor (5b) connected in series; a resistor (62a) connected in parallel with the smoothing capacitor (5 a); a resistor (62b) connected in parallel with the smoothing capacitor (5 b); and an insulating case (50) in which the resistors (61, 62a, 62b) are sealed by a sealing material (56) filled therein.

Description

Resistor device and converter device

Technical Field

The present invention relates to a resistor device.

Background

The conventional resistor device includes an inrush current prevention resistor and a voltage balancing resistor. These two types of resistors are fixed to the printed wiring board or the housing, respectively.

The inrush current prevention resistor suppresses an inrush current flowing to the capacitor when the input power is turned on. A relay is connected in parallel to the inrush current prevention resistor, and the current flowing through the inrush current prevention resistor is bypassed by switching the relay from off to on after the capacitor is charged.

In the case where a plurality of capacitors are connected in series in order to compensate for a shortage in withstand voltage of the capacitors, the voltages applied to the capacitors may become unbalanced due to variations in leakage current of the capacitors. To prevent this, a voltage balancing resistor is connected in parallel to each capacitor.

Patent document 1 discloses a resistor device including a resistor for normal discharge and a resistor for rapid discharge having a smaller resistance value than the resistor for normal discharge. Normally, the resistor for discharge is used as an inrush current prevention resistor, and the resistor for rapid discharge is used as a voltage balancing resistor.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-36145

Disclosure of Invention

Problems to be solved by the invention

In order to suppress the rush current of the capacitor, the rush current prevention resistance is required to have pulse resistance. The larger the capacity of the capacitor is, the larger the size of the inrush current prevention resistor becomes. Therefore, there is a problem that the inrush current prevention resistor needs a resistor body having a large size even though it is used only when the input power is turned on.

On the other hand, the voltage balance resistor generates heat stably, and the ambient temperature of the capacitor is increased, which causes a problem of deterioration in the lifetime of the capacitor.

In view of the above problems, it is an object of the present invention to provide a resistor device which is small in size and does not deteriorate the life of a capacitor.

Means for solving the problems

The resistor device of the present invention includes: at least one first resistor connected in series to the first smoothing capacitor and the second smoothing capacitor connected in series; a second resistor connected in parallel to the first smoothing capacitor; a third resistor connected in parallel to the second smoothing capacitor; and an insulating case in which the first, second, and third resistors are sealed with a sealing material filled therein.

Effects of the invention

According to the resistor device of the present invention, the first, second, and third resistors are thermally coupled by being sealed in the insulating case. Since the first, second, and third resistors have different timings of temperature rise, when the temperature of one resistor rises, the other resistor can cool the heat generation. Therefore, the first, second, and third resistors can be miniaturized, and the resistor device can be miniaturized. In addition, although the second and third resistors stably generate heat when used as a voltage balance resistor, the heat can be dissipated to the first resistor, and deterioration in the lifetime of the capacitor can be suppressed. The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

Drawings

Fig. 1 is a circuit diagram of an inverter (inverter) device according to embodiment 1.

Fig. 2 is a diagram showing temperature changes of the inrush current prevention resistor and the voltage balancing resistor.

Fig. 3 is a perspective view of an inverter device according to embodiment 1.

Fig. 4 is a side view of the inverter device according to embodiment 1.

Fig. 5 is an exploded perspective view of the resistor device according to embodiment 1.

Fig. 6 is a sectional view of the resistor device according to embodiment 1.

Fig. 7 is an exploded perspective view of a resistor device according to embodiment 2.

Fig. 8 is an exploded perspective view of a resistor device according to embodiment 3.

Fig. 9 is a sectional view of a resistor device according to embodiment 3.

Detailed Description

Embodiment 1.

Fig. 1 is a circuit diagram of an inverter device 100 according to embodiment 1. The inverter device 100 includes a three-phase (R-phase, S-phase, and T-phase) input power supply Pin, a rectifier circuit 10, an inrush current prevention resistor 4, an inrush current prevention relay 3, a relay drive circuit 2,

smoothing capacitors

5a and 5b,

voltage balance resistors

6a and 6b, and an inverter 20.

The rectifier circuit 10 includes a plurality of rectifier diodes 1a, 1b, 1c, 1d, 1e, and 1 f. Rectifier diodes 1a and 1d are connected to the R phase, rectifier diodes 1b and 1e are connected to the S phase, and rectifier diodes 1c and 1f are connected to the T phase. Smoothing capacitor 5a and smoothing capacitor 5b are connected in series between positive electrode line Lp and negative electrode line Ln in order to ensure a withstand voltage. The inrush current prevention resistor 4 is connected in series to the series-connected body at the subsequent stage of the rectifier circuit 10. The inrush current prevention relay 3 is connected in parallel to an inrush current prevention resistor 4, and its on/off is controlled by the relay drive circuit 2.

