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<p>MICRO - 2407</p> <p>User Manual</p> <p>Version 1.0</p> <p>Technical Clarification /Suggestion : N/F Technical Support Division,</p> <p>Vi Microsystems Pvt. Ltd.,Plot No :75,Electronics Estate, Perungudi,Chennai - 600 096,INDIA. Ph: 91- 44-2496 1842, 91-44-2496 1852 Mail : service@vimicrosystems.com, Web : www.vimicrosystems.com</p> <p>PREFACEThis manual is the user guide to the Micro-2407A kit. The primary objective of this manual is to learn DSP fundamental and its Applications using MICRO-2407A processor based trainer kit. This manual consists of seven chapters. In Chapter 1, the hardware features of the Digital Signal Processor TMS320LF2407A is discussed. The complete technical aspects of TMS320LF2407A can be had from "TMS320LF/LC240xA DSP Controllers Reference Guide System and Peripherals " from Texas Instruments. The Hardware configuration of TMS320LF2407A in Micro-2407A is explained in Chapter 2. This chapter also gives the details of resources available in the Micro-2407A. Chapter3 describes how to execute the program in the standalone mode using line assembler. Example programs aimed at explaining the key software features of TMS320LF2407A using line assembler are given in Chapter 4. These examples have been selected for a reasonable and balanced exposure to the important aspects of TMS320LF2407A. Chapter 5 describes how to execute the programs in the serial monitor mode using cross assembler. Chapter-6 describes how to generate various PWM outputs like Fixed Frequency PWM, Sine Modulated PWM etc. These examples helps to study the generation of PWM signal using TMS320LF2407A and useful in developing the real time application programs. For more examples and application, refer the manual "Applications of Micro-2407A in Power Electronics" We assume that the reader is familiar with the fundamentals of DSP. Further we assume that the reader is familiar with the general ideas of assembly level programming. For the beginners of DSP, it will be very helpful to refer the good fashioned DSP book "A Practical approach to Digital Signal Processing" by Dr.K.Padmanabhan, B.E., M.Sc. (Engg), Ph.d., Dr.S. Ananthi, B.E., M.E., Ph.d., Mr.R.Vijayarajeswaran, B.E., M.E. We shall be grateful to consider suggestions for further improvement of this manual.</p> <p>Write to:The Customer-Support Division,</p> <p>Vi Microsystems Pvt. Ltd.,Plot No.75, Electronics Estate, Perungudi, Chennai - 600 096. PHONE : FAX : Web : E-MAIL: # (044) 2496 3142. # (044) 2496 1536. www.vimicrosystems.com sales@vimicrosystems.com</p> <p>Micro-2407A User Manual</p> <p>Digital Control for Electric Drives</p> <p>CHAPTER 1DIGITAL CONTROL FOR ELECTRIC DRIVES1.1. INTRODUCTION:</p> <p>The Motor Control industry is a strong aggressive sector. Each industry to remain competitive, must reduce costs but also has to answer to power consumption reduction and EMI radiation reduction issues imposed by governments and power plant lobbies. The results of these constraining factors are the need of enhanced algorithms. DSP technology allows to achieve both, a high level of performance as well as a system cost reduction. Texas Instruments launches a new DSP, referenced TMS320C240, specifically designed for the Digital Motor Control segment. This device combining a 16 bit fixed-point DSP core with microcontroller peripherals in a single chip solution is part of a new generation of DSPs called the DSP controllers. 1.2. MOTOR CONTROL DRIVES:</p> <p>Electric motors now form a big part in our daily life especially with domestic applications like hairdryers, fans, mixers and drills that we do not really pay any attention to them. We just expect all these items to do their job without even giving a thought to the motor itself and its rather complex electronics. Among all the existing motors on the market there are three classical motors: the Direct Current with commutators (wound field) and two Alternative Current motors the synchronous and the asynchronous motors. These motors, when properly controlled, produce constant instantaneous torque (very little torque ripple) and operate from pure DC or AC sine wave supplies.</p> <p>Implementation of advanced motor drive systems requires the following features from a typical motor controller</p> <p>Vi Microsystems Pvt. Ltd.,</p> <p>[1-1]</p> <p>Micro-2407A User Manual *</p> <p>Digital Control for Electric Drives</p> <p>Capability of generating multiple high frequency, high-resolution PWM waveforms. Fast processing to implement advanced algorithms to minimize torque ripple, on line parameter adaptation, precise speed control etc. Implementing multiple features using the same controller (motor control, power factor correction, communication, etc.) Making the complete implementation as simple as possible (reduced component count, simple board layout and manufacturing etc.) Implementing a flexible solution so that future modification can be realized by changing software instead of redesigning a separate hardware platform.