Configuring for Power Density and Connectivity

­The availability of modular, configurable power supplies provides industrial and medical system designers with an approach to develop systems that address application-specific requirements without time and resource consuming custom design or compromising with less optimal standard, off-the-shelf solutions.

As the functionality and performance of industrial and medical systems continue to increase, so does the pressure on designers to deliver much higher density power architectures. At the same time, they are being asked to integrate IoT functionality into their systems to allow for remote, cloud-based monitoring and control. This fuels demand for more efficient and intelligent configurable solutions. Therefore, power supply manufacturers must develop new generations of configurable, efficient power supplies to take power density to new levels while providing extensive connectivity options.

More Performance, Higher Power, Less Space

Across all fields of electronic equipment manufacture, OEMs are facing the challenge of delivering higher density solutions with greater functionality. This is particularly true in higher power areas including medical electronics, industrial equipment and semiconductor manufacturing equipment. In these applications, several kilowatts of power may be required with a variety of standard and non-standard output voltages. What’s more, in some of these systems there may be a need for constant current outputs – for example, charging of batteries and/or capacitors or powering lasers that are increasingly being used for medical and cosmetic treatments.

Even when the equipment is large – like ‘big iron’ medical applications such as MRI scanners or industrial factory automation systems – the space available for the power supply can be constrained. This is especially prevalent when supplies must be located close to the load and can present designers with significant difficulties in delivering required power levels. As power supplies become smaller, the available surface area and volume for necessary cooling becomes reduced, while densely packed power supplies decrease the effectiveness of forced air cooling. Addressing these size/performance/power challenges demands higher levels of efficiency.

Configurable Power

It is easier to source power solutions with voltages commonly required to power logic and even common analog rails, as these solutions are readily available. However, medical, semiconductor and industrial applications often incorporate elements such as sensors that require non-standard voltages, which would require some form of a modified-standard (or even full custom) power supply.

While this is technically possible, there can be commercial drawbacks to a full-custom approach including development timescales, engineering costs and the ultimate per-unit cost of the solution. Unlike standard power supplies that have been designed for a specific market (e.g. medical), turnkey technologies have the potential to add time to the overall system certification process.

These factors have led some power supply manufacturers to offer modular (or ‘configurable’) power solutions that combine the flexibility of rapid configuration and support for rapid certification.

Typically, a modular power supply consists of a chassis with the front end of a power supply (PFC stage) and several different output modules, each of which may be adjusted over a wide range of output voltage. With this approach, multiple different output modules can be added to the chassis, building a custom power solution in seconds.

Apart from rapid configuration during development, there are also benefits to this approach when in service. If the end equipment is re-configured or a new feature added, an additional output module can be added or an existing one exchanged. Additionally, the failure of one output does not require the replacement of the whole power supply, as individual modules can be replaced during maintenance. Often this requires little more than a screwdriver, as modules simply slot in.

Set-up and Monitoring

Early configurable power supplies with adjustable output modules were usually set with a potentiometer, requiring a technician to adjust after installation. Some incorporated sense pins to allow the output to compensate for any voltage drops in the wiring.

A significant step forward was the introduction of digital control technologies (such as PMBus) that allow modules to be configured (and re-configured) without the need for tools. This also enabled the capability to monitor outputs (voltage, current and temperature). Data in these parameters provide valuable in-service system insights. For example, a rail consuming more current than normal could indicate an impending issue; detecting this early allows rectification before any expensive failure or system downtime.

Despite the flexibility of many of the output modules offered with configurable power supplies, some loads may require an unusually high level of voltage or current. Most output modules were galvanically isolated, meaning that they could be combined in series (for higher voltage) or parallel (for higher current).

Figure 1b

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Figures 1a 1b: Bus bars allow output modules to be combined in series or parallel

Most manufacturers offered bus bars as accessories to allow for connected modules in series or parallel. Although possible, not every module had to be connected in the same group. For larger supplies, it was perfectly acceptable to have multiple parallel/serial groups to meet the needs of the end application.

Certification and Time-to-Market

Certification is an essential aspect of power supplies to ensure that they are safe and suited to the application and environment that they will be required to operate in. When buying a standard off-the-shelf solution, designers prefer a certified power supply that can be immediately incorporated into their design.

However, if there is a requirement for a custom or modified-standard power supply then the degree of change required may necessitate re-certification by an external standards body. While there is some risk, a good design will normally pass, possibly with some tweaks. However, the process can increase costs and delay release to market by weeks, if not months.

As configurable power supplies are assembled from a standard chassis and standard output modules, they can be certified, provided the designer configures them in a manufacturer-approved way. Then, the certification remains valid and there is no delay in releasing the end product to market.

Latest Developments– Multi-Kilowatt Configurable Power

The power industry continues to advance in many areas, especially in server/datacenter applications where power density and performance are crucial. Advanced Energy has leveraged its expertise in this area to develop the high-density Artesyn® NeoPower, NP08, configurable power solution.

Capable of delivering up to 4 kW of power, the compact case consists of eight output modules with single-phase input from 90 to 264 VAC.

NeoPower offers the choice of voltage source or current source operation and is certified to medical standards (including Body Floating) and the semiconductor industry F47 standard for immunity to voltage sags.

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Figure 2: NeoPower NP08 offers 4 kW of power in a compact eight-slot chassis

All the modules have galvanically isolated outputs, to combine in series or parallel, and a range of bus bars are available for this purpose.

Communication options for monitoring and control are a fundamental element of the NeoPower range. The communication bus supports RS-485 (MOBUS RTU), PMBus and CANBUS (CANOPEN) protocols.

To further simplify monitoring and control, a graphical user interface (GUI) has been developed specifically for NeoPower, allowing easy access to all features and functionality.

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Figure 3: The advanced NeoPower GUI gives access to all features and functions

Summary

The benefits of configurable power apply to specialist applications that require non-standard voltages or unusual combinations of outputs. The configurable approach provides a method for designers to rapidly assemble a fully customized solution with all the required safety approvals.

NeoPower moves configurable power to the next level, providing up to 4 kW of power –and has an advanced IoT-based control and monitoring solution that ensures configurable power can cope with even the most demanding modern applications.

Advanced Energy