Abstract — Liquid Level Control In Coupled Two Tank System
intermediate flow. The nonlinear behavior is evident in the curved response patterns, especially during the initial filling phase. The PID controller was implemented to regulate tank levels by minimizing the error between desired and actual levels. The control law is: The PID controller processes the error signal (difference between desired and actual levels) to generate appropriate control actions. Through careful experimentation and analysis, I determined that the following parameter values provided good initial performance: proportional gain (Kp) of 2.5 to provide immediate response to level errors, integral gain (Ki) of 0.5 to eliminate steady-state offset, and derivative gain (Kd) of 0.3 to improve dynamic response and reduce overshoot.
Analytical & State-Space Control Methodology
Figure 2: Power Converter Circuit Schematic & Electrical Interfacing for Liquid Level Control In Coupled Two Tank System Figure 4 PID-Controlled System Response with Kp = 2.5, Ki = 0.5, Kd = 0.3 Chapter 2: Semiconductor Dynamics: MOSFET & IGBT Switching Characteristics & Losses This response plot reveals several important aspects of the system's behavior. The liquid levels (hI and hI) smoothly approach their setpoints of 1.5m and 1.0m respectively. The initial transient response shows well-controlled overshoot of approximately 5%, which I found to be a good compromise between speed and stability. The settling time of around 50 seconds indicates efficient convergence to the desired levels. Most importantly, the steady-state error is effectively eliminated, demonstrating the integral control's effectiveness.
Simulink Waveforms & Power Quality Findings
Figure 5: PID-Controlled System Response with Kp = 3, Ki = 0.8, Kd = 0.4 The aggressive parameter set (Kp = 3, Ki = 0.8, Kd = 0.4) revealed interesting trade-offs. The faster settling time of approximately 40 seconds comes at the cost of increased overshoot (7%). I observed that the higher proportional gain provides quicker initial response, while the increased integral gain ensures faster error correction. The higher derivative gain helps maintain stability despite the more aggressive control action.
Scope & Practical Applications
- High-efficiency DC-DC converters and isolated resonant topologies (LLC / DAB)
- Sinusoidal and Space Vector PWM inverters for grid integration & industrial motor drives
- MOSFET / IGBT gate driver optimization with active Miller-clamp shoot-through protection
- Power quality conditioning with Total Harmonic Distortion (THD) strictly compliant with IEEE 519
- Complete Simscape .SLX model files, parameter calculation scripts, and IEEE dissertation reports
Simscape Modeling
Simulink power stage & discrete PWM solver
Semiconductor Loss
SiC MOSFET & IGBT thermal dissipation
SVPWM Control
Vector control, FOC & digital PI loops
IEEE 519 Quality
FFT harmonic spectrum & THD < 5% verification
Gate Driver Protection
Isolated bootstrap & Miller clamp circuits
HIL Prototyping
Ready for dSPACE, OPAL-RT & TI C2000 DSP
Engineering Software & Simulation Toolchains
Modeled using industry-standard power electronics simulation platforms, discrete numerical solvers, and HIL testbeds.
| Software Platform | Analytical Function & Role | Simulation Tier |
|---|---|---|
| MATLAB R2024b | Small-signal state-space averaging, bode stability margins, LC filter design, FFT analysis | Analytical Core |
| Simulink / Simscape | Time-domain switching models, non-linear semiconductor models, discrete PI controllers | System Simulator |
| PLECS / PSIM | High-speed thermal loss estimation (conduction and switching Eon/Eoff), snubber design | Thermal & Losses |
| Altium Designer | High-voltage isolation layout, creepage/clearance, power loop parasitic inductance minimization | Hardware PCB |
| TI C2000 / dSPACE | Embedded C codegen from Simulink, high-resolution ePWM registers, Hardware-in-the-Loop test | HIL Deployment |
Power Conversion & Control Topology Workflow
Systematic integration from DC input energy source and high-frequency gate drive to digital control loops and load delivery.
Renewable Bus
MOSFET/IGBT Bridge
& SVPWM Loop
Filter Stage
& FFT Analyzer
Motor Load
Verified Simulink Block Diagrams & Converter Waveforms
Advantages of the Liquid Level Control In Coupled Two Tank System Project
Why this project delivers superior academic grades and provides high technical evaluation standing.
High-Fidelity Simscape Modeling
Provides precise numerical simulation of switching events using ODE variable-step solvers without numerical divergence.
Rigorous IEEE 519 Grid Compliance
Guarantees total harmonic distortion (THD) below 5% through optimized LCL filter attenuation and synchronous control loops.
Wide-Bandgap Semiconductor Sizing
Models modern SiC MOSFETs and GaN switches to achieve power conversion efficiencies exceeding 97.5% across full-load regimes.
Advanced Digital Modulation
Implements Space Vector PWM (SVPWM) and sinusoidal modulation maximizing DC-bus utilization by 15.5% over carrier methods.
Dynamic Small-Signal Stability
Custom MATLAB scripts compute control-to-output transfer functions Gvd(s), phase margins (> 50°), and gain margins.
Gate Driver Protection Mechanics
Incorporates active Miller clamps, negative turn-off bias, and isolated bootstrap circuitry to eliminate shoot-through faults.
Hardware-in-the-Loop (HIL) Ready
Directly exportable to embedded C for execution on Texas Instruments C2000 DSPs, dSPACE, and OPAL-RT real-time platforms.
Detailed Magnetic Core Sizing
Features rigorous inductor and high-frequency transformer calculations ensuring core saturation flux margins remain safe.
Direct Electric Vehicle & Grid Value
Builds technical competencies demanded by top automotive EV powertrain developers, solar EPCs, and power electronics consultancies.
Complete Turnkey Package
Delivered with full Simulink .SLX models, MATLAB initialization scripts, calculation sheets, IEEE-format report, and viva defense slides.
Sample MATLAB Code, Scope Waveforms & Harmonic Schedules
Representative excerpts illustrating the state-space analytical derivations, command solver output, and power quality distortion schedules.
[*] Compiling Simscape Electrical Switching Topology Engine... [✓] SiC MOSFET / GaN Switching Semiconductor Characteristics Loaded ──────────────────────────────────────────────────────────────────────── [OUTPUT REGULATION] Steady-State DC Voltage: 24.01 V (Ripple: 0.18 V p-p) [TRANSIENT STEP] 50% to 100% Load Recovery: 0.82 ms (Overshoot: < 1.4%) [SEMICONDUCTOR] Total Switching Loss (Psw): Psw = 4.82 W at 100 kHz [CONVERSION η] Full-Load Power Efficiency: η = 97.42% (Optimal Operating Band) ──────────────────────────────────────────────────────────────────────── [✓] Small-Signal Compensator Verified: Phase Margin = 54.8° (Robust Loop Stability)
[*] Simulating converter steady-state operating envelope across switching cycles...
| Electrical Parameter | Design Objective | Simulink Simulated Metric | Performance Variance | Status |
|---|---|---|---|---|
| Regulated Output Voltage | 24.00 V | 24.01 V | +0.04% | REGULATED |
| Inductor Current Ripple | < 25.0% | 18.4% | -26.4% | OPTIMAL |
| Voltage Peak Ripple | < 240 mV | 180 mV | -25.0% | OPTIMAL |
| Power Conversion Efficiency | > 95.0% | 97.42% | +2.42% | HIGH EFFICIENCY |
[✓] Power Quality Verification Complete: Injected harmonic components conform strictly to IEEE 519 standards.
Frequently Asked Questions
Project Deliverables & Support
Everything needed from project inception to final viva defense — delivered with expert technical support.
.SLX Files
.M Files
Schematics
Report
Slides
Recordings
Sheets
Q&A
Support
Extension