VoltAmpere

A South African-developed load-adaptive variable-speed generator system sets unprecedented power supply standards for defence applications

Quantum leap in
on-site power
generation technology

A seamless, high-quality electric power supply, generated on-site or on-board, is increasingly indispensable to successful battlespace operations, whether in terrestrial warfare, ground power units used in aerial operations or marine applications. The need for on-site power suitable for computers, key communications installations and medical equipment also applies to civilian emergency situations (including those caused by natural disasters such as earthquakes and floods) where security forces and rescue teams are called in to provide services, including field hospitals, against a background of grid power and telecommunications disruption.
The problem is that although conventional on-site electricity generators have improved considerably in the past half-century, their technology, based on constant-speed diesel engines, remains technically (and economically) flawed.

A new generator technology, developed over the past seven years by the VoltAmpere Group of Pretoria, South Africa, and patented worldwide, represents a quantum leap that will change the face of the industry for the foreseeable future.

The heart of the new technology, named Hygen ("hybrid generator"), is in brief a microcomputer-controlled power electronic system which serves as an intelligent hub between a variety of potential energy inputs and various operational applications.

In its basic configuration, it interfaces only with an engine-driven alternator, to serve as a base load generator providing a high quality power output with unequalled fuel efficiency.

However, the various energy sources compatible with the Hygen system cover the full range - modern variable-speed diesel/ gasoline engines as well as gas turbines (applicable to defence operations), and solar, wind or micro-hydro inputs (for economy in the parallel commercial systems). The applications to which the system can be put likewise cover the full range, from base load to standby and (with energy storage) UPS (uninterruptible power supply) functions, as well as load levelling/ peak shaving. The range of special applications is limited only by the ingenuity of users and their engineers.

In a typical configuration (see Fig.1) the Hygen system combines its variable-speed engine and permanent magnet alternator with the energy storage batteries, a power electronic converter and a microprocessor controller. The engine drives the alternator at variable speed to produce a variable voltage and frequency. The alternator output is converted to constant DC power, which, if required is inverted to an AC output of desired voltage and frequency. The storage batteries are connected to the DC power through devices which control the flow of power (charge/discharge).

Fig 1: The Hygen system

The energy storage facility gives the Hygen system an impressive power range, enabling the use of a smaller engine and hence more easily deployed unit than in the case of a constant-speed unit. Sharp increases in load demand (such an electric motor starting transient) are met by the system’s energy storage batteries for the few seconds while the engine is accelerating to meet the new load demand - with the system’s power convertors preventing interim fluctuation in output voltage and frequency (irrespective of whether the load demand is increasing or decreasing).

The energy storage batteries provide the UPS feature, with the engine extending the UPS autonomy for as long as there is fuel in the tank.

The storage batteries (acting in concert with the engine) can be customised to take quite spectacular load demand spikes in their stride. Typically, a Hygen unit can provide an overload capacity twice the rated power of the engine for several minutes. The energy storage feature also permits automatic engine shutdown at times of low load demand, with automatic startup when the load increases.

The effect of the microprocessor control system is that it optimises engine operation according to the load demand, and produces a constant voltage and frequency output suitable for sensitive modern electronic appliances (see Fig.2). It does so even under the most abusive load conditions with which conventional systems cannot cope without sustaining ultimately terminal engine damage.

Fig 2: Hygen output voltage in worst-case load scenario

The Hygen system achieves this operational efficacy with a low fuel consumption. Its energy storage feature and variable-speed operation avert the need for a fuel sapping dummy load to protect the engine against light loading, and fuel input is thus proportional to electrical power output. The effect of this is quite dramatic at low load levels (see Fig.3).

Fig 3: Fuel economy for constant and variable speed operation

The avoidance of light-loading reduces engine maintenance costs and extends engine life up to three times that of the engines used in conventional gensets, according to computer simulations.

The system can be optimised for compactness and light weight where the user deems these features to be more important than economy of operation, which may well be the case in some defence operations.

Options include self-diagnostics and remote control by PC.

