Research On Control & Saving Energy In Pump Which Is On Ship Taking Water Project

The distance of pumps in water factory is designed in the light of the lowest river level for the purpose of the best distance. At the same time,a lot of electrical energy is wasted when the level is high and the working curve is displaced. So urgent affairs are choosing right timing ways to rebuild the pumps. Applying frequency conversion timing to wind machines and pumps is an important technology in our country.The situation is not only changed with the water level but also the distance of pump machines. In order to ensure the working point being in high efficiency working area,the only way is to adjust correlative performance parameters. So far,most pump machines in ships are not taken action.When the level is high,pumps still work in high distance,which have the energy wasted. A method is to replace pump impeller to change the distance of pump. But it is effective only in small area and hard to manage.According to pump performance curve shown we can get that the distance H is changed with the rotate speed n in the same point Q,and the flux Q is changed with the rotate speed n in the same point H. From the curve we can get the rule that the distance and rotate speed are in direct with ratio at the same flux point,and the rotate speed and the flux are also in direct with ratio at the same distance point.When the pump machines pass the short distance pipeline,the water in trail pipeline goes to exoteric dyke. The variety of pressure is little and sometimes forms non-pressure status. When the pressure parameter changes little and can't reflect the change of level,it is impossible to get correct rotate speed instruction according to the pressure parameter.When the river's level is high,the purpose of saving energy can be realized by reducing the pump rotate speed and the output power of electric machines. At the same time,the water quantity can be ensured by setting up the relation of level,distance and flux.Water-level instrument transmits the level information to computer which gives the rotate speed instruction to control the motor by mathematic model. Then the speed of high-power water pump motor is adjusted by frequency conversion,which can decrease the plant wire surge of current and pipe net surge of hydraulic pressure when the motor suddenly started or stopped. Technology of frequency conversion can reduce consume,increase life of pipe net and equipment,which is very significance of economy and a way to ensure credibility of water supply.The 6KV transducer with the series-wound unit of the PWM pressure type can realize the output of the direct high pressure by collecting a lot of lower frequency conversion pressure. It is no use inputting the tune wave filter and the compensate instruments with the power factor because the little pollution of the tune wave and the lower power factor. At the same time,there are not many problems for the good wave shape,for example,yawp,outputting du/dt,torque impulse and so on.Technology of frequency conversion had developed into an absolute technology. Moreover,it is important in many fields,such as reasonable using resource of water,decreasing pollution of environment,saving electric sources,improving work condition,saving materials,reducing costs and improving output.