ALSTOM ALSPA series frequency converter

ALSPA Transmission Full Series: Industrial Drive Solutions from Low Voltage to 100MW

In the field of industrial transmission, the reliability, efficiency, and adaptability of the drive system directly determine the production capacity and energy consumption of the production line. ALSTOM (now under GE Power Conversion), with over 100 years of experience in transmission power devices, has been recognized as one of the industry leaders. Its ALSPA transmission product line covers from simple offline low-voltage inverters of 0.25kW to engineering customized drive systems of over 100MW. This article systematically reviews the product architecture, core controller technology, typical application scenarios, and global service system of the ALSPA transmission series from the perspective of a technical engineer, providing in-depth reference for professionals engaged in drive system selection, integration, and operation.

The history and technological accumulation of ALSTOM's transmission business

The foundation of ALSTOM in the field of transmission can be traced back to the early stages of electrification over a century ago. The company not only has advanced manufacturing factories in France, Germany, the United Kingdom, and the United States, but more importantly, ALSTOM integrates its own transmission products into other equipment and systems it manufactures (such as ship propulsion, traction power supply, and generator sets), thus accumulating decades of real user side operating experience. This dual mode of "self use+export" ensures that the product fully considers thermal stress, harmonics, impact loads, and maintenance convenience in actual working conditions during the design phase.

In recent years, ALSTOM has launched multiple innovative achievements in the field of driving solutions, including:

Marine pod type electric propulsion system (motor installed under the cabin)

19MVA, 4.2kV IGBT propulsion converter and motor for naval warships

100MVA inverter for pumped storage power station

15MVA, 50Hz three-phase to single-phase traction power converter equipped with active energy management

The technological accumulation of these high-end projects is directly fed back into the ALSPA standard products and engineering driver series, enabling industrial users to enjoy topology structures and control algorithms validated under extreme working conditions.

Overview of the full spectrum of ALSPA transmission product line

The ALSPA series is not a single product, but a complete family that covers voltage levels, power ranges, and motor types. According to the degree of standardization, it can be divided into two categories: standard equipment and engineering customized equipment.

2.1 Standard Equipment

Standard equipment refers to catalog selection products with short delivery cycles and mature spare parts support.

DC transmission: power range from 7.5kW to 25MW, customized solutions are available for 750kW and above. DC transmission is still suitable for applications that require high overload capacity and four quadrant operation, such as steel mills and mine hoists.

Low voltage AC drive (induction motor): 0.25kVA to 5MVA, suitable for common low voltage power grids such as 400V/690V. Typical applications include fans, pumps, compressors, extruders, and mixers.

Medium voltage AC drive (induction motor): 300kVA to 25MVA, output can directly reach 10kV without the need for a transformer. Suitable for medium voltage motors such as cement mills, crushers, large conveyors, and mining fans.

Synchronous motor or wound rotor motor drive: 0.25kW to 100MVA, supporting excitation control and slip ring control, used for high-power rolling mills, ship propulsion, wind tunnel drive, etc.

2.2 Engineering customized equipment

For special requirements beyond the standard product range, ALSTOM provides fully engineered drive systems, such as:

High power DC power supply and high current rectification system (used for electrolysis and arc furnaces), with a bridge arm of over 60000A per 12 pulses, based on direct water-cooled thyristor cabinets. A typical aluminum electrolysis factory configuration is 4 × 60kA or 5 × 70kA, 1000Vdc.

Static frequency converter (up to 100MVA), used for large magnet power supply (such as fusion research institutions) or AC/AC frequency conversion (three-phase/single-phase, 50Hz/16.7Hz, etc.), has provided a turnkey system for German railways from 110kV/50Hz to 25kV/16.7Hz.

Power Semiconductor and Control Platform: PEC Controller Family

In order to meet the control needs from simple single machine to complex multi transmission, ALSTOM has developed a new family of power electronic controllers (PEC). This platform covers from single card units (standard or advanced versions) to modular rack mounted systems, and can adapt to all ALSPA transmission products.

3.1 Advantages of Unified Architecture

The PEC family adopts a single architecture, and all core functions are implemented through common technologies:

Processor: Pentium class 32-bit floating-point arithmetic processor (optional DSP for some enhanced versions).

Operating System: A unified real-time operating system used for both transmission and automation control.

Programming standard: IEC 61131-3, core language is Function Block Diagram (FBD), also supports ladder diagrams, structured text, etc. This significantly reduces the programming barrier between PLC and transmission.

Control structure: Built on a universal functional block library, the same algorithm library can be used for low and medium voltage drives.

Programming tools: A unified engineering software environment that eliminates the need to switch tools between different product lines.

Human Machine Interface: A universal HMI system, including Drive Data Manager ™ Keyboard, PC visualization software, or central programming console.

