| With continue investments in new rural construction from our local government, our famers' living condition have changed dramatically. There are a lot of farmers have moved into commodity house from old one-floor building, some others even build their own new villa with multi-floors. However, due to some constraints, water supply equipment in most remote rural areas are obsolete and many of them could not get timely upgrade, the water pipes have serious aging problem and the leakage rate is very high. All things make the water pressure is unstable, which has been a key issue in water supply of countryside.Currently the most popular way to solve this issue is adding a booster pump in the pipe entrance of famer's house. The booster pump can provide a second time booster for water supply into various regions above the second floor. It is very convenient to our famers' daily life. Induction machines were widely used in booster pump to the driver the pump directly, but since the speed of induction machine is not adjustable the booster pump cannot make adjustment accordingly when the input water flow change. Besides of this it also has some other disadvantages such like:high noise level, low power efficiency, etc. These years with the development of new motor control technology and semiconductor, the inverter has been developed to control induction machine to achieve adjustable speed. In order to sense the inlet water pressure there is a water pressure installed in the pipe line so that the inverter can keep the output water pressure stable. However the water pressure sensor is susceptible to the ambient temperature, pipeline and other impurities, and long-term usage will deteriorate sensor's tolerance and reduce its measurement accuracy or even make failure. But the sensor needs periodic maintenance and calibration which reduces the reliability of the system. So this application is limited by plenty of conditions as we discussed before. In addition its system efficiency is still too low due to Induction machine being used.In order to solve these issues I designed a new constant head pump system based on permanent magnet synchronous motor (PMSM) in this paper. Thanks to PMSM motor, the system efficiency is higher, the motor size is smaller and with lower noise compare to Induction machine. And since there is no pressure sensor needed for constant head achievement, we can have better BOM cost and product's reliability will be improved remarkable. The long term benefit of this new pump system will be obvious. Besides of this the motor controller designed in this paper can work at wide voltage, which means this product can be sold to different countries around the world.The new algorithm for constant head without a sensor has been verified in pump testing system and the result shows the pump can work stable with head from 14.7meter to 15.3meter with input flow changing from Om3/h to 2.5m3/h. The performance test also show the system power consumption will reduce nearly 30% when we choose PMSM and the system noise level will also reduce 5db. This new product will improve famers' living standard remarkable and reduce the power consumption at the same time. So this product is worth to spread widely. |
PDF Full Text Request