Micro-arc Oxidation MAO – 750V 100A Industrial-Grade High Frequency Rectifier

EXECUTIVE SUMMARY
For surface engineers processing aluminum, magnesium, or titanium alloys, achieving a dense, high-voltage ceramic layer requires a power source that can sustain micro-arc discharges without voltage sag or waveform distortion. This 75kW unit is an industrial high frequency rectifier factory built specifically for the high-impedance, dynamic load of MAO plasma electrolytic oxidation PEO. Operating from a zero-start to a full 800V output, it delivers the consistent arc ignition necessary for coating thicknesses exceeding 200µm and micro-hardness values above 2000 HV. Rather than a general-purpose unit, this is a specialized anodizing rectifier that replaces bulky, inefficient SCR systems with clean, IGBT-switched DC power.
PART 1 KEY FEATURES & ENGINEERING HIGHLIGHTS
Constant Voltage / Constant Current Dual-Mode Regulation. The IGBT inverter technology provides a rapid response (<1ms) to the fluctuating plasma resistance during the MAO process, preventing the arc from extinguishing or transitioning to a destructive spark. This is critical for magnesium alloy ceramic coating, where voltage stability directly correlates to coating uniformity.
Heavy-Duty Thermal Management. Designed for continuous 24/7 operation in industrial environments, this unit features forced air or optional liquid cooling. The 100A current rating is deliverable even with ambient temperatures up to 50°C, ensuring uptime for production lines with concentrated load cycles.
Dual-Pulse Capability. The integrated pulse function (1Hz to 3000Hz adjustable) allows for the superposition of a high-frequency AC component onto the DC output. This is proven to densify the oxide layer on titanium bio-compatible oxide surfaces and reduce the energy consumption per µm of coating. To get the best heavy-duty DC power supply price for your specific pulse duty cycle, contact our sales engineers.
PART 2 TECHNICAL SPECIFICATIONS TABLE
| Parameter | Specification |
| — | — |
| Input Voltage | 3-Phase 380VAC ±10%, 50/60Hz |
| Rated Output Power | 75kW |
| Output Voltage Range | 0 – 750VDC (Continuous) |
| Output Current Range | 0 – 100ADC (Continuous) |
| Regulation Mode | Constant Voltage (CV) / Constant Current (CC) |
| Voltage Ripple | < 3% at rated load |
| Pulse Frequency Range | 1 – 3000Hz (Adjustable) |
| Duty Cycle | 10% – 90% (Adjustable) |
| Efficiency | ≥ 92% at full load |
| Communication Interface | RS485 Modbus RTU, Ethernet, 4-20mA Analog |
| Cooling Method | Forced Air (Liquid Cooling Optional) |
| Protection Class | IP20 (Indoor use) |
PART 3 ADVANCED BUILT-IN PROTECTION SYSTEMS
The system is engineered to safeguard the workpiece and the rectifier itself from the harsh electrical environment of an MAO bath. It includes:
– Short Circuit Protection: Instantaneous shutdown prevents damage to the IGBT modules and the ceramic layer being formed.
– Overvoltage & Overcurrent Limiting: Hard-clamping avoids exceeding the specified 750V or 100A thresholds even during load transients.
– Reverse Polarity Protection: Prevents connection errors that could damage the workpiece or the rectifier output stage.
– Thermal Overload Protection: Derating circuit reduces output current if internal heatsink temperatures exceed safe limits, avoiding forced shutdown.
– Arc Fault Detection: Monitors for sustained, high-energy arcing that can burn the workpiece, triggering a protective stop cycle.
PART 4 TARGET INDUSTRIAL APPLICATIONS
This rectifier is primarily designed for the anodic oxidation of light metals. Key processes include:
– Micro-arc Oxidation MAO of aluminum alloys for automotive, aerospace, and defense parts
– Plasma electrolytic oxidation PEO of magnesium alloy ceramic coating for electronic housings and medical implants
– Titanium bio-compatible oxide formation for surgical instruments and orthopedic implants
– Surface activation prior to adhesive bonding or painting on mixed-metal components
– Low-voltage decorative anodizing requiring stable, high-current density
PART 5 CUSTOMIZATION AND TAILORED ENGINEERING SERVICES
As an IGBT rectifier manufacturer, we understand that standard off-the-shelf units rarely fit the exact profile of a production line. We offer full customization on a custom current voltage rectifier basis:
– Output Range: 1V to 1000V, 1A to 100,000A (any combination within power limits)
– Input Options: Single-phase or three-phase AC, 220V to 480V
– Process Control Modules: Process Timer (H:M:S), Multi-Stage Profile Control (up to 20 segments), Ampere-Minute Integrator (Ah counter)
– Output Options: Automatic Reverse Polarity (stripping cycle), Soft-Start Ramp (0-30 seconds), Pulse Function (1-3000Hz adjustable with separate on/off times)
– Interface Integration: RS485 Modbus RTU, Ethernet/IP, Profinet, 4-20mA, 0-10VDC analog signal
– Front Panel: Touch-screen HMI with real-time voltage/current curve logging, password-protected parameter locking
If your application requires a non-standard voltage, a specific pulse format, or integration into an existing MES system, we can deliver a fully engineered solution with a 12-month warranty and on-site commissioning support.