Variable frequency driver

Abstract

The utility model relates to the technical field of variable frequency driving, and discloses a variable frequency driver, which comprises a control circuit board, a radiator and at least one group of discrete power devices. A rectifying circuit, a controller and at least one driving chip are arranged on the control circuit board, the discrete power devices in the same group form a group of inverter circuits, and the inverter circuits invert direct current output by the rectifying circuit into alternating current with adjustable frequency and voltage to a load. The output end of the driving chip is electrically connected with the control end of the corresponding discrete power device, and the driving chip is electrically connected with the controller and is controlled by the controller. The discrete power device is fixedly installed on the radiator, the control circuit board is provided with a bonding pad used for being welded with a pin of the discrete power device, and the discrete power device is electrically connected with the control circuit board by welding the pin of the discrete power device with the bonding pad. According to the driver, heat generated by the discrete power device can be prevented from being transmitted to the controller and the driving chip on the control circuit board, and the stability of the driver is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to variable frequency drive technical field, concretely relates to a variable frequency drive. BACKGROUND

[0002] The warm and hot industry equipment, such as air conditioner, heat pump, liquid cooling, refrigerator and dryer etc., and some household appliances, such as household air conditioner, refrigerator etc., need to drive compressor, fan motor and other motors to work through variable frequency drive, to realize stepless speed regulation of compressor or fan by converting direct current into alternating current with variable frequency and voltage, to realize variable frequency control of equipment. The inverter part can be realized by intelligent power module (IPM), or composed of driving chip and IGBT device or MOSFET device, etc. The latter has the advantages of lower cost, and the large heat generating discrete power devices can be centrally arranged, which is convenient for heat management of the drive. In order to improve the heat dissipation efficiency, the existing part of variable frequency drive directly installs the radiator on the back of the circuit board, and the discrete power devices are centrally arranged in the area of the front of the circuit board facing the radiator, so that the heat generated by the discrete power devices can be quickly transmitted to the back of the radiator through the circuit board, to improve the heat dissipation efficiency of the drive. But the heat generated by the discrete power devices still has part transmitted to the driving chip of the controller through the circuit board, which may affect the stability of the controller and the driving chip. SUMMARY

[0003] In order to overcome the defects of the prior art, the purpose of the utility model is to provide a variable frequency drive board, which can avoid the heat generated by the discrete power devices from being transmitted to the controller and the driving chip, and further improve the stability of the drive.

[0004] To solve the above problems, the utility model adopts the following technical scheme: a variable frequency drive, comprising a control circuit board, a radiator and at least one group of discrete power devices, the control circuit board is provided with a rectifier circuit, a controller and at least one driving chip, the discrete power devices of the same group constitute an inverter circuit, the input end of the rectifier circuit is electrically connected with external power supply, the input end of the inverter circuit is electrically connected with the output end of the rectifier circuit, the output end of the inverter circuit is connected with load, the output end of the driving chip is electrically connected with the control end of the discrete power device in the corresponding inverter circuit, the driving chip is electrically connected with the controller and is controlled by the controller, the discrete power device is fixedly installed on the radiator, the control circuit board is provided with a solder pad for welding with the pin of the discrete power device, the discrete power device is electrically connected with the control circuit board by welding its pin with the solder pad.

[0005] Compared with the prior art, the utility model discloses the beneficial effect lies in: the frequency conversion driver, directly install discrete power device on radiator, and through the solder pad with control circuit board electric connection, thereby with the other discrete power device of same group, drive chip composition inverter circuit, realize the frequency conversion control of load under the control of controller. Since discrete power device is directly installed on radiator, is not arranged on control circuit board, and the heat of discrete power device during working process will directly dissipate through radiator, will not be passed to controller and drive chip on control circuit board through control circuit board, thereby can make controller and drive chip work more stably, improve the stability of frequency conversion driver.

[0006] The frequency conversion driver, the discrete power device is detachably installed on the radiator through a screw.

[0007] The frequency conversion driver further includes a housing, the housing is provided with a mounting portion for mounting the radiator, the control circuit board is fixedly arranged on one side of the mounting portion, the mounting portion is provided with a window for exposing the end face of the radiator, and the discrete power device is fixedly installed on the end face of the radiator through the window.

[0008] The frequency conversion driver further includes a heat dissipation circuit board, the discrete power device is attached to a first face of the heat dissipation circuit board, a plurality of pin connectors are arranged on the first face of the heat dissipation circuit board, the pin connectors are electrically connected with the corresponding discrete power devices, the control circuit board is arranged on one side of the first face of the heat dissipation circuit board, a gap is formed between the control circuit board and the heat dissipation circuit board, the pin connectors are welded with the solder pads, and a second face of the heat dissipation circuit board is connected with the radiator.

[0009] The frequency conversion driver, the heat dissipation circuit board is an aluminum substrate.

