Dear more experienced colleaguesl,
I am a little bit confused about speed/power flow control of Vertical Axis Wind Turbine. I have started research on control of VAWT. My model was implemented in Matlab/Simulink software. It consists of wind turbine model (form simulink library), PMSG, controlled rectifier (based on IGBT modules) and connected load (paraller with filtering capacitor). I started my research with uncontrolled rectifier. I set "nominal" load value - which gives output power equal to nominal power of wind turbine (20 kW). Then I replaced uncontrolled rectifier with controlled rectifier. I've implemented also a control algorithm using dq transformation. Id* set to 0. In the second control loop I have Iq control. Before Iq controller there is placed controller of velocity of rotation, which gives at the output required value of torque. Next, this value of torque is recalculated to the value of required Iq currrent - according with torque equation.During change of load of rectifier I can see changes in value of parameters like output voltage of PMSG, speed etc. But changing the setpoint of velocity doesn't have an impact on the behaviour of whole system. Changing the parameters of controllers don't gives new results. Only change in load value gives visible changes in parameters recorded by he scopes. How important (in this situation) is the fact that output of PMSG is modelled as a currnet sources - not as a voltage sources. I am using all blocks form Simulink library..
To sum up. I think that change of rotation velocity should results in change of power supplied to the load , but my model "beahve " completely different ?
Where is mistake in my reasoning?
Thank you in advance for any suggestions and help.
which simulink model of the VAWT are you working with, because it is not logical that the wind speed variation doesnt have an effect on the power output, maybe if you upload a picture of your model i can have an idea about what's wrong with your model
Hello,
Thank you for answer.
That was my mistake in model implementation. but I still have few
questions. As I said ealier. My concept is to test power (speed) regulation for the resistive load.
I attach my model screen.
- I set a setpoint of the angular speed and using the control system I would like to
stabilize power delivered to the load (by speed regulation),
- I am using controlled rectifier - three phase IGBT bridge,
- Control system based PI controllers. I thought about using symetrical and modulus optimum for tunning current and spped controllers,
- My idea was to control power delivered to the laad. After conducting some tests I decided that 7,5 Ohms is enough to absorb full power - 20 kW. So I set the parameters of Wind Turbine Model to achieve 20 kW at the particular wind speed (this wind speed is an input to wind turbine model) and given angular speed. This velocity is set as a setpoint,
- Is it better to operate on normalized values (range: 0-1) or real values in control system path ?
- I also consider how important is the fact, that the output of the PMSG is modeled as a current sources. Could it affect on the final results? In real generator the output is voltage - not current.
I will be very thankful for any suggestions or steering me towards proper reasoning,
Now I have another mistake in my model, because turbine doesn't stabilize at setpoint velocity value, but after some time goes to oscilations around 0 position.
- Badges
- Science topic