</p> <p>*</p> <p>*</p> <p>*</p> <p>*</p> <p>A new class of DSP controllers has addressed these issues effectively. These controllers provide the computational capability of a DSP core and integrate useful peripherals on chip to reduce the total chip count. 1.3. THE DSP IN MOTOR CONTROL</p> <p>Market analysis shows that most of all industrial motor applications use AC induction motors. The reasons for this include high robustness, reliability, low price and high efficiency (up to 80%). However, the use of induction motors also has its disadvantages, these lie mostly in its difficult controllability, due to its complex mathematical model, its non linear behaviour during saturation effect and the electrical parameter oscillation which depends on the physical influence of the temperature. Traditionally motor control was designed with analog components, they are easy to design and can be implemented with relatively inexpensive components. However, there are several drawbacks with analog systems. Aging and temperature can bring about component variation causing the system to need regular adjustment, as the parts count increases the reliability of the system decreases. Analog components raise tolerance issues and upgrades are difficult as the design is hardwired. Digital systems offer improvements over analog designs. Drift is eliminated since most functions are performed digitally, upgrades can easily be made in software and part count is also reduced since digital systems can handle several functions on chip. Digital Signal Processors go on further to provide high speed, high resolution and sensor less algorithms in order to reduce system costs. Providing a more precise control to achieve better consumption or radiation performances often means performing more calculations, the use of some 1-cycle multiplication &amp; addition instructions included in a DSP speeds-up calculations. Generally fixed point DSPs are preferred for motor control for two reasons. Firstly, fixed point DSPs cost much less than the floating point DSPs. Secondly, for most application a dynamic range of 16 bits is enough. If and when needed, the dynamic range can be increased in a fixedpoint processor by doing floating-point calculations in software.</p> <p>Vi Microsystems Pvt. Ltd.,</p> <p>[1-2]</p> <p>Micro-2407A User Manual 1.4.</p> <p>Digital Control for Electric Drives</p> <p>BENEFITS OF THE DSP CONTROLLERS</p> <p>The performances of a motor are strongly dependent on its control. DSP controllers enable enhanced real time algorithms as well as sensor less control. The combination of both allows reducing the number of components and to optimize the design of silicon, to achieve a system cost reduction. A powerful processor such as a DSP controller does the following: v Favours system cost reduction by an efficient control in all speed range implying right dimensioning of power device circuits v Performs high level algorithms due to reduced torque ripple, resulting in lower vibration and longer life time v Enables a reduction of harmonics using enhanced algorithms, to meet easier requirements and to reduce filters cost v Removes speed or position sensors by the implementation of sensorless algorithms v Decreases the number of look-up tables which reduces the amount of memory required v Real-time generation of smooth near-optimal reference profiles and move trajectories, resulting in better-performing v Controls power switching inverters and generates high-resolution PWM outputs provides single chip control system For advanced controls, DSPs controllers may also performs the following: v Enables control of multi-variable and complex systems using modern intelligent methods such as neural networks and fuzzy logic. v Performs adaptive control. DSPs have the speed capabilities to concurrently monitor the system and control it. A dynamic control algorithm adapts itself in real time to variations in system behavior. v Provides diagnostic monitoring with FFT of spectrum analysis. By observing the frequency spectrum of mechanical vibrations, failure modes can be predicted in early stages. v Produces sharp-cut-off notch filters that eliminate narrow-band mechanical resonance. Notch filters remove energy that would otherwise excite resonant modes and possibly make the system unstable. The TMS320C24x DSP includes the same advantages as the microcontroller but also offers higher speed, higher resolution, and capabilities to implement the mathintensive algorithms to lower the system cost. The high speed is attributable mainly to the dual bus of the Harvard architecture as well as single-cycle multiplication and addition instructions. One bus is used for data and the other is used for program instructions. This saves time because each is utilized simultaneously. Traditionally, cost has been a potential disadvantage of the DSP solution, but this aspect has diminished with the continuing decline of DSP costs. DSP controllers enable enhanced, real-time algorithms as well as sensor less control. The combination reduces the number of components and optimizes the design of silicon to achieve a system cost reduction.