Trend

UPS reloaded

DSP technology helps vendors of UPS systems design devices that last longer and perform better with fewer components, says Atanu Kumar Das

Digital Signal Processing (DSP) is catching on like wildfire among the makers and users of Uninterruptible Power Supply (UPS) systems as the technology ensures better output voltage conditions and power quality at all times for sensitive loads on servers, PCs and other computing devices. According to Deepak Sharma, Managing Director, Eaton Power Quality Corporation, “We started using DSP technology around six years ago when this technology was first introduced in India. At that time, it was used sparingly, but now we use it in all the UPS systems we manufacture. Users have witnessed the benefits of DSP technology as it ensures a longer life for the UPS systems as signalling is done at a low voltage. Moreover, vendors who have been using DSP have the advantage of offering the best value to their customers.” Sharma adds that some vendors are still not using this technology to its full potential because of the high cost of design and implementation, as well as a lack of technical knowledge.

Comments Somnath Singha, Corporate Champion, Power, Emerson Network Power (India), “One of the primary benefits of DSP is that it can do floating point calculations quickly, thereby permitting equipment to work at a higher frequency. It does multiple functions such as calculation, measurement and monitoring simultaneously.”

Singha added that this technology was introduced in the early nineties in UPS systems with smaller ratings. In the last three to four years, it has become more common. “Moreover, it ensures a longer life for a UPS since failures associated with analog components have vanished. Since the number of devices in DSP-based UPS systems are fewer, it increases the life and uptime of the device,” he explains.

Most channel partners say DSP technology has ensured that user satisfaction is higher than ever. Says Chander Shekhar, Managing Director of Revika Computronix, “We have noticed that users who use UPS with DSP technology are more satisfied than others as it increases the life-span of the UPS system. Moreover, in rural areas where low voltage is normal, DSP technology ensures that the UPS system runs smoothly.”

Standalone technology

DSP eliminates all 50/60 Hz magnetics and ‘control pots,’ facilitating easy setup, drift-free operation and a pristine output signal. True Pulse Width Modulation (PWM) technology is achieved through the use of DSP by enabling the IGBTs (Insulated Gated Bipolar Transistors) to work at their highest capacity, increasing overall system reliability and ensuring near-perfect power on the output.

The real-time performance of DSP is how a UPS achieves high performance with fewer components. DSP allows for the implementation of control algorithms that increase overall system performance while simultaneously increasing measures of chronological time, number of battery discharges, battery temperature and system loading to determine the remaining runtime and battery life.

DSP technology ensures high reliability of a UPS and enables faster response times of a UPS at less than 1 millisecond. Sharma states that DSP is the latest and most popular technology worldwide. “The Indian UPS market is huge and sooner rather than later we have to adopt global technologies to meet market demands,” he reflects.

According to IDC, 2,28,088 UPS systems valued at Rs 120.81 crore were shipped through the channel in Q4 2004.

Slimming the UPS

DSPs let UPS designers replace bulky transformers, relays and mechanical bypass switches with smaller functional equivalents. DSP implementations also facilitate other design benefits, including increased power efficiency, power density and smaller product footprint with less weight—a necessity in space-constrained data centres.

A DSP controller manages many UPS functions including sensing and controlling input and output voltage, setting and controlling the rectifier (a boost converter) for input power factor correction and for regulating the DC voltage into the inverter, setting and controlling the inverter (a buck converter) for output voltage, regulating frequency, and controlling the battery charger. It also interfaces with power management software through communication port cards and switches to electronic bypass.

DSP technology enables the implementation of sophisticated UPS topologies and controls. The DSP can simultaneously control multiple power converters to optimise system efficiency and other performance characteristics such as advanced battery management for extended battery life, improved output voltage regulation, enhanced bypass capability, and communication with networks and with other equipment. The result is a higher performance UPS in smaller, lighter, more reliable designs—an advantage for space-constrained equipment racks and cost-conscious, co-located data centres.

What lies ahead

DSP technology is becoming more popular in the country because of its benefits. It will however take some time before all vendors start adopting it as it requires high-tech R&D and test facilities. As Singha puts it, “The pre-requisite for adopting this technology is to have a high-end technology infrastructure. Not many vendors of UPS systems have this today, and that is the reason we see [mainly] top vendors adopting this technology. But users have already started reaping the benefits of DSP—the technology that is here to stay.”

atanu@expresscomputeronline.com