[0010] The frequency conversion driver, a heat dissipation silicone coating is arranged between the heat dissipation circuit board and the end face of the radiator.

[0011] The frequency conversion driver, the heat dissipation circuit board is detachably installed on the end face of the radiator through a screw, a plurality of mounting avoiding holes are arranged on the control circuit board, and the plurality of mounting avoiding holes are arranged above the screw holes on the heat dissipation circuit board in a one-to-one correspondence.

[0012] The frequency conversion driver, a plurality of heat dissipation grid plates are arranged on the side of the radiator away from the discrete power devices.

[0013] The frequency conversion driver, the surface of the heat dissipation grid plate is wavy.

[0014] The variable frequency driver, the rectifier circuit comprises a rectifier bridge and a DC bus capacitor, the input end of the rectifier bridge is electrically connected with external power supply, the output end of the rectifier bridge is electrically connected with the input end of the inverter circuit, the DC bus capacitor is connected in parallel with the output end of the rectifier bridge, and the rectifier bridge is a single-phase rectifier bridge or a three-phase rectifier bridge.

[0015] The utility model will be described in further detail below in combination with the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is the circuit principle diagram of the variable frequency driver of the first embodiment of the utility model.

[0017] Figure 2 It is the circuit principle diagram of the variable frequency driver of the second embodiment of the utility model.

[0018] Figure 3 It is the structure schematic view of the variable frequency driver of the first embodiment of the utility model.

[0019] Figure 4 It is the structure schematic view of the shell of the first embodiment of the utility model.

[0020] Figure 5 It is the structure schematic view of the radiator of the first embodiment of the utility model.

[0021] Figure 6 It is Figure 5 It is the enlarged schematic view of A in the middle.

[0022] Figure 7 It is the structure schematic view of the radiating circuit board of the second embodiment of the utility model.

[0023] Figure 8 It is the structure schematic view of the variable frequency driver of the second embodiment of the utility model.

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] 100 control circuit board, 110 installation avoiding hole, 200 radiator, 210 radiating grid plate, 300 discrete power device, 400 shell, 410 installation part, 500 radiating circuit board, 510 pin connector. DETAILED DESCRIPTION

[0026] The embodiments of the utility model will be described in detail below.

[0027] Embodiment one: refer to Figure 1 And Figure 3The utility model discloses an embodiment one provides a kind of variable frequency drives, including control circuit board 100, radiator 200 and at least one group discrete power device 300.Discrete power device 300 of the same group constitutes a group of inverter circuit, the input end of rectifier circuit is electrically connected with external power supply, the input end of inverter circuit is electrically connected with the output end of rectifier circuit, and the output end of inverter circuit is connected with load.The output end of drive chip is electrically connected with the control end of discrete power device 300 in corresponding inverter circuit respectively, and drive chip is electrically connected with controller and is controlled by controller.Discrete power device 300 is fixedly installed on radiator 200, and solder pad for being welded with the pin of discrete power device 300 is arranged on control circuit board 100, and discrete power device 300 is electrically connected with control circuit board 100 by welding its pin with solder pad.The circuit part of inverter circuit is arranged on control circuit board 100, and discrete power device 300 is accessed to the inverter circuit of control circuit board 100 by welding with solder pad, and is electrically connected with other discrete power device 300 of same group, rectifier circuit and drive chip by printed circuit on control circuit board 100 to constitute inverter module, and the direct current output by rectifier circuit is inverter into frequency and voltage adjustable alternating current, to realize the variable frequency control to compressor or fan and other loads.

[0028] The variable frequency drive, by installing discrete power device 300 on radiator 200, and being electrically connected with control circuit board 100 by solder pad, avoids installing discrete power device 300 on control circuit board 100, avoids the heat generated in the working process of discrete power device 300 being transferred to drive chip and controller through circuit board, and affects the working stability of drive chip and controller.The variable frequency drive, most of the heat generated by discrete power device 300 is directly dissipated to air through radiator 200, and the pin of discrete power device 300 can only transfer a small part of heat to circuit board, avoids the temperature of drive chip and controller being too high, and improves the stability of variable frequency drive.

[0029] It can be understood that discrete power device 300 can be IGBT device or MOSFET device, in the embodiment, for the convenience of maintenance, discrete power device 300 is detachably installed on the end face of radiator 200. Figure 3 And Figure 4The variable frequency driver further comprises a shell 400, the shell 400 is provided with a mounting portion 410 for mounting the heat sink 200, the heat sink 200 is mounted on the mounting portion 410 by screws and is mounted on the outer side of the shell. The control circuit board 100 is fixedly arranged on the left side of the mounting portion 410, the mounting portion 410 is provided with a window through which the end surface of the heat sink 200 is exposed, the discrete power device 300 is fixedly mounted on the end surface of the heat sink 200 through the window, the pads on the control circuit board 100 are concentratedly arranged on the right side, and the discrete power device 300 is arranged side by side on the end surface of the heat sink 200 and the pins are uniformly directed to the control circuit board 100 on the left side so as to be welded with the pads on the control circuit board 100.