</p> <p>Vi Microsystems Pvt. Ltd.,</p> <p>[1-3]</p> <p>Micro-2407A User Manual</p> <p>Digital Control for Electric Drives</p> <p>DSPs are capable of processing data at much faster rates than microcontrollers. For example, the speed of the DSP allows it to estimate motor velocity, a task accomplished by a tachometer in analog and microcontroller systems. 1.5. APPLICATIONS</p> <p>The target applications for a fixed point DSP controller having the necessary features are where the above-mentioned advantages meet the customers needs. Typical end equipment applications with an advanced control are: v v v v 1.6. Appliances (washers, blowers, compressors) HVAC (heating, ventilation and air conditioning) Industrial servo drives (Motion control, Power supply inverters, Robotics) Automotive control (electric vehicles). DIGITAL CONTROLLER REQUIREMENTS</p> <p>The following list highlights the digital controller requirements. v Calculations powerful enough to implement advanced and math-intensive control algorithms, such as v Fast response to events to obtain input signals and to unexpected events to secure the system v Accurate resolution to minimize quantization errors; therefore, a precise digital control system is offered v High sampling rate to avoid aliasing introduced by sampling effects v Required peripherals to reduce CPU overhead and system cost</p> <p>1.7.</p> <p>PROCESSOR REQUIREMENTS The following list highlights the processor requirements.</p> <p>v Strong calculating power for advanced and math-intensive control algorithms v Capability to support large word lengths for required resolution and dynamic range v Small interrupt latency and fast branch operations capabilities to facilitate quick response to events, including unexpected events v High-MIPS CPU to increase the range of the sampling frequency v Integrate the application-specific peripherals with the processor, such as timers, A/D converters, PWM generators, and communication interfaces. Hence, CPU overhead and total system costs are reduced.</p> <p>Vi Microsystems Pvt. Ltd.,</p> <p>[1-4]</p> <p>Micro-2407A User Manual 1.8.</p> <p>Digital Control for Electric Drives</p> <p>TI TMS320C24X DSP FAMILY the Optimal Digital Control System Solution</p> <p>A new class of DSP controllers is becoming a viable option for even the most cost sensitive applications like appliances, HVAC systems etc. In addition to traditional mathematical functions like digital filter, FFT implementations, this new class of DSPs integrates all the important power electronics peripherals to simplify the overall system implementation. This integration lowers over all part count of the system and reduces the board size. The TMS320C24x, the first single-chip DSP solution for the digital control system market, integrates the TI 16 bit, fixed-point TMS320C2xLP DSP core with several microcontroller peripherals. The DSP core itself has up to 20 MIPS (50 ns cycle time) speed and can perform the useful multiply/accumulate instruction in a single cycle. The DSP controller TMS320F240 from Texas Instruments is utilized to implement a three-phase AC induction motor drive with multiple functions. These functions include basic motor control with closed loop speed control, input power factor correction using boost topology and serial communication. TMS320F40 has a 20MIPs 16 bit fixed point DSP core. It also integrates the following power electronics peripherals 12 PWM channels (out of which 9 are independent), three 16 bit multimode general purpose timers, 16 channel 10 bit ADC with simultaneous conversion capability, four capture pins, encoder interface capability, SCI, SPI, Watch Dog etc. Six PWM channels (PWM1 through PWM6) control the three-phase voltage source inverter. These six PWM channels are grouped in three pairs (PWM 1&amp;2, PWM 3&amp;4, PWM 5&amp;6). Three compare registers, called Full Compare, are associated with each PWM channel pair. The compare register values are updated to obtain the proper PWM output. The on-chip software programmable, dead band module provides sufficient dead time to avoid shoot through fault. There are three more PWM channels left to implement other functions like power factor correction. 1.9 3.3V DSP FOR DIGITAL MOTOR CONTROL New generations of motor control digital signal processors (DSPs) lower their supply voltages from 5V to 3.3V to offer higher performance at lower cost. Replacing traditional 5V digital control circuitry by 3.3V designs introduce no additional system cost and no significant complication in interfacing with TTL and CMOS compatible components, as well as with mixed voltage ICs such as power transistor gate drivers. Just like 5V-based designs, good engineering practice should be exercised to minimize noise and EMI effects by proper component layout and PCB design when 3.3V DSP, ADC, and digital circuitry are used in a mixed signal environment, with high and low voltage analog and switching signals, such as a motor control system. In addition, software techniques such as Random PWM met...</p>


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