First solve for initial conditions failed to converge. Trying again with all high priorities relaxed to low.

Question

Pratik Shirude 2021-3-6

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回答： pravallika gandhaveeti 2024-8-2

Hi Guys,

I have made this powertrain for parallel hybrid configuration shown in picture below. when i run simulation i get get erros which are as follows

First solve for initial conditions failed to converge. Trying again with all high priorities relaxed to low.

Component:Simulink | Category:Model warning

Unable to satisfy all initial conditions. The variables involved are listed below. The following variables are involved in a constraint that conflicts with their targets: 'DC_Motor.w' (Angular velocity) 'Generic_Engine.engine_inertia.w' (Rotational velocity) Here are the equations involved: all components involved 'Mini_tractor_powertrain/DC Motor'Equation location is: 'E:\toolbox\physmod\elec\library\m\+ee\+electromech\+brushed\dc_motor.sscp' (no line number info) 'Mini_tractor_powertrain/Generic Engine'Equation location is: 'E:\toolbox\physmod\simscape\library\m\+foundation\+mechanical\+rotational\inertia.ssc' (line 45) 'Mini_tractor_powertrain/Simple Gear'Equation location is: 'E:\toolbox\physmod\sdl\sdl\+sdl\+gears\simple_gear.sscp' (no line number info)

Component:Simulink | Category:Model warning

An error occurred while running the simulation and the simulation was terminated

Caused by:

['Mini_tractor_powertrain/Subsystem1/Subsystem1/Solver Configuration']: Initial conditions solve failed to converge.
Nonlinear solver to advance time one step failed to converge due to Linear Algebra error. Failed to solve using iteration matrix.
The model may not give enough information to make it possible to solve for values of some of its variables. Specific advice is given below. all components and nodal across variables involvedTie variable 'DC_Motor.p.v' (Voltage) to a definite value, for example by connecting an appropriate domain reference block. Dependency found among topology equations. Check for missing reference node.

If anybody has solution for this please reply immediately

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Bruno Rodriguez Esteban 2021-3-8

Hi Pratik,

Without the model, it is a bit difficult to debug, but the message indicates:

The following variables are involved in a constraint that conflicts with their targets: 'DC_Motor.w' (Angular velocity) 'Generic_Engine.engine_inertia.w' (Rotational velocity)

This means that the initial value of the angular velocity of the "DC_Motor" and "Generic_Engine" are different. You might be inputing contradictory values. They need to be consistent, otherwise the solver will struggle.

Hope this helps.

Regards,

Bruno.

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Answer 1

Steve Miller 2021-3-14

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Hi Pratik Shirude - here are three ways to eliminate the warnings at the start of the simulation.

Remove the inertia from the Generic Engine block. On the "Dynamics" tab, set "Inertia" to "No Inertia".
Put a flexible shaft between the engine and the motor (parallel spring-damper between the engine and the gear)
Set the initial speed of the Generic Engine block to be exactly consistent with speed of the DC motor block, taking into account the gear ratio between the two blocks

The meaning of the diagnostic is as Bruno describes in his comment - you have specified two inconsistent initial shaft speeds in the Generic Engine and DC Motor block, and Simscape is trying to find a compromise between those two values. Since it is physically impossible to match both values, it is issuing a warning.

--Steve

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Answer 2

Syed Anass 2023-11-16

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'Output Port 1' of 'batteryModel2november/Constant' is not connected.

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