[0030] With reference to Figure 5 and Figure 6 In the embodiment, a plurality of heat dissipation grid plates 210 are vertically arranged on the side of the heat sink 200 away from the discrete power device 300, gaps are formed between the plurality of heat dissipation grid plates 210, a grid structure is formed, the heat exchange area of the heat sink 200 with external air is increased, and the heat dissipation efficiency of the discrete power device 300 is improved. The surface of the heat dissipation grid plate 210 is wavy, so as to further increase the contact area of the heat dissipation grid plate 210 with air, increase the heat exchange area of the heat sink 200, improve the heat dissipation efficiency of the discrete power device 300, and ensure the working stability of the variable frequency driver.

[0031] With reference to Figure 1 and Figure 2 It can be understood that the rectifier circuit is composed of a rectifier bridge BRD1 and a DC bus capacitor C1, the rectifier bridge BRD1 can be a single-phase rectifier bridge or a three-phase rectifier bridge, the input end of the rectifier bridge BRD1 is electrically connected with external power supply, the output end is electrically connected with the input end of the inverter circuit, and the DC bus capacitor C1 is connected in parallel with the output end of the rectifier bridge BRD1. It can be understood that the DC bus capacitor C1 can be a single electrolytic capacitor with large capacity or can be composed of a group of electrolytic capacitors with small capacity in parallel. It can be understood that the controller can be a single-chip microcomputer, a PLC or a programmable control device such as an FPGA and a DSP, the output end of the drive chip is connected with the gate electrode or the gate electrode of the discrete power device 300 through a PWM control signal.

[0032] Embodiment two: with reference to Figure 7 and Figure 8, the difference between embodiment two and embodiment one is that it further comprises a heat dissipation circuit board 500, the discrete power device 300 is attached on the heat dissipation circuit board 500, and a plurality of pin connectors 510 are also attached on the heat dissipation circuit board 500, the plurality of pin connectors 510 are respectively electrically connected with the plurality of discrete power devices 300 through the printed circuit on the heat dissipation circuit board 500, the heat dissipation circuit board 500 is welded with the pads on the control circuit board 100 through the pin connectors 510, so as to realize the electrical connection between the heat dissipation circuit board 500 and the control circuit board 100, thereby making the discrete power device 300 electrically connected with the control circuit board 100 to form an inverter module with the corresponding driving chip on the control circuit board 100. The discrete power device 300 and the pin connector 510 are both attached on the first surface of the heat dissipation circuit board 500, the second surface of the heat dissipation circuit board 500 is connected with the end surface of the heat sink 200, and the discrete power device 300 is arranged on the heat sink 200 through the heat dissipation circuit board 500. The control circuit board 100 is arranged on the side of the heat dissipation circuit board 500 away from the heat sink 200, and the control circuit board 100 has a gap with the heat dissipation circuit board 500. The frequency converter of the embodiment is arranged on the back side of the heat dissipation circuit board 500, and the heat dissipation circuit board 500 is welded with the control circuit board 100 through the pin connector 510, so as to have a gap with a certain width between the heat dissipation circuit board 500 and the control circuit board 100, thereby increasing the distance between the discrete power device 300 and the control circuit board 100, and further avoiding the heat generated by the discrete power device 300 from being transferred to the controller and the driving chip on the control circuit board 100. At the same time, this layout mode is also convenient for installing a larger heat sink 200, further increases the heat exchange area of the heat sink 200 without significantly increasing the area of the drive, and improves the heat dissipation efficiency, thereby improving the working stability of the frequency converter, and being suitable for three-phase frequency converters with higher power.

[0033] With reference to Figure 8 In the embodiment, the devices on the control circuit board 100 are arranged on the side of the control circuit board 100 away from the heat dissipation circuit board 500, so as to further avoid the heat generated by the discrete power device 300 from being transferred to the devices on the control circuit board 100. The heat dissipation circuit board 500 is preferably made of an aluminum substrate with better heat conduction performance, so as to further improve the efficiency of transferring the heat generated by the discrete power device 300 to the heat sink 200, and resist high temperature without softening due to high temperature generated by the discrete power device 300 during operation. A heat dissipation silicone coating is arranged between the heat dissipation circuit board 500 and the end surface of the heat sink 200, so as to further improve the efficiency of transferring the heat generated by the discrete power device 300 to the heat sink 200.

