Induction Motor Drive Simulation

Simulink/Simscape Electrical models for two scalar speed-control schemes of the same three-phase squirrel-cage induction motor.

• Model A - V/f voltage-source drive (3φ diode bridge → LC pre-link → DC-DC boost converter regulating V_dc to 700 V → 3-leg IGBT VSI → asynchronous machine; open-loop scalar V/f law with low-frequency boost; 5 kHz SPWM carrier).
• Model B - CSI drive with slip regulation (α-controlled 3φ thyristor rectifier → DC-link choke → 6-IGBT/Diode current-source inverter → asynchronous machine; outer speed PI → constant-Iₘ map → inner I_dc PI; canonical Structure 1 from the EE4251 Electrical Drives lecture notes).

Team: Amarasuriya G.N. and Perera P.S.R.

Repository layout

induction-motor-drive-sim/
├── setup.m
├── params/motor_params.m
├── scripts/
│   ├── build_vf_model.m       Model A build (V/f VSI + DC boost)
│   ├── build_csi_model.m      Model B build (CSI + Structure 1)
│   ├── build_all_models.m     wrapper: builds all four .slx variants
│   ├── run_all_a_cases.m      Model A test runner (A1-A4) + THD
│   ├── run_all_b_cases.m      Model B test runner (B1-B3) + THD
│   ├── plot_comparison.m      A vs B overlay plots + joined table
│   ├── analyze_thd.m          FFT/THD per case
│   ├── sweep_boost.m          m_boost sweep on case A4
│   └── generate_tables.m      LaTeX-ready summary tables
├── docs/                      Model A.md, Model B.md
├── models/                    headless .slx (one per drive)
├── figures/
└── report/

Headless .slx files are tracked; the script-driven variants (vf_control_drive.slx, csi_current_control_drive.slx) are auto-regenerated by the runners. To regenerate them explicitly run build_all_models;.

Prerequisites

• MATLAB R2023a - R2024a
• Toolboxes: Simulink, Simscape, Simscape Electrical

How to build and run

The script-driven model is the source of truth; the headless companion is for fresh-MATLAB-session demos.

setup;                                 % addpath + assign p to base
build_all_models;                      % builds all four .slx variants

% Model A - V/f drive
out = sim('vf_control_drive');
summary_a = run_all_a_cases();         % A1-A4 + THD + figures
sweep_boost();                         % m_boost sweep on A4

% Model B - CSI drive
out = sim('csi_current_control_drive');
summary_b = run_all_b_cases();         % B1-B3 + THD + figures

% Comparison and bookkeeping
plot_comparison();                     % A↔B overlays + joined table
generate_tables();                     % LaTeX summary fragments

Regression tests

Regression tests are not shipped in the public repo. To verify a local clone matches an expected baseline, drop a baseline CSV at tests/expected_summary.csv (Model A) or tests/expected_summary_b.csv (Model B) and compare against a fresh run_all_a_cases() / run_all_b_cases() output - either via runtests('tests') after authoring a test class, or by diffing results/summary.csv against the baseline manually.

Headless variants run from a fresh MATLAB session without setup:

load_system('models/vf_control_drive_headless.slx');
out = sim('vf_control_drive_headless');
load_system('models/csi_current_control_drive_headless.slx');
out = sim('csi_current_control_drive_headless');

Motor parameters

Loaded by the Simulink Asynchronous Machine SI Units block via PresetModel = 15: 5.4 HP (4 kW) 400 V 50 Hz 1430 rpm. We do not hand-set R/L/J - they come from the preset's tabulated values for a reference 4 kW industrial motor.

parameter	value
Rated shaft power	4 kW
Line-to-line voltage	400 V (RMS)
Frequency	50 Hz
Poles	4
Rated rotor speed	1430 rpm (slip 4.67 %)
Rated load torque	26.71 N·m = 4000 / 149.75
Rs, Rr'	1.405 Ω, 1.395 Ω
Lls, Llr'	5.84 mH each
Lm	172.2 mH
J	0.0131 kg·m²

Model A - V/f voltage-source drive

Open-loop scalar V/f speed control fronted by a diode-bridge rectifier, LC pre-link, DC-DC boost converter regulating the inverter-side bus to 700 V, and a 3-leg IGBT VSI. The boost stage is required so linear SPWM at m = 1 delivers the motor's rated 400 V LL at the stator.

For the full Simulink layout, naming conventions, A1-A4 results and case-by-case observations see docs/Model A.md.

Model B - CSI drive with slip regulation

Closed-loop CSI drive following EE4251 Electrical Drives. The outer speed PI on (ω_r* − LPF(ω_r)) produces the slip-frequency reference ω_2*; the constant-Iₘ map (lecture notes Part 3, pp. 5-6) converts |ω_2| to the DC-link current command I_d* = (π/√6)·I_1*; the inner I_dc PI sets the rectifier firing angle α. The CSI fires at ω_1 = ω_2 + p·ω_r. The CSI bridge uses 6 × IGBT/Diode.

For the full Simulink layout, naming conventions and B1-B3 results see docs/Model B.md.

Test results

Both models verified end-to-end with their respective per-case runners. See report/main.pdf for full discussion; the headline steady-state numbers are:

Pair	rpm cmd	rpm ss A / B	T_e ss A / B (N·m)	i_a THD A / B (%)
A1 / B1	1500	1499 / 974	0.40 / −2.49	1.17 / 41.17
A2 / B2	1500	1440 / 1487	27.67 / 27.13	1.33 / 12.72
A3 / B3	1000	999 / 785	0.31 / −6.92	0.03 / 42.38

References

• EE4251 - Electrical Drives notes.
• Bose, 2002 - Modern Power Electronics and AC Drives, Prentice-Hall. Ch. 8 §8.2.1 (V/f law); Ch. 6 §§6.4-6.5 (thyristor-ASCI and IGBT-CSI topologies).
• Krishnan, 2001 - Electric Motor Drives: Modeling, Analysis, and Control, Prentice-Hall. §5.6 V/f cross-reference; §6.4 CSI cross-reference.
• Erickson & Maksimović, 2001 - Fundamentals of Power Electronics, 2nd ed., Springer. DC-DC boost topology and CCM PI control.
• Colak & Kabalci, 2010 - Review of multilevel voltage source inverter topologies and control schemes. PWM strategy background.

License

See LICENSE.