New Type Permanent Magnet Hydro Generation System:
A. Comparison of the traditional electro-magnetic hydro generation system and the new type permanent magnet hydro generation system:
1.Traditional Electro-Magnetic Hydro Generation System:
2.New Type Permanent Magnet Hydro Generation System:
Usually for hydro generation, the generator needs to connect to the national grid. And the generator has to work at synchronous speed (usually 3000rpm, 1500rpm, 1000rpm or 750rpm) to output 50Hz which the national grid requires. So in traditional hydro generation system, there is a gearbox between the turbine and the generator. The gearbox increases the speed to synchronous speed. And the generator is connected to the national grid by the grid connected device. The gearbox efficiency is not high and it is wearing parts, so the efficiency of the whole system is not high.
In new type of hydro generation system, the turbine can work at any speed, drive the permanent magnet generator directly. The converter will turn the power of non- 50Hz from the generator to the power of 50Hz. Do not need the gearbox and speed adjusting device. The water turbine does not need to work the synchronous speed. It can work at any optimum speed according to the water volume changing. So the system will work at optimum situation. The efficiency and the reliability is highly increased. The converter has MPPT (Maximum Power Point Tracking) function. So the system can use the water power and output the max power. The converter has grid-connected function, so do not need extra grid-connected device.
B. Introduction of some parts of the new type hydro generation system:
●There are permanent magnets in the PMG rotor. The magnets will provide the magnetic field to the generator. Do not need the excitation windings and excitation control system. Simplify the structure. The PMG can work at very low speed and very high speed and still has high efficiency. The PMG performance is very good for variable running system. Traditional electro-magnetic generators cannot do this point. PMG can increase 10% to 20% generating capacity.
●There is the converter in the system, so the turbine can works at any speed. The turbine does not have to work at synchronous speed. So do not need speed- stabilizing device anymore. When the water volume is small, the turbine can work at low speed. In this case the turbine can get the power from the water flow more adequately. When the water volume is big, the turbine can work at the speed higher than the rated speed, so the system can use more water power without wasting the water. The turbine always works at an optimum speed, so the system can generate 10% more than traditional hydro generation system.
●The 3-phase bridge converter will rectify AC to DC, and invert the DC to high frequency 3-phase chopping AC power. Then the power becomes sine-wave power by a LC filter, and connects to the grid finally. The converter has MPPT (Maximum Power Point Tracking) function and grid voltage automatic tracking function, which will make the system work at the optimum situation. The converter has RS485 communication which allows you to monitor the system and collect the data remotely. The converter is closed-loop controlled，has Anti-Island control function and other complete protection functions. When there is error in the system, the converter can protect the system in time.