[0034] With reference to Figure 7 and Figure 8In the embodiment, the heat dissipation circuit board 500 is detachably mounted on the end face of the heat sink 200 by screws, so as to facilitate maintenance. The heat dissipation circuit board 500 is provided with screw holes for passing through the screws, and the control circuit board 100 is provided with mounting avoiding holes 110 arranged directly above the screw holes, so as to facilitate the screwdriver to pass through the mounting avoiding holes 110 to dismount the screws on the heat dissipation circuit board 500.

[0035] It should be noted that, in the description of the utility model, if the orientation description is involved, for example, the orientation or position relationship indicated by the upper, lower, front, rear, left, right and the like, the orientation or position relationship shown in the drawings is based on, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or element must have a specific orientation, be constructed or operated in a specific orientation, and cannot be understood as a limitation on the utility model.

[0036] In the description of the utility model, the meaning of several is one or more, the meaning of multiple is two and more than two, greater than, less than, more than and the like are not included in the number, above, below, within and the like are included in the number. If the first or second and the like are described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0037] In the description of the utility model, unless otherwise explicitly limited, the words such as setting, mounting and connecting should be understood in a broad sense, and the person skilled in the art can reasonably determine the specific meaning of the above words in the utility model according to the specific content of the technical scheme.

[0038] The above-mentioned embodiments are only preferred embodiments of the utility model, and cannot be used to limit the scope of protection of the utility model. Any non-essential change and replacement made by the person skilled in the art on the basis of the utility model belongs to the scope of protection required by the utility model.

Claims

1. A variable frequency drive, comprising a control circuit board (100), a heat sink (200) and at least one set of discrete power devices (300), the control circuit board (100) being provided with a rectifier circuit, a controller and at least one driving chip, the discrete power devices (300) of the same set forming an inverter circuit, an input end of the rectifier circuit being electrically connected with an external power supply, an input end of the inverter circuit being electrically connected with an output end of the rectifier circuit, an output end of the inverter circuit being connected with a load, an output end of the driving chip being electrically connected with a control end of the discrete power device (300) in the corresponding inverter circuit respectively, the driving chip being electrically connected with the controller and being controlled by the controller, characterized in that, The discrete power device (300) is fixedly installed on the heat sink (200), and the control circuit board (100) is provided with pads for welding with pins of the discrete power device (300), and the discrete power device (300) is electrically connected with the control circuit board (100) by welding the pins with the pads.

2. The variable frequency drive of claim 1, wherein, The discrete power device (300) is detachably installed on the heat sink (200) by screws.

3. The variable frequency drive of claim 1, wherein, Further comprising a housing (400) provided with a mounting portion (410) for mounting the heat sink (200), and the control circuit board (100) is fixedly arranged on one side of the mounting portion (410), and the mounting portion (410) is provided with a window for exposing an end surface of the heat sink (200), and the discrete power device (300) is fixedly installed on the end surface of the heat sink (200) through the window.

4. The variable frequency drive of claim 1, wherein, Further comprising a heat dissipation circuit board (500), and the discrete power device (300) is attached to a first surface of the heat dissipation circuit board (500), and the first surface of the heat dissipation circuit board (500) is provided with a plurality of pin connectors (510), and the pin connectors (510) are electrically connected with the corresponding discrete power devices (300), and the control circuit board (100) is arranged on one side of the first surface of the heat dissipation circuit board (500), and the control circuit board (100) has a gap with the heat dissipation circuit board (500), and the pin connectors (510) are welded with the pads, and a second surface of the heat dissipation circuit board (500) is connected with the heat sink (200).

5. The variable frequency drive of claim 4, wherein, The heat dissipation circuit board (500) is an aluminum substrate.

6. The variable frequency drive of claim 4, wherein, A heat dissipation silicone coating is arranged between the heat dissipation circuit board (500) and the end surface of the heat sink (200).

7. The variable frequency drive of claim 4, wherein, The heat dissipation circuit board (500) is detachably installed on the end surface of the heat sink (200) by screws, and the control circuit board (100) is provided with a plurality of mounting avoiding holes (110), and the plurality of mounting avoiding holes (110) are one-to-one correspondingly arranged above screw holes on the heat dissipation circuit board (500).

8. The variable frequency drive of any of claims 1-7, wherein, A plurality of heat dissipation grid plates (210) are vertically arranged on a side of the heat sink (200) away from the discrete power device (300).

9. The variable frequency drive of claim 8, wherein, Surfaces of the heat dissipation grid plates (210) are wavy.

10. The variable frequency drive of any one of claims 1 to 7, wherein, The rectifier circuit comprises a rectifier bridge and a DC bus capacitor, an input end of the rectifier bridge is electrically connected with external power supply, an output end of the rectifier bridge is electrically connected with an input end of the inverter circuit, and the DC bus capacitor is connected in parallel with the output end of the rectifier bridge, and the rectifier bridge is a single-phase rectifier bridge or a three-phase rectifier bridge.

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