Variable frequency control device and variable frequency control method of variable frequency air-conditioner

Abstract

The invention relates to a variable frequency control device and a variable frequency control method of a variable frequency air-conditioner. The variable frequency control device of the variable frequency air-conditioner comprises a power transistor (1), wherein the power transistor (1) is connected with a control circuit of the variable frequency air-conditioner through a pin (5) and is also provided with a heat dissipation device, and the heat dissipation device comprises a heat exchanging element (3) contacting the power transistor (1); the power transistor (1) is an integral type transistor or a distributed type transistor; and the heat dissipation device also comprises a fan (4) arranged beside the heat exchanging element (3) and transmits air to the heat exchanging element (3). According to the actual heat yield and the heat environment of the variable frequency control device, the invention ensures the temperature of the power transistor (1) to be within a temperature range permitted by the work of the power transistor (1) by multiple ways, including the ways of enhancing the rotating speed of a heat exchanging air blower and enhancing the voltage and including the combination way of enhancing the rotating speed of a heat exchanging air blower and enhancing the voltage. The invention can prevent the temperature of the power transistor (1) positioned on a control circuit board of the variable frequency air-conditioner from exceeding preset temperature, reduces the power consumption of the fan by controlling the rotating speed of the fan and meets the requirement forthe heat dissipation of the power transistor (1) under bad working conditions.

Description

technical field [0001] The invention relates to a frequency conversion control device of a frequency conversion air conditioner and a control method thereof, belonging to the transformation technology of the frequency conversion control device of a frequency conversion air conditioner. Background technique [0002] With the increasing awareness of energy conservation and emission reduction in the society, inverter air conditioners have gradually become the choice of home and business users. However, unlike the traditional fixed-frequency air conditioner, the inverter air conditioner uses the inverter air conditioner control circuit board. During the operation of the inverter air conditioner control circuit board, heat is released from the power transistor. The capacity and heat dissipation are also significantly increased. [0003] When the heat released in the power transistor increases, the efficiency of the power transistor decreases and becomes unstable due to the incre...

AI Technical Summary

Problems solved by technology

However, unlike the traditional fixed-frequency air conditioner, the inverter air conditioner uses the inverter air conditioner control circuit board. During the operation of the inverter air conditioner control circuit board, heat is released from the power transistor. The capacity and heat dissipation are also significantly increased

[0003] When the heat released in the power transistor increases, the efficiency of the power transistor decreases and becomes unstable due to the increase of the surface temperature of the power transistor, and in some extreme cases, the power transistor itself burns out

In order to solve this problem, the conventional method is to install heat sinks on the power transistors to enhance heat dissipation, which can be used for small frequency conversion refrigeration devices, but for air conditioning systems, especially indoor cooling conditions of air conditioning systems in summer, due to the frequency conversion air conditioning control The circuit board is often installed on the side of the outdoor unit. It is at a relatively high temperature. Since most of the installation positions are in the pipeline side cavity of the outdoor unit, the cooling capacity of the heat sink installed in the harsh working conditions of high outdoor temperature It is still insufficient, and it is easy to cause the operating temperature of the power transistor to be too high

[0004] Another way, such as the structure disclosed in Japanese Patent Publication No. 9-236286, is to put the metal heat exchange part of the heat exchanger in the cavity on the fan side of the outdoor unit, and the frequency conversion control circuit board is still placed outdoors. The cavity on the side of the machine pipeline, through the rotation of the condensing fan that supplies air to the condenser, the airflow caused drives the outdoor air to pass through the metal heat exchange part of the heat exchanger, which can indeed strengthen the heat exchange of the heat exchanger; however, due to the layout The frequency conversion circuit board heat exchanger in the side chamber of the condenser can only be placed on the partition between the chambers. Since this position is close to the partition, the air volume is relatively small, which is more suitable for the occasion of small and medium radiators; the frequency conversion circuit board The heat exchanger is introduced into the condenser side, so that the outdoor air first passes through the frequency conversion circuit board heat exchanger to absorb heat, and the heated air then passes through the condenser, resulting in poor heat dissipation of the condenser and insufficient local heat dissipation, resulting in a condensation The unbalanced direct condensation capacity of the channel; many fans of the outdoor unit of the inverter air conditioner also adopt the frequency conversion technology, that is, the air volume adjusts the speed of the fan according to the difference between the set temperature and the indoor temperature, but the heat dissipation of the frequency conversion circuit board heat exchanger and the The cooling / heating capacity of the air conditioner is related, but it is also affected by other factors. For example, when the external power supply voltage becomes lower, the outdoor cooling fan will reduce the air volume, which will increase the condensation pressure and the heat dissipation of the frequency conversion will increase significantly. The rotating speed of the compressor and the fan of the outdoor unit may not be very high at this time, so that under this working condition, the heat exchanger of the frequency conversion circuit board cannot dissipate a large amount of waste heat, so that the performance of the power transistor deteriorates; due to the frequency conversion control The circuit board and the heat exchanger are located on both sides of the middle partition, so it is prone to air leakage, allowing outdoor air to enter the pipeline side of the outdoor unit, thereby polluting the circuit part of the inverter control circuit board and causing malfunctions

[0005] Even if the fan adopts a speed that matches the power supply, in extreme cases, the external temperature is high and the heat dissipation required is large, while the maximum operating temperature that the power transistor can withstand is relatively fixed, that is, when the heat dissipation required increases In the case where the difference between the tolerance temperature and the external temperature is decreasing, how to further improve the heat dissipation capacity in this case, so as to improve the working intensity that the equipment can adapt to, is still a problem to be solved

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