GE DC Drives (BCH series) upgrade and replacement of old DC drives

GE DC Drives (BCH series) upgrade and replacement of old DC drives

Introduction: The dilemma and necessity of upgrading old DC drives

In heavy industries such as metallurgy, papermaking, mining, lifting, plastics and rubber, a large number of DC drives have been running continuously for more than ten or even more than twenty years. These devices were once the heart of the production line, but over time, they are facing three fatal challenges:

Outdated platform and shortage of spare parts: The core boards (such as trigger boards and adjustment boards) have been discontinued by the original factory, and replacement parts are difficult to buy in the market. Maintenance can only rely on dismantling old machines or high imitation products, with extremely low reliability.

Specialized hardware and closed architecture: Old drivers use a large number of cables, custom connection boards, and application specific integrated circuits (ASICs). Once a non-standard component is damaged, the entire system may shut down for several weeks.

Difficulty in integrating with upper level control systems: Old drivers only support analog or dedicated protocols (such as GE's CIM and DCS link), which cannot integrate into modern open networks such as Ethernet/IP, Profinet, Modbus TCP, etc., resulting in data monitoring and automation upgrades being hindered.

In response to the above difficulties, the industry generally adopts two strategies:

Replacing the entire machine with an AC frequency converter: high cost, large engineering workload, need to replace the motor, and some high inertia loads (such as flying shears and coilers) still prefer DC drive.

Staged upgrade and renovation: retaining the existing power stack (thyristors, heat sinks, main circuit), only replacing the control part and trigger interface - this is the technical route that this article focuses on discussing.

This article will take GE Power Conversion's DC drive upgrade solution as an example to analyze in detail how to achieve non-destructive and phased replacement of old DC drive systems through open architecture, industrial computer controllers, and modern software platforms, significantly improving reliability and extending equipment life.

Overall upgrade strategy and advantages of open architecture

2.1 Core principles of upgrading and transformation

Successful DC driver upgrades should follow the following principles:

Maximize the retention of existing facilities such as power stacks, transformers, DC motors, and on-site cables for continued use.

Phased implementation: Upgrade a single key equipment (such as a coiler) first, validate it, and then promote it to avoid full line shutdown.

Open and scalable: The new control system must support multiple industrial Ethernet protocols and seamlessly integrate with PLC/DCS.

Simplify spare parts inventory: Use commercial off the shelf (COTS) components (such as industrial PCs, standard I/O modules) instead of customized boards.

2.2 Key Benefits of Open Architecture

The core of GE's solution lies in an open architecture, which has the following significant advantages compared to traditional closed DC drivers:

Characteristics: Traditional Closed Drive Open Architecture Upgrade Solution

Controller specific CPU board, discontinued standard industrial PC (PECe), Intel chip, can be independently replaced

Connection method: ribbon cable, customized harness without ribbon cable design, Ethernet, fiber optic, standard terminal

Network protocol proprietary protocols Modbus TCP, Profinet, EtherCAT, EGD, Profibus

I/O expansion fixed point or expensive expansion card third-party EtherCAT I/O, modular free combination

Software platform specific programmer, parameter obscure IEC 61131-3 functional block diagram, Windows environment, online simulation

After the original factory shutdown, the spare parts lifecycle is completely out of stock. Industrial PCs and standard I/O are available for long-term market supply

Key design highlights:

No wiring harness/dedicated wiring harness: Traditional drivers have multiple card boards connected by flat wiring harnesses, which can easily cause poor contact after vibration or oxidation. The GE solution completely eliminates these fault points through PECe controller+PIBe interface board+EtherCAT bus.

Retain the original power stack: Existing GE or third-party thyristor bridges, heat sinks, fuses, and reactors can continue to be used, with only the control part replaced, saving more than 60% of renovation costs.

Detailed explanation of core hardware components

The hardware of the upgraded system consists of four main parts: PECe controller, PIBe power interface board, EtherCAT field I/O, and human-machine interface.

3.1 PECe - The Brain of Drivers

PECe (Power Electronics Controller) is a reinforced industrial computer designed specifically for harsh electrical environments.

Key parameters:

Processor: Intel chip, 1.2~2.5 GHz, supports dual core/quad core

Operating system: Real time operating system VxWorks, ensuring deterministic response (μ s level)

Working temperature: 0~60 ° C, fanless design (maintenance free)

Ethernet interface: 5 10/100 Mbps ports for network control, debugging, and synchronization