Choose Blocks to Model Motors or Actuators

Simscape™ Electrical™ includes several blocks that can model the same type of motor or actuator. For example, you can use the Motor & Drive (System Level), PMSM, or FEM-Parameterized PMSM blocks to model a permanent magnet synchronous motor (PMSM). You must choose a block that has sufficient modeling detail for the engineering design questions that you need to answer. It is also important not to use more detail than you need, because higher-fidelity models slow down simulation and are more complex to parameterize. The right block to use therefore depends on the level of complexity that you need to meet your design goals. To choose a block with the correct level of complexity, you:

Determine the level of fidelity that you need.
Determine the motor characteristics that you need to represent for your type of motor.
Select a block that can model a motor with those characteristics at that level of fidelity.
Parameterize the block.

Determine the Fidelity Level

You can typically choose between three blocks that can model the same type of motor, but implement mathematical models with different levels of complexity. Choose the simplest model that gives you enough detail to meet your design goals.

Level 1 models use energy balancing or other modeling abstraction methods. With energy balancing, when the block operates as a motor, the input electrical power equals the output mechanical power plus losses. When the block operates as generator, the input mechanical power equals the output electrical power plus losses. You can obtain realistic motor drive losses for a Level 1 model from tabulated loss data from a Level 3 model by using the generateMotorDriveROM function. For some actuation systems, such as piezoelectric traveling wave actuators, you can use a more abstract model that removes cyclic variables. For Level 1 models, you often need to draw the component modeling boundary around the drive electronics, control, and motor so that you do not need to model high-frequency current modulation, which requires a small simulation step size. Use Level 1 models when you need a long simulation time, for example, to analyze drive cycles for electric vehicles.
Level 2 models use fixed or parameter-dependent coefficients with a simple equivalent circuit. The fixed coefficients are usually fixed inductance values, such as the Ld and Lq coefficients of a PMSM. For a PMSM, the simple equivalent circuit corresponds to Ld, Lq, and the back EMF terms appearing in the Park’s transformed equations of the stator windings and rotor magnetic field terms. Use Level 2 models to design controls or systems in actuation applications, such as robotics and mechatronics, and for efficiency predictions when saturation and harmonics only weakly impact losses.
Level 3 models define motor behavior in terms of flux linkage. You can parameterize the model using data from a motor design tool that uses finite element (FE) analysis to derive flux linkage as a function of the stator winding currents and rotor angle. You must also incorporate iron loss information from the FE tool to make good loss predictions at high motor speeds. Use level 3 models when you need a high level of modeling detail, such as when you need to predict efficiency for traction applications or to capture torque and electrical current harmonics.

Determine the Characteristics to Model

After you determine the level of fidelity that you need, you must determine the characteristics of the type of motor that you need to represent in your model. One important motor characteristic is synchronicity. A motor can be:

Synchronous or no-slip — The rotor stays synchronized with the stator magnetic field.
Asynchronous — The rotor is not synchronized with the stator magnetic field and slips.

Another important motor characteristic is the rotor type. The rotor types that you can model in Simscape Electrical are:

Permanent magnet rotor — The rotor has permanent magnets that create its magnetic field.
Wound rotor — Electromagnets powered by slip rings or a brushless exciter create the magnetic field.
Permanent magnet and wound rotor — The rotor has permanent magnets that are augmented or modulated by an electromagnet powered by slip rings.
Squirrel cage rotor — The rotor has the form of parallel bars, which carry induced currents when cutting through the stator electromagnetic field.

You can define the flux distribution as:

Sinusoidal — The flux distribution you can see at a stator winding from the rotating rotor has a sinusoidal form. This flux distribution means that the back EMF induced in each of the stator windings also has a sinusoidal form reducing undesirable high-frequency mechanical and electrical current harmonics.
Trapezoidal — The flux distribution you can see at a stator winding from the rotating rotor has a trapezoidal form. This flux distribution means that the back EMF induced in each of the stator windings is approximately constant allowing you to use simpler and cheaper control strategies.

Choose the Right Block for the Model

These tables show the blocks that you can use to represent motors with different characteristics at each level of fidelity. The tables also show some common motors that have those characteristics. Use these tables to select the right block to model your motor or actuator.

