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This paper deals with flatness-based control of a salient permanent-magnet synchronous motor in the bond graph (BG) domain. It develops two main points. The first proposes and develops a new flat outputs identification procedure valid for multiple-input non-linear BG models without elements in derivative causality assignment. This procedure exploits a variational (tangent) BG model obtained by using Kähler differentials. The second deals with control design based on physical system decomposition into electrical, mechanical, and coupling submodels. Each loop of the decomposition tracks a reference for the local flat output of the corresponding subsystem. This decomposition enables the designing of a control block for each submodel by means of system inversion using the concept of bicausality. Then, the resulting blocks are concatenated in order to build the global controller. Finally, the global stability of the feedback system for both cases (known and unknown load torques) is tested and the control scheme is assessed through simulations in order to illustrate the performances of the method.

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A bond graph (BG) based methodology for non-linear control system synthesis is presented through its application to a speed-tracking problem stated on a series direct current motor. After a global flatness analysis of the motor BG model, a two-loop cascade control structure is decided and developed on the basis of a physical system decomposition in electrical, mechanical, and coupling submodels. Each loop of the cascade tracks a reference for a flat output that is local to a subsystem of the decomposition. Bond graph techniques are given for the three main components of the design methodology: system decomposition, flatness analysis, and tracking controller design. Theoretical and practical properties of the resulting control system are discussed, and its performance is demonstrated through simulation experiments. The methodology is applicable to the broader class of non-linear BG models where input-output system inversion is well defined.

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This paper presents a method for controller synthesis in the bond graph domain. A dynamic feedback linearization and decoupling controller of rotor speed and rotor-flux amplitude of a current-fed induction motor is derived on the basis of a flatness analysis entirely conducted on a two-input nonlinear bond graph model of the motor. Once the rotor speed has been found as the first flat output, a technique which uses a variational bond graph and its associated quotient bond graph (modulo the differential of the first flat output) allows identifying the second flat output as being the angle of the rotor flux-linkage space vector. The flat output parameterization of the control outputs is later used to derive the control law. Simulation results are given to demonstrate the control system performance.

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