Origin of the technology

VoltAmpere commenced business 28 years ago as a rewinding shop and went on to undertake maintenance, repair and remanufacturing work on a wide range of electrical machines. The company was fortunate to win a number of maintenance contracts for large fleets of gensets, amongst them that of the SA National Defence Force, including in field operations hundreds of kilometres from the nearest industrial facility. Company chairman Manuel da Ponte explains: "This work identified for us the inherent shortcomings of conventional gensets, and set us thinking how they could be overcome."

A major problem identified was the constant-speed operation of the heavy duty diesel engines in use, which necessitated over-sizing the genset in order to cope with, amongst others, peak load conditions. Yet outside of peak consumption periods, demand averaged only 20-30% of maximum in a common load profile. The resultant light loading caused damage to engines due to oil dilution and carbon build-up. Where a dummy load was used to avert this cause of premature engine failure, the penalty was increased fuel consumption - vastly out of proportion to the energy output (see Fig.3). "A very poor trade-off," as Mr da Ponte put it.

A further problem lay in output power fluctuations caused by the inability of the constant-speed gensets to respond to the peaks and spikes characteristic of real world load profiles. Fluctuating voltage and frequency might have been acceptable to the load devices of past generations - but not to today’s sensitive electronic appliances.

The VoltAmpere engineers perceived that what was needed, in a remote bush camp for example, was a system capable of providing power in a scenario typically including workshop welders, water pumps starting up and other notorious voltage distorters kicking in without warning. It had to provide this without compromising the voltage quality for the modern computers, radar, communications and field hospital equipment on which the security and well-being of the camp relied. A tall order indeed!

They accordingly embarked upon a seven-year research and development programme, culminating in the Hygen technology with worldwide patents.

The Hygen system can be packaged to customers' specifications, similar to the packaging of conventional generator systems.

Production

Hygen systems at present come in 6, 12 and 24 kVA (single-phase) models, with larger models and diverse applications in the pipeline. They are currently hand manufactured in VoltAmpere’s Pretoria workshop, but plans are in hand for industrialisation and manufacture for the world market. However, regional production under licence is an option for negotiation where major defence users require manufacture within their own borders for strategic reasons.

Mr Manuel da Ponte, VoltAmpere:

Tel +27 12 328 6551 Fax +27 12 324 4203

>>>>> e-mail >>>>> vanetcom@cis.co.za


A South African-developed load-adaptive variable-speed generator system sets unprecedented power supply standards for defence applications
	Quantum leap in on-site power generation technology
	A seamless, high-quality electric power supply, generated on-site or on-board, is increasingly indispensable to successful battlespace operations, whether in terrestrial warfare, ground power units used in aerial operations or marine applications. The need for on-site power suitable for computers, key communications installations and medical equipment also applies to civilian emergency situations (including those caused by natural disasters such as earthquakes and floods) where security forces and rescue teams are called in to provide services, including field hospitals, against a background of grid power and telecommunications disruption. The problem is that although conventional on-site electricity generators have improved considerably in the past half-century, their technology, based on constant-speed diesel engines, remains technically (and economically) flawed. A new generator technology, developed over the past seven years by the VoltAmpere Group of Pretoria, South Africa, and patented worldwide, represents a quantum leap that will change the face of the industry for the foreseeable future. The heart of the new technology, named Hygen ("hybrid generator"), is in brief a microcomputer-controlled power electronic system which serves as an intelligent hub between a variety of potential energy inputs and various operational applications. In its basic configuration, it interfaces only with an engine-driven alternator, to serve as a base load generator providing a high quality power output with unequalled fuel efficiency. However, the various energy sources compatible with the Hygen system cover the full range - modern variable-speed diesel/ gasoline engines as well as gas turbines (applicable to defence operations), and solar, wind or micro-hydro inputs (for economy in the parallel commercial systems). The applications to which the system can be put likewise cover the full range, from base load to standby and (with energy storage) UPS (uninterruptible power supply) functions, as well as load levelling/ peak shaving. The range of special applications is limited only by the ingenuity of users and their engineers. In a typical configuration (see Fig.1) the Hygen system combines its variable-speed engine and permanent magnet alternator with the energy storage batteries, a power electronic converter and a microprocessor controller. The engine drives the alternator at variable speed to produce a variable voltage and frequency. The alternator output is converted to constant DC power, which, if required is inverted to an AC output of desired voltage and frequency. The storage batteries are connected to the DC power through devices which control the flow of power (charge/discharge).