The rush current prevention resistor 4 is used to limit the charging current flowing through the smoothing

capacitors

5a, 5 b. If there is no inrush current prevention resistor 4, an excessive inrush current flows to the

uncharged smoothing capacitors

5a and 5b when the input power supply Pin is turned on. When the

smoothing capacitors

5a and 5b are charged, the inrush current prevention relay 3 is operated to shift from off to on by the relay drive circuit 2, and the current that has previously passed through the inrush current prevention resistor 4 bypasses the inrush current prevention resistor 4 via the inrush current prevention relay 3. Therefore, no current flows through the inrush current prevention resistor 4.

Since the voltage division ratio of the

smoothing capacitors

5a and 5b depends on the leakage currents of the

smoothing capacitors

5a and 5b, the applied voltages of the

smoothing capacitors

5a and 5b vary due to variations in the leakage currents. In order to suppress variations in applied voltage,

voltage balance resistors

6a and 6b are connected in parallel to the

smoothing capacitors

5a and 5b, respectively. The voltage is applied to the

voltage balance resistors

6a and 6b at the same time as the charging of the

smoothing capacitors

5a and 5b is started, but the temperature of the

voltage balance resistors

6a and 6b rises little by little because the value of the current flowing through the

voltage balance resistors

6a and 6b is small.

Inverter 20 includes IGBTs (Insulated Gate Bipolar transistors) 7a, 7b, 7c, 7d, 7e, and 7f, diodes 8a, 8b, 8c, 8d, 8e, and 8f, and

driving circuits

9a, 9b, 9c, 9d, 9e, and 9 f. The IGBT is an example of a power semiconductor element. Between the positive line Lp and the negative line Ln, there are connected: a series circuit composed of IGBTs 7a, 7d for switching the U phase; a series circuit composed of IGBTs 7b, 7e for switching the V phase; and a series circuit composed of IGBTs 7c, 7f for switching W phase. The IGBTs 7a, 7b, 7c, 7d, 7e, and 7f are connected with diodes 8a, 8b, 8c, 8d, 8e, and 8f in antiparallel, respectively. The junction points of the IGBTs 7a, 7d are connected to a U-phase terminal U of the motor, the junction points of the IGBTs 7b, 7e are connected to a V-phase terminal V of the motor, and the junction points of the IGBTs 7c, 7f are connected to a W-phase terminal W of the motor. Drive signals are supplied separately from the

drive circuits

9a, 9b, 9c, 9d, 9e, and 9f to the gates and emitters of the IGBTs 7a, 7b, 7c, 7d, 7e, and 7f, respectively. The

drive circuits

9a, 9b, 9c, 9d, 9e, and 9f include photo couplers for optical insulation, receive control signals from an external control circuit such as a microprocessor, generate drive signals, and supply the drive signals to the gates and emitters of the IGBTs 7a, 7b, 7c, 7d, 7e, and 7f via connection terminals.

Although the inverter device 100 for converting the three-phase (R-phase, S-phase, and T-phase) input power source Pin into three-phase (U-phase, V-phase, and W-phase) power and outputting the power is illustrated in fig. 1, the present invention can be applied to other various inverter devices or various converter devices. In fig. 1, the inrush current prevention resistor 4 and the inrush current prevention relay 3 are disposed at the rear stage of the rectifier circuit 10, but may be disposed at the U-phase, V-phase, and W-phase of the input power supply Pin at the front stage of the rectifier circuit 10.

Referring to fig. 2, a description will be given of temperature changes of the rush current prevention resistor 4 and the

voltage balance resistors

6a and 6 b. In fig. 2, a curve 41 shows a temperature change of the inrush current prevention resistance 4, and a curve 42 shows a temperature change of the

voltage balancing resistances

6a, 6 b. In the inverter device 100 according to embodiment 1, the inrush current prevention resistor 4 and the

voltage balancing resistors

6a and 6b are thermally coupled as described later in fig. 5 and 6, but fig. 2 shows a state in which the inrush current prevention resistor 4 and the

voltage balancing resistors

6a and 6b are not thermally coupled, that is, a temperature change in a state in which no thermal movement is assumed between the inrush current prevention resistor 4 and the

voltage balancing resistors

6a and 6 b.

