Rockwell Automation AutoMax™ Distributed Power System

3. Communication driven hardware components

According to the power level, the hardware configuration of AC drivers can be divided into several main types:

SA500 driver: suitable for lower power (14-48 amperes). Its characteristic is compact structure, and the DC bus power supply can supply power to up to six AC power modules. The PMI function is integrated into the regulator board inside the power module, achieving high integration.

SA3000 medium power drive: suitable for the range of 70-240 amperes. Adopting a four slot PMI rack similar to DC drive, but the rightmost slot is equipped with an AC power technology module. The power module adopts advanced IGBT technology and pulse width modulation technology, with built-in comprehensive diagnostic functions.

SA3000 high-power drive: suitable for high current applications ranging from 534-1457 amperes. Adopting an eight slot PMI rack, parallel interface modules and up to three gate drive interface modules have been added to support parallel operation of multiple power units. The local power interface module is responsible for conditioning and isolating feedback signals from the power unit.

SA3100 drive: covering the range of 1 to 800 horsepower. Its uniqueness lies in the fact that the PMI regulator, as a replaceable modular circuit board component, is directly installed inside the power module, integrating the processor, power technology circuit, UDC interface, and Flex I/O interface, resulting in a more compact structure.

1567 Power Max ™ Drive: Targeting medium voltage applications (1500-5500 horsepower). This is a complex system that includes independent rectifier cabinets, inverter cabinets, PMI subsystems, AutoMax racks, and liquid cooling systems. Its inverter adopts a three-level topology structure based on GTO and neutral point clamping. The PMI subsystem includes an eight slot rack, power interface board, etc., designed specifically for high-voltage and high-power environments.

Software and Programming: AutoMax Programming Execution Environment

All DPS drivers share a unified software interface - AutoMax programming execution software, which is a graphical configuration and programming tool running in the Microsoft Windows environment. It makes complex drive parameter configuration intuitive, and engineers only need to fill in the corresponding parameters in the graphical form based on the nameplate data of the motor, power module, transformer, and feedback equipment to complete the basic configuration.

This software provides a complete offline programming application suite:

System configurator: used to define the hierarchical structure of systems, regions, and racks.

Rack Configurator: Used for virtual configuration of AutoMax racks, including inserting modules, setting networks, and configuring driver parameters.

Variable configurator: used to map variable names to I/O points or public memory addresses.

Task Manager: Used to create user applications, also known as "tasks".

DPS applications are developed in the AutoMax environment and support three types of tasks:

BASIC task: Run on the AutoMax processor for high-level control.

Control Block Task: Can run on AutoMax processors or UDC modules. The tasks used for UDC modules (known as UDC tasks) use a predefined set of control blocks specifically responsible for driving the outer loop control.

Ladder diagram logic task: runs on the AutoMax processor and is suitable for sequential logic control.

Each AutoMax rack supports up to 32 tasks, shared by processors and UDC modules. Among them, UDC tasks are the core of driver control, and each UDC module can run two independent tasks, each controlling a driver. These tasks exchange data with the AutoMax processor through dual port memory, achieving a perfect combination of high-level coordination and low-level control.

UDC/PMI Communication and System Operation

The interaction between UDC module and PMI is the key to real-time control of DPS. After power on connection, PMI will actively request and load its operating system from the UDC module. Afterwards, both parties establish a synchronized instruction feedback message loop:

Instruction message: At the end of each UDC task scanning cycle, it is sent by the UDC module to PMI. Contains instruction data, track data, and predefined variable values that undergo changes.

Feedback message: Sent by PMI to the UDC module before the start of each UDC task scanning cycle. Contains feedback data and track data that has changed since the last message.

This tight, high-speed fiber based synchronous communication mechanism ensures high bandwidth and low latency of the control loop. The PMI operating system independently executes selected adjustment algorithms (such as vector control, V/Hz control, etc.) and continuously runs diagnostic programs to monitor temperature, DC bus voltage, ground current, IGBT overcurrent, and communication faults, achieving deep state monitoring and fault protection.

System Integration and Engineering Documentation

The deployment of DPS is accompanied by a complete set of standard engineering documents, namely the 'instruction manual'. This set of documents is provided after the equipment is shipped and serves as the cornerstone for equipment delivery records and subsequent maintenance. It typically includes: