greenpowerZONE Products for the week of June 11, 2007
Texas Instruments Says....
Floating Point Digital Signal Controllers Enable "Greener" Industrial Applications
TMS320F2833x DSCs boost performance by 50%, simplify software development
Helping industrial control designers increase energy efficiency through higher performance and precision for digital power, intelligent sensing and motor control applications, Texas Instruments Incorporated has announced the industry's first floating point digital signal controllers (DSCs). The new TMS320F2833x devices provide 300 million floating point instructions per second (MFLOPS) performance at 150 MHz while providing the lower costs typically associated with fixed point processors. This performance combined with simplified software development common to floating-point processors allows solar power inverters to more efficiently convert energy from photovoltaic (PV) panels, better power efficiency and performance to variable speed AC drives and greater performance to automotive radar applications.
New Controllers Increase Performance by 50 Percent and Keep Compatibility
The new F2833x floating-point controllers will increase performance by an average of 50 percent over the previous leading digital signal controllers while operating at the same 150 MHz clock rate. Some algorithms, such as a Fast Fourier Transform (FFT) will see a 200 percent improvement over an equivalent 32-bit fixed-point implementation. This is due to the tight integration of the F2833x floating-point unit into the C28x central processing unit (CPU).
Overall system bandwidth is increased with the addition of a six-channel direct memory access (DMA) controller that offloads the CPU from servicing the ultra-fast, on-chip analog-to-digital converter (ADC) along with user-configurable 16- or 32-bit external memory interface and high-speed serial ports.
Motor Control, Alternative Energy Look for Greater Efficiency and Performance
According to the European Photovoltaic Industry Association (EPIA), in 2005 there were 1397 Megawatts (MW) of installed solar capacity and that number is expected to grow to 5550 MW by 2010. Solar inverters manufacturers -- of which eight of the top ten use TI DSCs-are continually looking at ways to make the conversion more efficient. With the combination of performance, integration and ease of development, designers using F2833x controllers can maximize peak efficiency of the system through effective Maximum Power Point Tracking (MPPT) algorithms and dynamic algorithm adjustment across all load conditions, including cloudy and low light days. F2833x controllers also have the performance to integrate additional system features like data logging, power line communications or inverter synchronization to the utility grid.
Simplified Development And Complete System Integration
Software developers typically begin creating algorithms in a floating-point environment for validation and then convert the code to run on fixed-point devices. Developers can now eliminate the weeks, often months, contending with scaling, saturation and adjustment of numerical resolution required in fixed-point implementations.
All F2833x controllers offer exceptional system integration for single-chip control applications from signal input to high-resolution control output. The on-chip 12-bit, 16-channel analog-to-digital converter (ADC) operates at 12.5 mega-samples per second -- the fastest on-chip ADC operation of any digital signal controller. Other signals from quadrature encoder pulse (QEP) modules and Hall effect sensors are input via dedicated QEP and event capture interfaces. The F2833x controller series features up to 18 PWM channels, six of which include TI's unique high-resolution PWM technology with 150 pico-seconds resolution.
Communication interfaces include CAN, I2C, UART, SPI and TI's Multi-channel Buffered Serial Ports (McBSP). System integration is completed with the large on-chip memory available on the F2833x controllers.
EN-Genius Says...
With energy prices spiking and Global Warming in the headlines, high-efficiency motor controllers have suddenly become a hot topic. But this is old news to TI, which won one of our Product of the Year awards with their first series of low-cost digital signal controllers (the TMS320C2000) that started changing the economics of smart power conversion back in 2005. By integrating some carefully-selected I/O and memory resources around a low-power fixed-point 32-bit DSP core, they created a family of low-cost controllers that helped change the economics of energy-efficient white goods and the synchronous inverters used in solar and wind power systems Their new F2833x DSP-based controller series adds the floating point capabilities and expanded channel capacity needed to bring the same benefits to higher-powered industrial applications.
Packing 150 - 300 MFLOPS and hardware floating point capabilities, the new controllers bring around 50% more computing power to the table than their fixed-point ancestors. But raw compute power is only half the story here. The F2833x floating-point architecture accelerates common functions like square roots and FFTs because they require far fewer instructions and clock cycles to execute. TI claims that the FP support also simplifies moving algorithms from MatLab, or other development tool, by eliminating the need for conversion from their native floating point format. Designers who have already designed with the fixed-point TMS320C2000 will appreciate that the new series is code-compatible, allowing you to re-use all your existing software.
 The new controller-augmented on-chip peripherals include 18 PWM controllers (up from 12) which allow it to control several multi-phase motors at a time (see Fig. 1). Six of the PWMs are capable of high-precision 150 ps timing resolution (Vs 3 on the earlier chip) that deliver 17 bit equivalent resolution at a 50 Hz sampling rate, and 11.4 bits at 2.5 MHz. This higher resolution is not as critical for motor control, but provides a big advantage for power conversion and precise shaping of waveforms, and especially useful in grid-tied inverters where exact phase matching to the power line is necessary.
TI has also doubled on-chip memory to 512 kbyte of Flash and 68 kbyte of RAM. The new DMA controller will help speed block data movements and free the DSP for more productive tasks. Instead of simply tacking on the new logic onto the existing design, TI went through a fairly extensive re-design that kept its power consumption about the same as the last generation of devices.
The added compute horsepower and PWM channels make these signal controllers a great choice for your next motor control system where their ability to run fast, complex control algorithms will help them maintain peak efficiency over a wider load range. There are some other great ultra-high-efficiency controllers from companies like International Rectifier which are somewhat customized for specific applications like air conditioners and washing machines, but most of them don't have the versatility or large number of PWM channels required for general-purpose industrial applications.
Since roughly 2/3 of industrial electricity consumption goes into powering the motors in things like robotics, machine tools and conveyor systems, the 25% - 75% energy savings a true variable-speed system can deliver can make a huge difference to a company's operational costs as well as its carbon footprint. And since a recent study by ABB indicates that only 5% - 10% of today's industrial motors are run as variable-speed drives, there should be a large market for retrofit as well as new equipment.
The TI DSCs should also find lots of applications in larger-sized solar/wind inverters as their ability to handle multiple inverter channels drive down solution cost and its precision PWM channels deliver high efficiency. The embedded processing power these controllers pack also makes it easy to implement maximum power point tracking techniques, mentioned in the release above, which adjust the converter's impedance to ensure the solar arrays are running at their highest possible efficiency. Since the F2833x series is fully qualified for automotive applications, I'd also expect that the extra processing power it provides will make it very attractive for controlling electric/hybrid vehicle powertrains.
Samples of the F28335, F28334, and F28332 devices will be available in September 2007 and will be fully AEC Q-100 qualified for automotive applications. Hardware and software development tools, including the Code Composer Studio Integrated Development Environment will be available with the F2833x controllers.
 Developers can start programming today using any available F28x based eZdsp development tool and IQ Math, TI's virtual floating point software library. Software written with IQ Math will automatically run on the F2833x controllers.
The F2833x devices will also be supported by the TI C2000 Digital Motor Control and Digital Power Supply software libraries. This free, fully documented software provides aides developers in quickly prototyping a motor control, or digital power system, using C2000 controllers and can be downloaded here. F2833x controllers are also fully software compatible with all previous TMS320C28x controllers.
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