Communication interface: Supports all mainstream fieldbuses, including WorldFIP, Profibus, Interbus, Ethernet, etc.

3.2 Flexible Expansion and Diagnostic Capability

PEC controllers offer optional enhancement features:

Enhanced processors (Pentium class or DSP) are used for complex control algorithms such as model predictive control or high-speed signal processing.

Scalable user I/O points.

Fieldbus option module.

In terms of diagnosis, due to the complete integration of the entire controller family, the diagnostic function has been significantly enhanced:

History: Extremely powerful and flexible event recording, supporting post fault analysis. The data can be exported to a common file format (such as CSV) for third-party tools (such as MATLAB, Excel) to analyze.

Status monitoring: Comprehensive alarm, trip, and user-defined event monitoring.

Remote diagnosis/remote maintenance: supports remote access through modems or Ethernet, reducing on-site service time.

Diagnostic data can be viewed or extracted using any of the following tools:

Drive Data Manager ™ Keyboard (handheld terminal)

PC based visualization software package

Central programming console for large-scale systems

Key points for selection and configuration of low-voltage AC transmission

Although the document does not list specific low-voltage series models (such as the previous ALSPA MV3000, VD4000, etc.), typical characteristics of low-voltage transmission can be extracted from the technical description:

4.1 Power coverage and voltage level

Low voltage transmission covers 0.25kVA to 5MVA. For loads exceeding 500kW, multi module parallel connection or high output current design is usually adopted. The input voltage is generally 380-480V or 690V, 50/60Hz.

4.2 Control mode

Low voltage transmission support based on PEC platform:

V/f control (for multi motor parallel connection or fan pump type)

Speed sensorless vector control (for high dynamic response)

Closed loop vector control with encoder (for positioning and constant torque load)

4.3 Typical Applications

The applications listed in the document include: cement mills, crushers, compressors, conveyors, cranes, extruders, mixers, fans, pumps, machine tools, marine propulsion, metal rolling mills, mine hoists, paper machines, presses, process production lines, dynamometers, test benches, wind tunnels, and wind turbines.

For system integrators, ALSTOM also offers low-voltage drive modules, inverters, and rectifiers (up to 3.6MW) for easy integration into custom cabinets.

Medium voltage AC transmission: direct output without transformer

Medium voltage transmission is a major highlight of the ALSPA series. Traditional medium voltage frequency converters often require input transformers and output boost transformers, while some medium voltage solutions from ALSTOM can directly output up to 10kV voltage without the need for output transformers, significantly reducing system losses and footprint.

5.1 Technical Topology

Medium voltage transmission usually adopts unit series multilevel (such as perfect harmonic free) or neutral point clamped three-level topology. ALSTOM has extensive engineering experience in this field, particularly in the control of synchronous motors and wound rotor motors.

5.2 Performance advantages

High input power factor, no need for separate reactive power compensation device.

Output sine wave voltage without additional stress on motor insulation, allowing the use of ordinary medium voltage motors.

It can achieve energy feedback (four quadrant operation) and is used for loading mine hoists or centrifuges.

5.3 Selection considerations

When choosing medium voltage transmission, users should pay special attention to:

Motor type: induction motor, synchronous motor, or wound rotor motor. Synchronous motors require excitation control units, and ALSTOM provides complete excitation system integration.

Overload capacity: usually 110% continuous, 150% per minute.

Environmental conditions: The medium voltage transmission cabinet is usually IP42 or IP54, and heat dissipation (water cooling or forced air cooling) needs to be considered.

DC drive and special power supply

Although AC transmission has become mainstream, DC transmission still holds an irreplaceable position in some high overload, large inertia loads, or old renovation projects.

6.1 DC drive specifications

ALSPA DC transmission covers 7.5kW to 25MW, with standard products below 750kW and engineering customization above. Adopting 6-pulse, 12 pulse, or 24 pulse rectification, with optional harmonic filters. Suitable for:

Rolling mill (reversible rolling requires four quadrant operation)

Mine hoist (potential load, regenerative energy feedback to the power grid)

Plastic extruder (constant torque, low speed, high current)

6.2 High current rectification system

For applications such as electrolysis and electric arc furnaces that require tens of thousands of amperes of direct current, ALSTOM provides direct water-cooled thyristor cabinets. For example, aluminum electrolysis plants typically require a power supply of 4 × 60kA or 5 × 70kA, 1000Vdc. Every 12 pulse bridge arms can provide over 60000A of current, with a large number of successful operational achievements worldwide.

6.3 Static Var Compensation (SVC)

ALSPA also offers the PQS series static reactive power compensation system for flicker compensation and power factor correction in electric arc furnaces. This belongs to the power quality solution and is often supplied in conjunction with the transmission system.