First, a temperature change of the inrush current prevention resistor 4 shown by the curve 41 will be described. When the input power supply Pin is turned on at time T equal to 0, the temperature of the inrush current prevention resistor 4 rises sharply. This is because the charging of the smoothing

capacitors

5a and 5b is started and the inrush current to the smoothing

capacitors

5a and 5b is limited by the inrush current preventing resistor 4. As the smoothing

capacitors

5a and 5b are charged, the current flowing through the inrush current prevention resistor 4 becomes smaller. When the inrush current protection relay 3 is shifted from off to on at time T-T1, the current bypasses the inrush current protection resistor 4 through the inrush current protection relay 3, and the temperature of the inrush current protection resistor 4 decreases. In this way, since a large current flows through the inrush current prevention resistor 4 only in a short time when the smoothing

capacitors

5a and 5b are charged, a wire resistor or the like having high pulse resistance is used.

Next, the temperature change of the

voltage balance resistors

6a and 6b indicated by the curve 42 is examined. When the input power supply Pin is turned on at time T equal to 0, the charging of the smoothing

capacitors

5a and 5b is started, and at the same time, the voltage is applied to the

voltage balance resistors

6a and 6 b. However, since the value of the current flowing through the

voltage balance resistors

6a and 6b is small, the temperature of the

voltage balance resistors

6a and 6b increases little by little.

When the temperature changes of the rush current prevention resistor 4 and the

voltage balance resistors

6a and 6b are compared, the timings of temperature increases of the two resistors are different. At the time point (T — T1) when the temperature of the inrush current prevention resistor 4 reaches the peak, the temperature of the

voltage balance resistors

6a and 6b does not increase greatly. Conversely, when the temperature of the

voltage balance resistors

6a and 6b is high, the temperature of the inrush current prevention resistor 4 decreases by passing through a peak.

Fig. 3 is a perspective view of the inverter device 100, and fig. 4 is a side view of the inverter device 100 as viewed in the direction of the arrow shown in fig. 3. In the inverter device 100, the inrush current prevention relay 3 (not shown), the smoothing

capacitors

5a and 5b, the resistor device 30A, the

drive circuits

9a, 9b, 9c, 9d, 9e, and 9f (not shown), and the relay drive circuit 2 (not shown) are mounted on the upper surface of the printed wiring board 33, and the rectifier module 31 and the IGBT module 32 are mounted on the lower surface. The rectifier module 31 and the IGBT module 32 are electrically connected to the printed wiring board 33 by soldering.

The rectifier module 31 is a module in which a plurality of diodes 1a, 1b, 1c, 1d, 1e, and 1f are packaged in one package at the same time, and constitutes the rectifier circuit 10. The IGBT module 32 is a module in which the IGBTs 7a, 7b, 7c, 7d, 7e, 7f and the diodes 8a, 8b, 8c, 8d, 8e, 8f are packaged together in one package. Since the rectifier module 31 and the IGBT module 32 are heat-generating electronic components, they are mounted with a heat sink 34, and are cooled by the heat sink 34.

The structure of the resistor device 30A will be explained. Fig. 5 is an exploded perspective view of the resistor device 30A, and fig. 6 is a sectional view a-a in a state where the resistor device 30A of fig. 5 is assembled. The resistor device 30A includes

resistors

61, 62a, 62b and an insulating case 50. The resistor 61 is used as the inrush current preventing resistor 4, and the

resistors

62a and 62b are used as the

voltage balancing resistors

6a and 6 b.

The insulating case 50 has a rectangular parallelepiped shape, and

grooves

53, 54, and 55 recessed from the upper surface are formed. Resistor 61 is disposed in groove 53, and

resistors

62a and 62b are disposed in

grooves

54 and 55, respectively. In other words, groove 53 is a first groove in which resistor 61 is disposed, groove 54 is a second groove in which resistor 62a is disposed, and groove 55 is a third groove in which resistor 62b is disposed. This makes it easy to position the

resistors

62a, 62b, and 62c in the insulating case 50, and thus, positional displacement of the

resistors

62a, 62b, and 62c can be suppressed. The

resistors

61, 62a, 62b have a cylindrical shape. Electrode terminals 52c are connected to both ends of resistor 61, electrode terminals 52a are connected to both ends of resistor 62a, and electrode terminals 52b are connected to both ends of resistor 63 b.

