Browsing by Author "Giernacki, Wojciech"
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- CDM controller design of a grid connected photovoltaic systemPublication . Coelho, João Paulo; Giernacki, Wojciech; Gonçalves, José; Boaventura-Cunha, JoséDistributed power sources will become increasingly ubiquitous in the near future. In this power production paradigm, photovoltaic conversion systems will play a fundamental role due to the growing tendency of energy price, and an opposed trend for the photovoltaic panels. This will lead to increased pressure for the installation of this particular renewable energy source in home buildings. In particular, on-grid photovoltaic systems where the generated power can be injected directly to the main power grid. This strategy requires the use of DC-AC inverters whose output is synchronized, in phase, with the main grid voltage. In order to provide steady output in the presence of load disturbances, the inverter must work in closed-loop. This work presents a new way to design an inverter controller by resorting to the CDM design technique. The obtained results suggest that the controller achieved with this method, although simpler than other methods, leads to an acceptable and robust closed-loop response.
- CDM controller order and disturbance rejection abilityPublication . Coelho, João Paulo; Giernacki, Wojciech; Boaventura-Cunha, JoséThe coefficient diagram method is primarily an algebraic control design method whose objective is to easily obtain a good controller with minimum user effort. As a matter of fact, if a system model, in the form of linear differential equations, is known, the user only need to define a time-constant and the controller order. The later can be established regarding the expected disturbance type via a lookup table first published by Koksal and Hamamci in 2004. However an inaccuracy in this table was detected and pointed-out in the present work. Moreover the above mentioned table was expanded in order to enclose any k order type disturbance
- Experimental setup for turbocharger controlPublication . Coelho, João Paulo; Giernacki, Wojciech; Cunha, José Boaventura; Oliveira, Paulo de MouraThe way people travel is about to change. Since the early beginning of the twentieth century, two nowadays, the automobile has become the most prolific transportation form. The propulsion is done by an internal combustion engine which converter thermal energy, by burning diesel or petrol, into mechanical energy. However, due to several reasons reasons such as economical, envoronmental among others, there is a tendency to replace the i9nternal combustion engine by electrically powered motors. Electrical motors have many properties. One of them is its efficiency. An electric motor can easily reach an efficiency above 80% against to average 40% for internal combustion engines. Nevertheless, at the present, there are serious limitations regarding electric engine cars proliferation. There acquisition cost and autonomy are still two major restrictions. Even if the former aspect can be attenuated by proper tax reduction policies, the is strongly dependent of technical issues i.e. the development of faster methods, longer life batteries, etc.
- Robust CDM and pole placement PID based thrust controllers for multirotor motor-rotor simplified modelPublication . Giernacki, Wojciech; Horla, Dariusz; Sadalla, Talar; Coelho, João PauloPositioning and orientation precision of a multirotor aerial robot can be increased by using additional control loops for each of the driving units. As a result, one can eliminate lack of balance between true thrust forces. A control performance comparison of two proposed thrust controllers, namely robust controller designed with coefficient diagram method (CDM) and proportional, integral and derivative (PID) controller tuned with pole-placement law, is presented in the paper. The research has been conducted with respect to model/plant matching uncertainty and with the use of antiwindup compensators for a simple motor-rotor model approximated by first-order inertia plus delay. From the obtained simulation results one concludes that appropriate choice of AWC compensator improves tracking performance and increases robustness against parametric uncertainty.
- Rotational speed control of multirotor UAV's propulsion unit based on fractional-order PI controllerPublication . Giernacki, Wojciech; Sadalla, Talar; Gośliński, Jarosław; Kozierski, Piotr; Coelho, João Paulo; Sladić, SašaIn this paper the synthesis of a rotational speed closed-loop control system based on a fractional-order proportional-integral (FOPI) controller is presented. In particular, it is proposed the use of the SCoMR-FOPI procedure as the controller tuning method for an unmanned aerial vehicle’s propulsion unit. In this framework, both the Hermite-Biehler and Pontryagin theorems are used to predefine a stability region for the controller. Several simulations were conducted in order to try to answer the questions – is the FOPI controller good enough to be an alternative to more complex FOPID controllers? In what circumstances can it be advantageous over the ubiquitous PID? How robust this fractional-order controller is regarding the parametric uncertainty of considered propulsion unit model?