System Integration and Project Management Services

ALSTOM not only provides driver components, but also offers complete system design and engineering services, including:

Automation system integration (PLC, DCS interface)

Full project general contracting management (from conceptual design to commissioning and delivery)

Manufacturing of large motors and generators (supplied in conjunction with transmission)

For system integrators, ALSTOM can provide "white label" driver modules to help integrators build their own brand of driver solutions. This includes low-voltage modules, inverters, rectifiers, with a maximum capacity of 3.6MW.

Global Service and Lifecycle Support

ALSTOM's service philosophy is that customer relationships truly begin when the system is put into operation. Its global service network covers all continents and provides the following support:

8.1 Basic Services

24-hour telephone hotline

Emergency fault on-site response

Remote diagnostic facility (connected to the driver controller via modem or VPN)

Service and Maintenance Contract (Regular Inspection, Preventive Maintenance)

8.2 Spare Parts and Outdated Management

Spare parts supply and inventory management (including consignment warehouses)

Outdated management plan: When a certain model is discontinued, provide an upgrade path or alternative solution to avoid users being forced to make unplanned modifications.

8.3 Training and Optimization

Training Center (covering operation, maintenance, and advanced programming)

Maintenance engineering (providing status monitoring and life assessment)

Factory and system optimization (energy efficiency audit, process improvement)

Upgrades and enhancements (such as converting old DC drives to AC drives, or upgrading control platforms to PEC)

How to Choose ALSPA Transmission: Engineer Decision Framework

In practical projects, facing such a broad product line of ALSPA, it is recommended to screen according to the following steps:

Determine motor type and power: induction motor or synchronous/wound rotor? Does the power exceed 5MVA? If exceeded, it is necessary to enter the medium voltage transmission selection.

Determine voltage level: Is the current grid voltage low voltage (≤ 690V) or medium voltage (2.3kV-13.8kV)? Medium voltage transmission can choose models without output transformers to save investment.

Determine operating quadrant: Is it necessary to operate in four quadrants (regenerative power generation)? If necessary, choose a rectifier unit with energy feedback (such as AFE).

Control performance requirements: Ordinary fans and pumps can choose V/f control; High dynamic response (such as cranes and rolling mills) requires closed-loop vector control and may require encoder interfaces.

Communication and automation integration: Confirm the fieldbus types (Profibus, Modbus TCP, EtherNet/IP, etc.), and the PEC platform supports almost all of them.

Environment and Services: Is it located in a remote area? Need to assess the coverage level of the local service network. ALSTOM has core centers in France, Germany, the United Kingdom, and the United States, but covers the globe through partnerships.

Common technical problems and troubleshooting ideas (based on PEC platform)

10.1 No display after power on transmission

Check if the control power supply (usually 24Vdc or 110Vac) is functioning properly.

Check the fuses or power modules of the PEC control board.

Using Drive Data Manager ™ Keyboard attempts to connect, if the keyboard displays but the HMI does not display, it may be a backlight or LCD cable issue.

10.2 The motor does not rotate but there is no fault code

Check if the startup command (DI or communication) is activated.

Check if the speed setpoint is zero or below the minimum speed.

Check the "Enable" and "Run" bits in the status word. The PEC platform can monitor the input and output of functional blocks online.

10.3 Overcurrent tripping

Check the insulation of the motor and whether there is a short circuit to ground in the cables.

Check if the acceleration time is too short, causing a current spike.

For vector control, check if the motor parameter self-tuning is complete. ALSPA transmission typically supports static and dynamic identification.

10.4 Historical record analysis

After the malfunction occurs, connect to the transmission using PC software and export the historical record file. Due to the universal data format, it can be imported into Excel for trend chart analysis or sent to ALSTOM remote diagnostic center.

10.5 Interruption of fieldbus communication

Check the terminal resistance of the bus cable (if Profibus needs to be activated at both ends).

Check the status LED of the PEC communication card.

Use a bus monitor (such as Wireshark for Ethernet) to capture messages and confirm whether the master station sends data periodically.

Comparison and positioning with competing products

Characteristics: ALSPA Transmission, Mainstream European and American Brands, Mainstream Japanese Brands

Low voltage power upper limit 5MVA, usually 2-3MW, usually within 1MW

Medium voltage power upper limit>100MW (engineering) can reach up to 50MW, which is relatively small

Controller platform unified PEC (32-bit floating point), different series, different series

Programming language IEC 61131-3 (FBD) specific language or Codesys specific software

High current DC power supply above 60kA with minimal water cooling

Our global service has a wide range of proprietary networks, mainly in Asia

The differentiated advantages of ALSPA lie in ultra-high power (100MW level), high current rectification, and diagnostic and programming consistency brought by a unified PEC platform. This is particularly important for multi drive production lines such as papermaking and metallurgy.