In fig. 5, the size of the inrush current prevention resistor 4 is made larger than the

voltage balance resistors

6a and 6b, and the groove 53 in which the inrush current prevention resistor 4 is disposed is made larger than the

grooves

54 and 55 in which the

voltage balance resistors

6a and 6b are disposed. This prevents the inrush current preventing resistor 4 from being erroneously disposed in the

slots

54 and 55 in which the

voltage balancing resistors

6a and 6b are disposed.

In a state where

resistors

61, 62a, and 62b are arranged in

grooves

53, 54, and 55, sealing material 56 such as a sealant is filled in

grooves

53, 54, and 55. In this way, the

resistors

61, 62a, 62b are sealed in the insulating case 50 and thermally coupled. That is, the inrush current prevention resistor 4 is thermally coupled to the

voltage balancing resistors

6a and 6 b. As shown in fig. 6, the sealing amount of the sealing material 56 is adjusted so that the sealing surface, i.e., the upper surface of the sealing material 56 is lower than the upper surface of the insulating housing 50. This increases the creepage distance between the

electrode terminals

52a, 52b, and 52c by the distance between the upper surface of the insulating case 50 and the sealing surface of the sealing material 56. Similarly, the creepage distances between the

electrode terminals

52a, 52b, and 52c and the housing 40 to which the resistor device 30A is attached become longer.

The

electrode terminals

52a, 52b, and 52c protrude upward from the insulating case 50, and the protruding portions are connected to the printed wiring board 33 using a connector such as a flat connector and wiring (see fig. 3). More specifically, the electrode terminals 52c are wired to connection points 70c shown at both ends of the resistor 61 in fig. 1. The electrode terminals 52a are wired to connection points 70a shown at both ends of the resistor 62a in fig. 1. The electrode terminals 52b are wired to connection points 70b shown at both ends of the resistor 62b in fig. 1. If the shape or size is changed between the electrode terminal 52c and the

electrode terminals

52a, 52b, it is possible to prevent erroneous connection when the

electrode terminals

52a, 52b, 52c are connected to the

connection points

70a, 70b, 70c using a connector such as a flat connector.

The resistor device 30A is attached with a fitting 51 having a screw hole 57. By screwing the fitting 51 to the housing 40, the resistance device 30A is fixed in a state where the bottom surface thereof is in direct contact with the housing 40. This allows heat generated by the resistor device 30A to be released to the housing 40 of the inverter device 100, thereby enabling the resistor device 30A to be reduced in size. In addition, the resistor device 30A may be attached to a side surface of the housing 40 or the heat sink 34, in addition to the bottom surface of the housing 40, and similar effects can be obtained. In addition, the fixing method of the resistance device 30A is not limited to the above method. The resistor device 30A may be mounted on the printed wiring board 33 by inserting the

electrode terminals

52a, 52b, and 52c into through holes provided in the printed wiring board 33 and soldering the electrode terminals to the printed wiring board 33.

As described above, the resistance device 30A according to embodiment 1 includes: a resistor body 61 as a first resistor body connected in series with a smoothing capacitor 5a as a first smoothing capacitor and a smoothing capacitor 5b as a second smoothing capacitor connected in series; a resistor 62a as a second resistor connected in parallel with the smoothing capacitor 5 a; a resistor 62b as a third resistor connected in parallel with the smoothing capacitor 5 b; and an insulating case 50 in which the

resistors

61, 62a, and 62b are sealed with a sealing material 56 filled therein. Thereby, the inrush current prevention resistor 4 is thermally coupled to the

voltage balance resistors

6a and 6 b. As shown in fig. 2, the inrush current preventing resistor 4 and the

voltage balancing resistors

6a and 6b have different timings of temperature rise, and the temperatures of the

voltage balancing resistors

6a and 6b do not rise when the temperature of the inrush current preventing resistor 4 rises. Therefore, the heat generated by the inrush current preventing resistor 4 moves to the

voltage balancing resistors

6a and 6b, and thereby an effect equivalent to an increase in the heat capacity of the inrush current preventing resistor 4 can be obtained, and a temperature increase of the inrush current preventing resistor 4 can be suppressed. When the temperature of the

voltage balance resistors

6a and 6b rises, the temperature of the inrush current prevention resistor 4 does not rise. Therefore, the heat generated by the

voltage balance resistors

6a and 6b moves to the inrush current prevention resistor 4, and thereby an effect equivalent to an increase in the heat capacity of the

voltage balance resistors

6a and 6b can be obtained, and the temperature rise of the

voltage balance resistors

6a and 6b can be suppressed. As a result, the inrush current prevention resistor 4 and the

voltage balancing resistors

6a and 6b can be downsized. Further, since the temperature rise of the

voltage balance resistors

6a and 6b is suppressed, the temperature rise around the smoothing

capacitors

5a and 5b is suppressed, and the deterioration of the life of the smoothing

capacitors

5a and 5b is suppressed.

