scholarly journals Maximum torque control of an induction machine in the field weakening region

1995 ◽  
Vol 31 (4) ◽  
pp. 787-794 ◽  
Author(s):  
Sang-Hoon Kim ◽  
Seung-Ki Sul
Keyword(s):  
Induction Machine ◽  
Torque Control ◽  
Maximum Torque ◽  
Field Weakening

scholarly journals Optimal feedforward torque control for nonlinear induction machines considering stator & rotor copper losses and current & voltage limits

2021 ◽  
Author(s):  
Christoph Hackl ◽  
Andre Thommessen
Keyword(s):  
Induction Machine ◽  
Induction Machines ◽  
Optimal Operation ◽  
Torque Control ◽  
Lagrangian Formalism ◽  
Maximum Torque ◽  
Optimal Feed ◽  
Doubly Fed Induction Machine ◽  
Doubly Fed ◽  
Copper Losses

In order to analytically solve the optimal feed-<br>forward torque control (OFTC) problem of induction machines (IMs), the unified theory for synchronous machine introduced in [1] is extended by considering relevant IM nonlinearities and incorporating stator and rotor copper losses. Instead of the well known Maximum Torque per (stator) Current (MTPC) operation strategy, Maximum Torque per (copper) Losses (MTPL Cu ) is realized and extended by the Maximum (rotor) Current (MC r, ext ) strategy due to stator and rotor current limitations. Modeling magnetic saturation and cross-coupling effects leads to a con-<br>strained nonlinear optimization problem which is solved based on the idea of sequential quadratic programming (SQP). The second order Taylor approximations are formulated in implicit form as quadrics. Applying the Lagrangian formalism to the quadratic problem leads to analytical solution for the optimal rotor currents. For a doubly-fed induction machine (DFIM), a decision tree for optimal operation management is presented and the OFTC is validated in simulations for a real nonlinear IM.

scholarly journals Generic loss minimization for nonlinear synchronous machines by analytical computation of optimal reference currents considering copper and iron losses

2020 ◽  
Author(s):  
Christoph Hackl ◽  
Julian Kullick ◽  
Niklas Monzen
Keyword(s):  
Optimal Operation ◽  
Torque Control ◽  
Synchronous Machines ◽  
Unified Theory ◽  
Loss Minimization ◽  
Maximum Torque ◽  
Field Weakening ◽  
Iron Losses ◽  
Highly Nonlinear ◽  
Smooth Transitions

The unified theory (introduced in [1]), which allows<br>to analytically solve the optimal feedforward torque control<br>(OFTC) problem of anisotropic synchronous machines (SM),<br>is extended by considering all relevant machine nonlinearities<br>and copper and iron losses and, thus, minimizing the overall<br>(steady-state) losses in the machine. Instead of the well known maximum torque per current (MTPC) operation strategy, maximum torque per losses (MTPL) is realized. The unified theory for the derivation of the analytical solution is briefly recapitulated. Moreover, current and speed dependent iron losses, as well as, magnetic saturation and cross-coupling effects are considered. The resulting nonlinear optimization problem is solved via online linearization of the relevant expressions. The linearization is exemplified for flux linkages and machine torque. The presented decision tree guarantees an optimal operation management and smooth transitions between all operation strategies such as MTPL, field weakening (FW), maximum current (MC) and maximum torque per voltage (MTPV). Finally, the extended unified theory is validated for a real, highly nonlinear SM.

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