Three years ago I made a prediction. By 2030, it would be mandatory that all motors would be fitted with a drive. At the time I was speculating on where the next 20 to 30 years would take the variable speed drives business as fuel prices continue their fluctuating, yet rampant spiral upwards. But the pace of change is possibly faster than even I anticipated.
Earlier this year it was announced that, subject to the draft regulation covering the ecodesign requirements for motors being adopted by the European Commission, the minimum energy performance of motors will be IE3 (or IE2 if the motor is combined with a variable speed drive) from 2015. This will clearly escalate the penetration into the market of variable speed drives.
But if you think about it, this pace of change should come as no surprise. I hear people say that variable speed drives are a mature market. But 30 years is such a short timeframe. Take any other product from automobiles, to cameras, to phones. Each has been around for well over 100 years but none have yet peaked in terms of design or functionality.
For the automotive industry, new technology, materials and fuels have pushed the boundaries of imagination. And I see exactly the same happening with drives. We are now moving from push marketing, where manufacturers were fighting for the mind share and wallet of a cynical audience, to pull marketing - customers are now demanding variable speed drives for the immense benefits that they can bring. One day every motor driven application will benefit from a drive - whether white goods or brown goods. This has led me to reassess my predictions as to where the technology of variable speed drives is heading. I see six areas of progress over the next few decades.
Reduced cost, size and parts count - One common trend among all variable speed drives manufacturers is the aim for smaller, cheaper and more powerful drives. Several factors drive this cost, size and parts count reduction. Over the next ten years, we can expect drives, particularly low power ones, to shrink substantially, as there seems to be no end to the miniaturisation of microelectronics.
Component development continues unabated. New low loss materials are being developed for the semiconductor switches that allow the drives to operate at higher temperatures as well as improvements and innovations in inductive components and low-capacitance intermediate circuitry. This will make it possible to further shrink the size of the drives and increase the power density. The compact size and the high temperatures, place special demands on the cooling requirements and developments are underway to improve cooling techniques. Cooling is a major hurdle that needs to be overcome.
But we are getting there. In 1976, an 11 kW ABB drive had a power density of 100dm3/kW. Thirty years later, an 11kW ABB drive achieved a power density of 5dm3/kW. And in 2008 a 22kW ABB machinery drive hit a new world record with only 0.3dm3/kW. Even the larger drives are shrinking rapidly. For the same frame size used in 2003, ABB has managed to increase the power output from 110kW to 160kW.
Environmental robustness - The continuous reduction of cost - and price - of drives makes it possible to penetrate totally new drive applications that were unimaginable two decades ago. Low voltage ac drives, for example, continue their inroads into the domain of servos. At one time, only a servo drive would do for highly accurate positional control. As drives become more reliable, smaller and cost-effective, then the range of applications broadens. Inevitably some applications are in harsh outdoor environments and developments are underway that will enable a drive to work outside in all conditions. Better manufacturing techniques will mean that drives can be customised to any application as they are built.
And because of the high demand, drives manufacturing will become completely automated and I foresee modern plants churning out drives by the millions.
Ease-of-use and intuitiveness - Let's face it, despite the best efforts of the manufacturers, keypads - even those that are as simple to use as a mobile phone - can be a nuisance. And as new applications in domestic and other non-industrial markets take off, the demand for ease-of-use will escalate. In the future, the user interface will certainly be simplified to the extent that, one day perhaps drives might not even need a keypad.
These drives could be completely integrated into the machine and the user may not even interact with the drive at all. In fact, everything could be controlled through one hand-held PDA with access to the variable speed drive through a unique Internet address. All the parameters and settings of the drive can be accessed over the Internet, in most cases wirelessly. But that is probably many years away.
Improved reliability - Reliability is the most important single purchasing factor among drive customers. As such, much R&D investment is being made into ensuring components have extremely high mean time between failures. In parallel, work is underway exploring wireless options for high powers which would also help alleviate challenges presented by RFI and EMC, thereby further improving reliability.
Information access - One of the biggest advances in recent years is the intelligence that is now built into drives. Today's drives have incredible measuring, data gathering and processing capability and seemingly endless I/O. And this intelligence is set to increase to take in valuable information from the entire power conversion chain from supply network to end user process. Along the way, developments will see the avoidance of extra sensors; and greater built-in functionality leading to reduced maintenance, less cabling and faster installation. Drives will feature proactive monitoring and diagnostics; remote monitoring and diagnostics; wireless communication, and support for asset and lifecycle management.
In fact, such is the onboard intelligence that soon drives will become an integral part of control, maintenance and monitoring systems. Self-healing control systems, with control functions spread between a number of drives, will be the order of the day; if one drive develops a fault or error, another drive diagnoses and fixes it. Provided the fault is software, the drives in close proximity actually look after each other. At commissioning the drive automatically detects the characteristics of the load or process and uses this data to set up its own parameters.
Communications are also expected to improve dramatically. Ethernet will allow drives to handle far larger amounts of monitoring information, making an intelligent drive a valuable tool for preventative maintenance programmes. The process itself would also benefit from monitoring by the drive, with the data collected describing the state of the process. Using Ethernet, it would be easy to interrogate each drive and build up a highly detailed picture of the entire process.
Energy efficiency - 'Environmental footprint' will become an important parameter for industry, and products will be assessed on how quickly the energy used during their manufacture can be recovered. Today a drive can claim to be the most environmental friendly product in the world. With just half a day's use, a variable speed drive can compensate for the environmental cost of its own manufacture and disposal.
A study, carried out in co-operation with Tampere University of Technology, demonstrates how long drives of various sizes need to be used before they begin making a positive contribution to the environment. The ecological payback times were short in all instances, decreasing with higher power ratings. The 0.75kW drive compensated for its global warming potential in six days; for the 7.5kW drive it was 1.1 days and for the 250kW drive it was half a day.
Investment calculations today are based on financial payback time - companies normally want their money back in two years or less. Within the next decade there will have been a sea change in the way companies look at investment decisions and they will be just as keen to save CO2 as they are saving money today.
With increasing legislation, regulations and directives related to energy efficiency and the environment the role of the variable speed drive is going to be even bigger. Just take a look at the recent EU motor legislation to see the impact. R&D departments are exploring ways to exploit the demand for energy efficiency and we will soon see functionality around environmental friendliness and energy efficiency by way of energy efficient motor control algorithms.
As for environmental impact, well we already have developments aimed at making drives friendly to networks and motors. We have active rectifiers low harmonic converters, filter based systems, multilevel topologies - the list goes on. So, ac drives are set to become smaller and more intelligent, have better communications and be easier to install and control. At the same time, they will become suitable for many more applications, all at a constantly reducing price and with improved, customised service deals. What better future could drives users ask for?
Steve Ruddell is general manager, Drives and Motors, ABB Limited