Embodiment 2.

Fig. 7 is an exploded perspective view of a resistor device 30B according to embodiment 2. The resistor device 30B is a partially modified resistor device 30A of embodiment 1, and therefore, differences from the resistor device 30A of embodiment 1 will be described below. In the resistor device 30A according to embodiment 1, as shown in fig. 5, the

resistors

62a and 62b serving as the

voltage balance resistors

6a and 6b are disposed in the

different grooves

54 and 55 of the insulating case 50. In contrast, in the resistance device 30B according to embodiment 2, the ends of the resistors 62a and 62B having the same potential are connected by the common electrode terminal 52d, and the resistors 62a and 62B are disposed in the same groove 58. Otherwise, the resistor device 30B is the same as the resistor device 30A of embodiment 1.

In the resistor device 30B according to embodiment 2, one end of the resistor 62a and one end of the resistor 62B are connected by the common electrode terminal 52d, and the insulating case 50 has the groove 53 as the first groove in which the resistor 61 is disposed and the groove 58 as the second groove in which the resistors 62 and 63 are disposed. By providing the end portions of the resistors 62a and 62B having the same potential as the common electrode terminal 52d, the resistor device 30B can be reduced in size and the number of components can be reduced. Since the

voltage balance resistors

6a and 6b can be mounted at a closer distance, the

voltage balance resistors

6a and 6b receive heat, and the temperature difference therebetween is reduced. Therefore, variations in the resistance values of the

voltage balance resistors

6a and 6b due to temperature changes of the

resistors

62a and 62b can be reduced.

Embodiment 3.

Fig. 8 is an exploded perspective view of a resistor device 30C according to embodiment 3, and fig. 9 is a B-B sectional view in which the resistor device 30C of fig. 8 is assembled. Hereinafter, the configuration of the resistor device 30C is compared with the resistor device 30B according to embodiment 2, and the difference will be described. The configuration of the resistor device 30C, which is not particularly described in the following description, is the same as that of the resistor device 30B of embodiment 2.

In the resistor device 30B according to embodiment 2, one resistor 61 constitutes the inrush current protection resistor 4, but in the resistor device 30C, two resistors 61 are connected in series or in parallel to constitute the inrush current protection resistor 4. In the resistor device 30B according to embodiment 2, the resistor 61 constituting the inrush current prevention resistor 4 and the resistors 62a and 62B constituting the voltage balance resistors 6a and 6B are disposed in

different grooves

53 and 58. However, in the resistor device 30C, the

resistors

61, 62a, and 62b are arranged in the same groove 59 provided in the insulating case 50. The groove 59 is a concave portion recessed from the upper surface of the insulating housing 50.

Two projections 60 are provided from one end to the other on the bottom surface of the groove 59. With the two projections 60 thus arranged, the groove 59 of the insulating housing 50 is divided into three regions, i.e., a region sandwiched between the two projections 60, a region sandwiched between the side surfaces of one projection 60 and the groove 59, and a region sandwiched between the side surfaces of the other projection 60 and the groove 59. The

resistors

62a and 62b are disposed in a region sandwiched by the two protrusions 60, and the two resistors 61 are disposed in the other region so as to sandwich the

resistors

62a and 62 b. The resistor 61 is not in contact with the

resistors

62a and 62b by the projection 60, and the grooves 59 of the

resistors

61, 62a, and 62b are positioned.

In a state where the

resistors

61, 62a, and 62b are arranged in the groove 59, the groove 59 is filled with a sealing material 56 such as a sealant. As shown in fig. 9, the sealing amount of the sealing material 56 is adjusted so that the sealing surface, i.e., the upper surface of the sealing material 56 is lower than the upper surface of the insulating housing 50. In this way, the

resistors

voltage balancing resistors

6a and 6 b.