	Fig 1: The Hygen system The energy storage facility gives the Hygen system an impressive power range, enabling the use of a smaller engine and hence more easily deployed unit than in the case of a constant-speed unit. Sharp increases in load demand (such an electric motor starting transient) are met by the system’s energy storage batteries for the few seconds while the engine is accelerating to meet the new load demand - with the system’s power convertors preventing interim fluctuation in output voltage and frequency (irrespective of whether the load demand is increasing or decreasing). The energy storage batteries provide the UPS feature, with the engine extending the UPS autonomy for as long as there is fuel in the tank. The storage batteries (acting in concert with the engine) can be customised to take quite spectacular load demand spikes in their stride. Typically, a Hygen unit can provide an overload capacity twice the rated power of the engine for several minutes. The energy storage feature also permits automatic engine shutdown at times of low load demand, with automatic startup when the load increases. The effect of the microprocessor control system is that it optimises engine operation according to the load demand, and produces a constant voltage and frequency output suitable for sensitive modern electronic appliances (see Fig.2). It does so even under the most abusive load conditions with which conventional systems cannot cope without sustaining ultimately terminal engine damage.

	Fig 2: Hygen output voltage in worst-case load scenario The Hygen system achieves this operational efficacy with a low fuel consumption. Its energy storage feature and variable-speed operation avert the need for a fuel sapping dummy load to protect the engine against light loading, and fuel input is thus proportional to electrical power output. The effect of this is quite dramatic at low load levels (see Fig.3).

	Fig 3: Fuel economy for constant and variable speed operation The avoidance of light-loading reduces engine maintenance costs and extends engine life up to three times that of the engines used in conventional gensets, according to computer simulations. The system can be optimised for compactness and light weight where the user deems these features to be more important than economy of operation, which may well be the case in some defence operations. Options include self-diagnostics and remote control by PC. Origin of the technology VoltAmpere commenced business 28 years ago as a rewinding shop and went on to undertake maintenance, repair and remanufacturing work on a wide range of electrical machines. The company was fortunate to win a number of maintenance contracts for large fleets of gensets, amongst them that of the SA National Defence Force, including in field operations hundreds of kilometres from the nearest industrial facility. Company chairman Manuel da Ponte explains: "This work identified for us the inherent shortcomings of conventional gensets, and set us thinking how they could be overcome." A major problem identified was the constant-speed operation of the heavy duty diesel engines in use, which necessitated over-sizing the genset in order to cope with, amongst others, peak load conditions. Yet outside of peak consumption periods, demand averaged only 20-30% of maximum in a common load profile. The resultant light loading caused damage to engines due to oil dilution and carbon build-up. Where a dummy load was used to avert this cause of premature engine failure, the penalty was increased fuel consumption - vastly out of proportion to the energy output (see Fig.3). "A very poor trade-off," as Mr da Ponte put it. A further problem lay in output power fluctuations caused by the inability of the constant-speed gensets to respond to the peaks and spikes characteristic of real world load profiles. Fluctuating voltage and frequency might have been acceptable to the load devices of past generations - but not to today’s sensitive electronic appliances. The VoltAmpere engineers perceived that what was needed, in a remote bush camp for example, was a system capable of providing power in a scenario typically including workshop welders, water pumps starting up and other notorious voltage distorters kicking in without warning. It had to provide this without compromising the voltage quality for the modern computers, radar, communications and field hospital equipment on which the security and well-being of the camp relied. A tall order indeed! They accordingly embarked upon a seven-year research and development programme, culminating in the Hygen technology with worldwide patents. The Hygen system can be packaged to customers' specifications, similar to the packaging of conventional generator systems. Production Hygen systems at present come in 6, 12 and 24 kVA (single-phase) models, with larger models and diverse applications in the pipeline. They are currently hand manufactured in VoltAmpere’s Pretoria workshop, but plans are in hand for industrialisation and manufacture for the world market. However, regional production under licence is an option for negotiation where major defence users require manufacture within their own borders for strategic reasons. Mr Manuel da Ponte, VoltAmpere: Tel +27 12 328 6551 Fax +27 12 324 4203

		>>>>> e-mail >>>>> vanetcom@cis.co.za