Monitoring Tools For Frequency Conversion Air-condition Control System

Since frequency conversion technique has developed quite rapidly and has some outstanding virtues, it become more and more widely used in the home electronic appliances. And the frequency conversion air condition is a typical case.Frequency conversion air condition is a kind of air conditions which is based on the frequency conversion compressor and intangible control method. The work principle is almost like this: By controlling the power supply output voltage frequency, we can regulate the rotation speed of the compressor to change the volume continuously, and then indirectly control the refrigerating output. The rotation speed is changing proportionally to the indoor load power of the air condition. When the order is to change the indoor temperature rapidly, the indoor load power is becoming larger; meanwhile, the compressor rotation speed is accelerated by the micro-controller. And when the load power is dropping down it works in the opposite way. Therefore, no matter in different seasons or in the day or night, the air condition can make the room comfortable with the low energy consuming and it also does less harm to the environment. There are also some other virtues, like low-noise,long using time,etc. The tests show that, compared to the fixed frequency air conditions, the conversion one has 5-6 dB lower noise and 5-8 years more using time, it has a good potential and will lead the trend in the market.The compressor's conversion frequency control part is the most important part in the air condition system. In the R&D process, the hardware is often broken down. Many reasons may cause this problem, such as the irrational algorithm,the lack protection of the hardware circuit and software,the burst changing of the load current and something like that. In this situation, we hope to get a safer develop platform which can provide the engineer real-time parameters and help us to monitor the running status. It should have a higher security level by making the immediate protection when the fault happens and it can help the engineer to solve problem,analyze the bugs and provide a visible develop process to make developing become more efficient and short the developing time cycle. Therefore, designing a develop and monitor platform like this is very urgent and necessary. And this paper is about this area.The main content of this paper is to introduce a develop system used in the debugging and developing of the conversion frequency controller. The function of the system includes setting the parameter on line,controlling the running status and monitoring the physical quantity outside. In the beginning chapters we are focusing on the introduction of the VF compressor controlling principle, discuss about the necessity and importance of this developing platform. We give an explanation about how to collect the current and voltage signals while the compressor is running. The following part is about the main work we have done in the developing, includes: assistant control system and real-time monitor system. Basically, the paper has respectively introduced the hardware circuit design section,the hypogenous firmware design section and the upper controller program design section. Among the introduction we mainly present the way we use the analogue SCI bus,CAN bus and USB bus communication to accomplish the set of the VF controller and the collection and display of the system parameter.The core of the hardware system is the slap-up sixteen bit microcontroller of the Microchip Corp. This chip microcomputer has all the inherent advantages which PIC18 Series have, like the low price and excellent computing capability; in addition, it has better persistence and an enhanced program flash memory. So it can fit all the design requirements.The system applies the inside integration PIC18F258 CAN communication controller, the CAN module executes the BOSCH standard CAN 2.0A/B protocol and supports the standard and extended data frame, the length of the dada is zero to eight byte, the programmable bit rates reaches up to 1Mb/s and supports the remote data frame. Peripheral circuits cooperate with the CAN bus driver chip 82C250 to accomplish the CAN communication to the compressor VF controller. This simplifies the system structure and enhances the reliability. We use the Philips PDIUSBD12 USB Port Chip to communicate with the superior computer, the protocol is USB1.1.The paper also specifies the SCI bus protocol, the specialty of the CAN communication module, USB-CAN communication port principle and hardware circuit. Meanwhile, it has analyzed the main structure of the main controller program.The superior computer software is a friendly human-machine interface. Users can set the parameter and debug the running system conveniently. It also has the function to display an oscillogram, gives a more vivid test result. We have used two types of dummy instruments (NI Lab Windows/CVI and Measurement Studio for VC++) to develop the superior computer software interface. The paper gives a detailed statement about software part (From the program method to the software functions).In the end of the paper, we demonstrate the application situation of our develop-used platform and confirm that our platform acts an important role in the frequency conversion controller developing process.