The industrial power conversion to optimized functionality - Q&A with Karim Wassef, GE Energy Power Electronics

5With the demand for more robust, low-cost systems and greater computational capabilities increasing in industrial applications, power components are being required to deliver more voltage rails and tighter control of these rails. Karim describes important features that should characterize power modules used in industrial settings and explains the benefits of dedicating nonisolated point-of-load modules to specific functions in a distributed architecture.

IES: Briefly outline GE Energy Power Electronics’ technology and product inventory that supports industrial applications.

WASSEF: The industrial market’s embedded power needs are evolving to address greater computational capability. The market is seeing increased demand for digital processing in addition to the traditional analog loads common in industrial applications. Digital loads generally drive three main demands on power:

  • Lower output voltage rails (0.6 V to 2 V)
  • Many more voltage rails (10 or more on a single board)
  • Demand for tighter tolerance and control on the output voltage (set point accuracy, transient response, and so on)

The power sources, on the other hand, are still in the traditional industrial voltage range of 9 V to 36 V covering the most common voltages: 12 V, 24 V, 28 V, and 36 V. Some applications extend upwards to 60 Vin.

GE Power Electronics offers isolated and nonisolated standard board-mounted products to address this need. The Hammerhead series of isolated converters offers three families of products with an input range of 18 Vin to 75 Vin and output voltages at 3.3 V, 5 V, and 12 V:

  • EHHD: Eighth brick family based on the standard Distributed power Open Standards Alliance (DOSA) one-eighth brick at 75 W (shown in Figure 1)
  • KHHD: Sixteenth brick family based on the standard DOSA one-sixteenth brick at 50 W
  • SHHD: 1x1 brick family at 30 W

Figure 1: A GE Hammerhead series module based on the DOSA standard offers 18-75 Vin isolated.

This series offers direct power to analog loads down to 3.3 V and can double as intermediate bus voltage regulators that can be followed by any nonisolated product providing output down to 0.45 V.

The ProLynx nonisolated Point Of Load (POL) series of converters offers an input voltage range of 9 Vin to 36 Vin and a trimmable output voltage from 3 Vout to 18 Vout. ProLynx is available in 3 A and 5 A output.

The DLynx nonisolated POL series is designed to follow an intermediate bus converter and offers products from 3 A to 40 A available in both analog and digital versions. Digital versions allow I2C communication and control of the POL modules for optimum performance.

IES: What are the key requirements that designers should look for when selecting power sources for factory environments?

WASSEF: Factory automation is an interesting subset of the industrial market. Factory environments vary significantly. Some can be very well controlled and others can be extremely aggressive. For power modules, hostile environments can be characterized as thermally aggressive conditions or corrosive environments.

GE Power Electronics power modules excel at thermal derating. Our nonisolated POL modules provide full power under high temperatures without any airflow. The Hammerhead series is designed with a low profile on the top side for enabling direct contact cooling to a plate, thus simplifying implementation in small or enclosed spaces.

GE also promotes and participates in the creation of the quality standards set in IPC-9592A (Requirements for Power Conversion Devices for the Computer and Telecommunications Industries). IPC defines best practices and sets expectations for testing to provide product assurance across a broad range of requirements, including Highly Accelerated Life Testing (HALT), Highly Accelerated Stress Screening (HASS), Design Verification Testing (DVT), shock and vibration, environmental stress testing, corrosion, dust, solderability, Electrostatic Discharge (ESD), immunity, emissions, acoustic noise, and product safety, as well as recommend component derating guidance.

IES: Noise is a problem in some power-conversion applications. What products do you offer targeting noise reduction?

WASSEF: GE power modules are complete solutions that include all the required input and output filters needed to meet stringent application requirements with minimal external filtering. The Hammerhead series provides galvanic isolation between the primary and secondary sides. The transformer breaks the ground loop currents to significantly reduce noise. Attention to layout and the right combination of filter capacitances target other problematic noise sources such as the high-frequency switching slew rates associated with high-efficiency switches.

The nonisolated POL modules also allow frequency synchronization to simplify the filtering requirements external to the converters. GE also offers a series of board-mounted filter modules that can be matched to the power converters and suited to the customer’s application.

IES: What software tools and development aids do you provide for factory automation and industrial management projects?

WASSEF: GE offers a range of tools associated with our board-mounted power products. These include the power system designer tool, stability assessment tool, POL programming tool, tunable loop tool, and the new Digital Power Insight (DPI) suite (Figure 2) that allows direct communication with our latest generation of digital modules. These tools accelerate and simplify the implementation of GE’s digital power solutions.

Figure 2: The GE Digital Power Insight (DPI) kit enables USB direct communication with GE’s digital power modules.

IES: Looking ahead, what changes do you foresee in power-conversion technologies and applications for industrial designers?

WASSEF: As industrial applications continue to grow in complexity and power, the need for more robust, reliable, and lower-cost systems will continue to grow as well. This mirrors the evolutions in other market segments like communications, networking, and computing.

The basic implementation of one module for every conversion voltage from input to output has quickly migrated to a Distributed Power Architecture (DPA). The concept of DPA is basically that of functional separation. The best way to visualize this is to look at an octopus with many highly capable arms, or a human arm composed of one arm and multiple fingers. The human arm purposefully separates the functions of gross motion and power from the fine control required by the fingers. Likewise, bus converters provide isolation and POL converters offer fine control at the sensitive voltage rails. The bus also focuses on minimizing the impact of input transients (ride through, protection, and so on), and the POLs focus on rail transients with minimal deviation, as well as high-accuracy set points and output ripple. DPA offers lower cost, smaller size, and improved reliability.

With new control ICs and FPGA loads demanding more voltage rails and tighter control of these rails, the focused benefits of nonisolated POL modules are becoming all the more valuable.

Karim Wassef, MBA, PhD, is director of DC-DC product line management at GE Energy Power Electronics.

GE Energy

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