Control system design Notes

Proportional Controllers not only save energy, they can give a controlled finish or treatment to a job. An on-off controller or thermostat limit protection has to be used in series, this is to to stop a Runaway Process.

control system design

There was a real life instance when a Temperature cycling oven maker (environment chamber), faced large liabilities as an 8086 based profile controller and chart recorder just locked up and all the electronic equipment were roasted. Here even a bimetallic thermostat would have saved the day. Nowadays we have a watchdog timer to prevent such uP mishaps, but still use an analog controller in series as an over temperature trip.

Other Reading

The basics of control system design: Part 1 – Moving beyond PID

“This series of six articles will explore the use of six variations of P, I, and D gains: Proportional Control, Proportional-Integral Control, Psueodo-derivative feedback with feed-forwared (PDFF), PID control, PID+ control, and Proportional Derivative Control.”

SG2525 – SG3525 – PWM SMPS Regulator Chip

SG2525 – SG3525 – PWM SMPS Regulator Chip. A second generation ic switch mode controller optimized for high frequency.

100kHz Half Bridge Convertor – SG3525

The SG3525A pulse width modulator control circuit offers improved performance and lower external parts count when implemented for controlling all types of switching power supplies. The on-chip +5.1 V reference is trimmed to +/-1% and the error amplifier has an input common-mode voltage range that includes the reference voltage, thus eliminating the need for external divider resistors. Half Bridge, Push-Pull.

SG3525 usage in SMPS 500W – It was used in Parallel for Electroplating with a central Load sharing control between modules.

SG2525 - SG3525 - PWM SMPS Regulator Chip

Specs

  • 8.0 V to 35 V Operation
  • 5.1 V +/- 1.0% Trimmed Reference
  • 100 Hz to 400 kHz Oscillator Range
  • Separate Oscillator Sync Pin
  • Adjustable Deadtime Control
  • Input Undervoltage Lockout
  • Latching PWM to Prevent Multiple Pulses
  • Pulse-by-Pulse Shutdown
  • Dual Source/Sink Outputs: +/- 400 mA Peak

Circuits –

Power Electronics Section

Here are power supply, inverter, drives, chargers and high current equipment diagrams and links. There are Mosfet and Thyristor circuits too.

Power Electronics Section

Power Supplies, Inverters, UPS, Chargers, Electro Plating, Precision Welding-erosion, Coating Metals and many other Processes are made of high current circuits. Even in measurement of parameters like Micro-Ohm high currents are involved. Electronic Circuits are required in such products to give control to time, current, frequency and voltage in order to accomplish with the required precision a process or job.

Power Electronics Section - delabs
In any power equipment, efficiency and reduction of bulk is crucial so SMPS and high frequency control is an important part of this domain. These products also generate EMI-RFI. Product Safety Study is also vital.

The Power Circuits Section has been updated.

The MOSFET in Power Electronics

delabs Notes – In a Circuit Module, if all Power and Signal Polarities are reversed. All NPN to PNP, All N-Channel to P-Channel and Vice Versa. All Diodes and Caps too turned around. This Topsy Turvy or Mirror Design ought to work in Theory. It has worked for some circuits in practice too in my experience. ?

Some believe that N-Channel is more Robust than the P Type. In Bipolar Transistor NPN is more trusted for the final output stages. The NPN Transistor and N-Channel turn-on by a Positive control bias. It may be inappropriate to say this mosfet is NPN or PNP.

The MOSFET in Power Electronics

The traditional metal–oxide–semiconductor (MOS) structure is obtained by growing a layer of silicon dioxide (SiO2) on top of a silicon substrate and depositing a layer of metal or polycrystalline silicon (the latter is commonly used). As the silicon dioxide is a dielectric material, its structure is equivalent to a planar capacitor, with one of the electrodes replaced by a semiconductor.

If the MOSFET is an n-channel or nMOS FET, then the source and drain are “n+” regions and the body is a “p” region. If the MOSFET is a p-channel or pMOS FET, then the source and drain are “p+” regions and the body is a “n” region. The source is so named because it is the source of the charge carriers (electrons for n-channel, holes for p-channel) that flow through the channel; similarly, the drain is where the charge carriers leave the channel. MOSFET – Wikipedia

This application note discusses the breakdown voltage, on-resistance, transconductance, threshold voltage, diode forward voltage, power dissipation, dynamic characteristics, gate charge and dV/dt capability of the power MOSFET.
Application Note AN-1084 Power MOSFET Basics – IRF

A MOSFET is a transistor. It is a Metal Oxide Field Effect Transistor. Here are the symbols for FETs and MOSFETs: The MOSFET How the MOSFET works

The conductivity of the path from Source to drain is controlled by applying a voltage between the gate and the body of the semiconductor. N-channel enhancement MOSFET

See this simple circuit that explains everything
n-channel MOSFET switch – George Watson, Univ. of Delaware, 1996.

EE Journal – Embedded FPGA ASIC Design

Embedded Technology Journal and FPGA Structured ASIC Journal are now in EE Journal

EE Journal – Embedded FPGA ASIC Design

“The first year of a new publication is always exciting, but Embedded Technology Journal first year has been nothing short of stellar. We began, of course, with modest-sized audiences mulling our strange stories about putting tiny little computers into toasters and such. People pondered processors, studied software, meditated about memories, brushed up on busses, wrestled with RTOS, and fumbled with FPGAs. We covered applications ranging from smart phones to avionics and touched on some truly unique systems like golf radar and digital scarecrows.”

An approach to comprehensively verify a multi-clock design

An approach to comprehensively verify a multi-clock design

“One example of a combined solution is outlined in Figure 2, where timing exceptions between synchronous clocks are verified using Atrenta’s SpyGlass-TXV timing exception verification tool and the correct synchronization of interfaces between asynchronous clocks is handled by the SpyGlass-CDC tool, giving complete overall coverage.”

Imagineering On-line Magazine

“Some people collect stamps, coins or baseball cards, I collect electronic circuit schematics. I own several book shelves and file cabinets full of electronic circuit books, IC application manuals and circuit encyclopedias. I often use my collection for reference.”

Imagineering On-line Magazine

David A. Johnson, – P.E. consulting electronics engineer.

(This resource by dave is very important for Electronic Enthusiasts, Engineers and R&D Engineers. I say this as an R&D Professional with more than 20 years off the ground)

Capacitance Proimity Switch Technology -The Design Corner, Imagineering E-Zine

Capacitance Proimity Switch Technology -The Design Corner, Imagineering E-Zine

“These switch circuits used a sensitive high impedance circuit to detect the small AC power line signals, picked up by the human body from nearby appliances.”

(These are the type of technologies that lead to the Touch Screens on Tablets and Phones.

Power Electronics Java Applets

Some very useful, educative and interactive Java Applets. Tutorials around Power Electronics. Includes Diode and SCR Circuits, Controlled 1/3 Phase SCR-Thyristor Bridge Rectifier and Switch-Mode Power Supplies SMPS.

Power electronics-interactive text

They include Simple diode, SCR and thyristor controlled bridge rectifier circuits and most important the Switch-Mode Power Supply SMPS.

Interactive Power Electronics Seminar (iPES)

Interactive Power Electronics Seminar

The following Java applets are part of the Introductory Course on Power Electronics taught by Prof. Kolar at the ETH Zurich. The interactive and animated applets are used as aid for teaching in the classroom and are displayed using a laptop and a beamer. Furthermore, the applets do provide an opportunity for the students to experiment and learn at home more efficiently.

Simulations like these can be made with various methods. Client Side and Server Side. Flash, Java and Ajax(with dhtml) can be client side. Server side are numerous. Perl and CGI, Python, PHP and many more.

Small Tutorials can be made in Flash. More Flexibility and Power in Java. Ajax (implies even DHTML, JS, CSS) also good. Client only Tutors. But larger simulations or Web applications means server side computing. Here the Client side is just GUI and some basic reflexes and data caching. The other CPU/Data load is moved online to servers.

As tools are moving online even EDA, ASIC design and Chip Programming can be made into Webapps or SaaS – Software as a service. This also safeguards the IP and Codebase of developer/programmer/firms better.

Here some power electronics design info is available. Switching-Mode Power Supply Design

At Alexandre Manuel Mota‘s pages you will find – Op Amps for Everyone Design Guide, History of Switched Mode Power Supplies, DC Power Supply Handbook, SWITCHMODE Power Supply Reference Manual, Linear & Switching Voltage Reference Handbook. The above PDF files seem to be good study material, before you design and build your next power supply, SMPS or AC/DC converter. – delabs