By providing the protrusions 60 on the bottom surfaces of the grooves 59 of the insulating case 50 and positioning the

resistors

61, 62a, and 62b by the protrusions 60, the material of the insulating case 50 can be reduced as compared with embodiments 1 and 2, and the manufacturing can be facilitated. Further, since the resistor 61 constituting the inrush current prevention resistor 4 is disposed so as to sandwich the

resistors

62a and 62b constituting the

voltage balance resistors

6a and 6b, the thermal coupling between the inrush current prevention resistor 4 and the

voltage balance resistors

6a and 6b is improved, the effect of cooling the heat generated by the

resistors

62a and 62b by the resistor 61 and the heat generated by the resistor 61 by the

resistors

62a and 62b is improved.

In the present embodiment, the inrush current prevention resistor 4 is formed by a plurality of resistors 61, and the resistors 61 are disposed on both sides of the

resistors

62a and 62b forming the

voltage balance resistors

6a and 6 b. However, the inrush current prevention resistor 4 may be formed by one resistor 61, the voltage balance resistor 6a may be formed by a plurality of resistors 62a, the voltage balance resistor 6b may be formed by a plurality of resistors 62b, and the

resistors

62a and 62b may be arranged so as to sandwich the resistor 61. However, since the

resistors

62a and 62b are at a higher temperature for a longer period of time than the resistor 61, the uniform heating of the resistor device 30C is achieved if the

resistors

62a and 62b are disposed near the center of the insulating case 50.

In the present invention, the embodiments may be freely combined or may be appropriately modified or omitted within the scope of the invention.

Description of the reference numerals

1a, 1b, 1c, 1d, 1e, 1f rectifier diodes; 2a relay drive circuit; 3 surge current prevention relay; 4 rush current prevention resistance; 5a, 5b smoothing capacitors; 6a, 6b voltage balancing resistors; 7a, 7b, 7c, 7d, 7e, 7f IGBTs; 8a, 8b, 8c, 8d, 8e, 8f diodes; 9a, 9b, 9c, 9d, 9e, 9f drive circuits; 10 a rectifier circuit; 20 a converter; 30A, 30B, 30C resistor means; 31 a rectification module; a 32IGBT module; 33 a printed wiring board; 34 a heat sink; 40 a frame body; 51, a fitting; 52a, 52b, 52c, 52d electrode terminals; 53. 54, 55, 58, 59 slots; 56 a sealing material; 57 threaded holes.

Claims

1. A resistor device (30A) is provided with:

at least one first resistor (61) connected in series with a first smoothing capacitor (5a) and a second smoothing capacitor (5b) connected in series;

a second resistor (62a) connected in parallel to the first smoothing capacitor (5 a);

a third resistor (62b) connected in parallel to the second smoothing capacitor (5 b); and

and an insulating case (50) in which the first, second, and third resistors (61, 62a, 62b) are sealed with a sealing material (56) filled therein.

2. The resistive device (30A) of claim 1,

electrode terminals (52a, 52b, 52c) are connected to the first, second and third resistors (61, 62a, 62b),

the electrode terminals (52a, 52b, 52c) protrude from the upper surface of the insulating case (50),

the upper surface of the sealing material (56) filled in the insulating case (50) is positioned below the upper surface of the insulating case (50).

3. The resistive device (30A) of claim 1 or 2,

at least one groove (53, 54, 55) recessed from an upper surface of the insulating housing (50) is provided in the insulating housing (50),

the first, second, and third resistors (61, 62a, 62b) are disposed in the grooves (53, 54, 55).

4. The resistive device (30A) of claim 3,

the tank has:

a first groove (53) in which the first resistor (61) is disposed;

a second groove (54) in which the second resistor (62a) is disposed; and

and a third groove (55) in which the third resistor (62b) is disposed.

5. The resistive device (30B) of claim 3,

one end of the second resistor (62a) and one end of the third resistor (62b) are connected by a common terminal (52d),

the tank has:

a first groove (53) in which the first resistor (61) is disposed; and

and a second groove (58) in which the second and third resistors (62a, 62b) are arranged.

6. The resistive device (30C) of claim 3,

the first, second and third resistors (61, 62a, 62b) are arranged in one groove (59) formed in the insulating case (50),

the insulating case (50) has, on the bottom surface of the groove (59), a protrusion (60) for positioning the first, second, and third resistors (61, 62a, 62 b).

7. The resistive device (30C) of any of claims 1-6,

the plurality of first resistors (61) are connected in series or in parallel, and are arranged so as to sandwich the second and third resistors (62a, 62 b).

8. The resistive device of any of claims 1 through 6,

the second and third resistors (62a, 62b) are arranged so as to sandwich the first resistor (61).

9. A transducer arrangement (100) in which,

a resistor device according to any one of claims 1 to 8.