Brushless Motors

Characteristics	Types of Motor	Blocks
Characteristics	Types of Motor	Level 1	Level 2	Level 3
Synchronous Permanent magnet rotor Sinusoidal Rotary	Interior permanent magnet (IPM) motor or interior permanent magnet synchronous machine (IPMSM) Surface permanent magnet (SPM) motor or surface permanent magnet synchronous machine (SPMSM) Transverse flux motor Axial flux motor PMSM servomotor	Motor & Drive (System Level) — Use this block only if your drive has closed-loop torque control.	PMSM PMSM (DQ0) PMSM (Single-Phase) PMSM (Four-Phase) PMSM (Five-Phase) PMSM (Six-Phase) To build faulted motor models, you also need these blocks: Magnetic Rotor Rotating Air Gap For information about modeling faults, see Faulted PMSM.	FEM-Parameterized PMSM
Synchronous Permanent magnet rotor Trapezoidal Rotary	Brushless DC (BLDC) motor BLDC servomotor	Motor & Drive (System Level) — Use this block only if your drive has closed-loop torque control.	BLDC	FEM-Parameterized PMSM
Synchronous Permanent magnet rotor Sinusoidal Linear	Permanent magnet linear synchronous motor (PMLSM) Linear synchronous motor (LSM) Direct drive linear motor	Motor & Drive (System Level) and Wheel and Axle — Use these block only if your drive has closed-loop torque control.	PMLSM	FEM-Parameterized PMSM and Wheel and Axle
Synchronous Permanent magnet and wound rotor Sinusoidal Rotary	Hybrid PMSM	Motor & Drive (System Level) — Use this block only if your drive has closed-loop torque control.	Hybrid Excitation PMSM PMSM	FEM-Parameterized Synchronous Machine
Synchronous Wound rotor Sinusoidal Rotary	Switched reluctance motor (SRM) Synchronous motor Synchronous machine Synchronous generator	Motor & Drive (System Level) — Use this block only if your drive has closed-loop torque control.	Simplified Synchronous Machine Synchronous Reluctance Machine Switched Reluctance Machine Switched Reluctance Machine (Multi-Phase) Synchronous Machine Model 1.0 Synchronous Machine Model 2.1 Synchronous Machine Round Rotor Synchronous Machine Salient Pole Synchronous Machine (Six-Phase) Synchronous Machine GENTPJ	FEM-Parameterized Synchronous Machine (for three-phase motors only) FEM-Parameterized Rotary Actuator (for reluctance machines) For more information about reluctance machines, see Switched Reluctance Motor Parameterized with FEM Data.
Asynchronous Wound rotor Sinusoidal Rotary	Wound rotor induction motor Asynchronous motor	Motor & Drive (System Level) — Use this block only if your drive has closed-loop torque control. Simplified Induction Motor — Use this block only if you have a constant frequency AC supply.	Induction Machine Wound Rotor Induction Machine (Single-Phase)	FEM-Parameterized Induction Machine (Wound Rotor)
Asynchronous Squirrel cage rotor Sinusoidal Rotary	Squirrel cage induction motor Asynchronous motor	Motor & Drive (System Level) — Use this block only if your drive has closed-loop torque control. Simplified Induction Motor — Use this block only if you have a constant frequency AC supply.	Induction Machine Squirrel Cage	FEM-Parameterized Induction Machine (Squirrel Cage)

Mechatronic Actuators

Characteristics	Types of Motor	Blocks
Characteristics	Types of Motor	Level 1	Level 2	Level 3
Rotary Stepping	Stepper motor Unipolar stepper motor	Stepper Motor with the Simulation mode parameter set to `Averaged` Unipolar Stepper Motor with the Simulation mode parameter set to `Averaged`	Stepper Motor with the Simulation mode parameter set to `Stepping` Unipolar Stepper Motorwith the Simulation mode parameter set to `Stepping`	FEM-Parameterized Rotary Actuator (electromagnetic devices only)
Rotary limited travel Non-stepping	Torque motor Torque actuator	Generic Rotary Actuator	Not supported	Not supported
Rotary Non-stepping	Piezoelectric rotary motor Travelling wave motor	Piezo Rotary Actuator	Not supported	Not supported
Linear limited travel Non-stepping	Solenoid Piezo stack Piezo bender	Generic Linear Actuator	Solenoid Piezo Stack Piezo Bender	FEM-Parameterized Linear Actuator (electromagnetic devices only)
Linear Non-stepping	Piezoelectric linear motor Travelling wave motor Piezo linear actuator	Piezo Linear Actuator	Not supported	Not supported

Brushed Motors

Characteristics	Types of Motor	Blocks
Characteristics	Types of Motor	Level 1	Level 2	Level 3
Permanent magnet DC supply	DC motor	Motor & Drive (System Level) — Use this block only if your drive has closed-loop torque control.	DC Motor	Not supported
No magnet DC supply	Shunt motor Compound motor	Motor & Drive (System Level) — Use this block only if your drive has closed-loop torque control.	Shunt Motor Compound Motor	Not supported
No magnet AC or DC supply	Universal motor Series wound motor	Motor & Drive (System Level) — Use this block only if your drive has closed-loop torque control.	Universal Motor	Not supported
Permanent magnet DC supply Controlled	RC servomotor	Not supported	RC Servo	Not supported

Parameterize the Block

After you select the right block, you must parameterize it. Datasheets from manufacturers are a good source for Level 1 and Level 2 models.

You can transform a Level 3 model into an equivalent Level 1 model that is easier to interpret and runs faster using the generateMotorDriveROM function.

You can pre-parameterize some blocks, for Level 1 or Level 2 models, using the Block Parameterization Manager. These parameter values represent components by specific suppliers and match the manufacturer datasheets. For more information about using pre-parameterized parts, the blocks that support this option, the manufactured components that you can model, and additional parameterization options, see List of Pre-Parameterized Components.

You can parameterize Level 3 models using data from motor design tools that use FE analysis. These examples show how to parameterize these models using popular FE tools: