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• Power and Energy Systems

Preview ECE 469

This course supplements analysis tools presented in ECE 464 with practical design and measurement experience.

Power measurements and design:

• semiconductor measurements and driver circuits
• passive components
• magnetics

dc-dc converters and applications:

• non-isolated converters
• multi-quadrant converters
• isolated converters
• dc motor drives
• high-performance power supplies

ac-dc converters and applications:

• one-phase and three-phase converters
• batteries and chargers

dc-ac converters and applications:

• simple inverters
• pulse-width modulations
• ac motor drives
• switching amplifiers
• photovoltaic and renewable energy applications
• vehicle systems

Converter design project

This course supplements analysis tools and design practices presented in ECE 464 with practical design, measurement, and applications experience.

Topics:

Power measurements and design:

• semiconductor measurements and driver circuits
• passive components
• magnetics

dc-dc converters and applications:

• non-isolated converters
• multi-quadrant converters
• isolated converters
• dc motor drives
• high-performance power supplies

ac-dc converters and applications:

• one-phase and three-phase converters
• batteries and chargers

dc-ac converters and applications:

• simple inverters
• pulse-width modulations
• ac motor drives
• switching amplifiers
• photovoltaic and renewable energy applications
• vehicle systems

Converter design project

Circuit simulation project. Computer-based instrumentation is also used.

Each student prepares approximately five comprehensive technical reports, and each student is required to maintain a formal engineering notebook.

In addition to the lab topics, student groups design a working switching power converter, for a power supply or alternative energy application. Digital oscilloscopes, Hall-effect current probes, a power curve tracer, and power FETs are used, among many items. Additional application topics include switchign audio amplifiers, solid-state lighting, and magnetics design.

A "blue box" concept has been employed for dedicated lab equipment. Low-level function units that can be understood prior to application are used for energy conversion experiments. later in the course, these units are put away and students build discrete circuits for the same functions. All equipment and written lab materials have been made available as open-source material for any educational institution.

Introductory electronic circuits laboratory study.

P.T. Krein, ECE 469 Laboratory Manual.

R.S. Balog, Z. Sorchini, J.W. Kimball, P.L. Chapman, P.T. Krein, "Modern laboratory based education for power electronics and electric machines," IEEE Transactions on Power Systems, vol. 20, pp. 538-547, May 2005.

R. S. Balog, Z. Sorchini, J. W. Kimball, P. L. Chapman, P. T. Krein, and P. W. Sauer, "Blue-box approach to power electronics and machines educational laboratories," in Proceedings, IEEE Power Engineering Society General Meeting, 2005, pp. 962-970.

R. Balog and P. T. Krein, "A Modular Power Electronics Instructional Laboratory," in Record, IEEE Power Electronics Specialist Conference, 2003, vol. 2, pp. 932-937.

Engineering design, 1 credit hour.

Electronic power conversion is vital in modern electrical energy systems and devices. The primary goal of the course is to give students an in-depth laboratory experience in the design, operation, characterization, and application of electronic circuits for conversion and control of electrical energy. These circuits are essential elements of alternative and renewable energy systems, efficient electrical devices, and anything that requires a power supply. Important energy devices such as batteries and passive storage elements, motors, and others are presented. Applications to batteries, electric and hybrid vehicles, solar and wind power, and energy control are presented. The course has substantial design content, and a design project is included for the final portion of the semester. An additional goal is to give students practice in engineering notebooks and technical reports. The course supplements ECE 464, Power Electronics, which should be taken concurrently or as a prerequisite. The letter codes refer to the Department-wide program outcomes list.

The course emphasizes laboratory experience and applications breadth for electronic power conversion. In addition, students are expected to prepare professiona engineering project reports on their work. Breadth is emphasized by exploring all major power conversion families, multiple applications for each family, and key associated support topics. Depth is supported by digging in to device behavior. For instance, this course presents electrical characteristics and models for batteries, solar cells, and other devices. It explores design of magnetic devices. It considers how real components such as capacitors, inductors, and resistors deviate from ideal devices behavior and develops models and measurements to support designs. It explores static and dynamic losses of power semiconductors. It establishes how wire inductance and stray coupling will affect performance and how to consider these effects in design. Professionalism is addressed both by the breadth of the application space and by expectations for proper engineering notebooks and technical report preparation. Students submit a small number of comprehensive engineering reports, each addressing a topical area rather than a single self-contained lab experiment. A design project conducted over the final four weeks of the term allows students to explore an application and conversion circuit in depth. Students work in teams and are expected to rotate leadership assignments. A technical presentation of each design project is given to the full group at the end of the term. These aspects support educational objectives for professionalism and the learning environment.

A. By the completion of the first set of experiments (after about four weeks), the students should be able to do the following:

1. Perform a variety of static and dynamic measurements of a power electronic circuit, including current and voltage waveforms, average measurements of voltage, current, and power, and RMS measures of voltage and current. (1, 6, 7)

2. Explain issues of measurement error as they apply to power converters. (1, 6, 7)

3. List the purposes of a formal engineering notebook, and maintain a high-quality experimental record in a notebook. (3, 4, 7)

4. Demonstrate effective teamwork both in planning and in carrying out experimental activities. (5)

5. Build and test uncontrolled (diode) and controlled rectifier circuits, with resistive, inductive, capacitive, or battery loads. Single-phase and three-phase rectifiers should be familiar. (1, 2, 6)

6. Explain gate control techniques for thyristors, and write mathematical expressions for average converter output as a function of gate delay angle or time. (1, 3)

7. Discuss the electrical properties of rechargeable lead-acid, nickel-based, and lithium-ion batteries. (1, 3, 4)

8. Prepare a comprehensive engineering report that presents and analyzes laboratory work. (3, 6)

B. By the completion of the second set of experiments (after about six weeks), the students should be able to do all of the items listed under A, plus the following:

9. Build and test dc-dc converter circuits of one- and two-quadrant types. (6)

10. Predict the operation of general two-switch dc-dc converters, based on duty ratio and switching frequency. (1)

11. Discuss the significance of interface elements, such as bypass capacitors. (1, 2)

12. Analyze and discuss major applications of dc-dc converters, including regenerative converters and those for solar power. (1, 3, 4)

C. By the completion of the third set of experiments (after about 9 weeks), students should be able to do all of the items listed under A and B, plus the following:

13. Build and test quasi-square wave voltage-sourced inverters (VSI) and pulse-width modulated (VSI) inverters. (2, 6)

14. Discuss the characteristics of VSI and PWM methods, and compare them for specified applications. (1, 3)

15. Describe the fundamental operating requirements of ac motor drive systems, and explain the types of waveforms expected under a range of operating conditions. (1, 3, 4)

16. Discuss applications of inverters, including alternative energy systems and uninterruptible power supplies. (1, 3, 4)

D. By the completion of the fourth set of experiments (after about 11 weeks), the students should be able to do all of the items listed under A, B, and C, plus the following:

17. Discuss appropriate circuit models for real capacitors and inductors. (1)

18. Perform measurements to determine circuit parameters for C and L models. (6)

19. Perform measurements of hysteresis characteristics for small magnetic cores. (6)

20. Give comparisons among major types and materials for real capacitors and inductors. (1, 3, 4, 6, 7)

21. Explain the significance of saturation, wire size, and other factors as they affect the design and operation of inductors and transformers. (1, 3, 4, 6, 7)

E. By the completion of the course, the students should be able to do all of the items listed under A through D, plus the following:

1. Work in a team to design, build, and operate a dc-dc converter to meet a set of output ripple, output power, and input regulation specifications. The design should account for static device characteristics. (1, 2, 4, 5)

2. Discuss the effects of capacitor ESR and semiconductor device parasitics on the speed and operation of a power conversion circuit. (3, 6)

3. Design, build, and operate at least one type of gate drive circuit for a semiconductor. (1, 2, 6)

4. Discuss likely applications of a given dc-dc converter design. (1, 3, 4)

5. Identify improvements, enhancements, and additional measurements that would reduce a laboratory design to practice. (2, 4, 6, 7)

6. Present a cohesive and detailed engineering report about a laboratory design project. (1, 2, 3, 4, 6, 7)