Core Equipment in the Smart Energy Era: Power Electronic Transformer Solution for Power Generation

I. Background and Demand

With the rapid increase in renewable energy adoption, traditional electromagnetic transformers struggle to meet modern grids’ demands for flexibility, efficiency, and intelligence. The volatility and intermittency of wind and solar power pose severe challenges to grid stability, necessitating an innovative energy conversion hub capable of dynamic regulation and high-quality power output.

II. Solution Overview

This solution employs all-solid-state Power Electronic Transformers (PETs) to replace conventional line-frequency transformers. Leveraging high-frequency power electronics, PETs enable voltage-level conversion and energy control with core advantages:

• Flexible Power Conversion: Breaks the limitations of traditional transformers (voltage/current amplitude only) to achieve multi-dimensional control over frequency, phase, and power.

• Dynamic Response: Millisecond-level adjustment speed effectively mitigates renewable energy fluctuations.

• Smart Interface: Creates a digital bridge between power generation units and the grid.

III. Core Technical Architecture

1. Multi-Level Topology Optimization

Adopts an "AC-DC-AC" Three-Stage Conversion Architecture:

• High-Frequency Rectification Stage: Uses MMC (Modular Multilevel Converter) topology to accommodate wide input voltage fluctuations.

• Isolated DC-DC Stage: Implements Dual Active Bridge (DAB) structure for 10-20 kHz high-frequency isolation.

• Smart Inversion Stage: Supports dynamic switching of grid-tie strategies (V/f control, PQ control).

2. Key Component Selection

3. Intelligent Control System

Real-time grid status monitoring enables:

• Active voltage sag ride-through (LVRT/ZVRT)

• Dynamic power flow adjustment for renewable fluctuations

• Loss optimization algorithms

IV. Key Benefits and Value

Efficiency Gains

Functional Capabilities

• Active Filtering: Suppresses 5th&ndash;50th harmonics (THD <1.5%)

• Reactive Compensation: &plusmn;100% continuous capacity regulation

• Fault Ride-Through: Zero-voltage ride-through (ZVRT) support

• Black Start: Autonomous voltage/frequency stabilization in islanded mode

V. Application Scenarios

Scenario 1: Wind Farm Collector System

graph TB 

    WTG1[WTG1] --> PET1[10kV/35kV PET] 

    WTG2[WTG2] --> PET1 

    ... 

    PET1 -->|35kV DC Bus| Collector 

    Collector --> G[220kV Main Trafo] 

• Solves: Collector line oscillations from cumulative turbine voltage swings

• Results: 12% lower wind curtailment, 65% reduction in power fluctuation deviation

Scenario 2: PV Plant Smart Step-Up Station

• Modular PET clusters (1&ndash;2 MW/unit)

• MPPT functionality enhances yield by 7&ndash;15% in partial shading

• Nighttime operation as STATCOM for grid reactive support

VI. Implementation Roadmap

1. Pilot Phase: Deploy PETs at renewables plants with >10% voltage volatility (20% capacity).

2. Hybrid Grid Stage: Hybrid Transformer System (HTS) with parallel PET-traditional operation.

3. Full Replacement: PETs for all new projects; phased retrofits for existing plants.

VII. Economic Analysis

Example: 100MW Wind Farm

Conclusion: PET solutions break traditional electromagnetic limitations, creating a next-generation power conversion platform for high-renewable grids. Their advantages in efficiency, grid support, and intelligence position them as a strategic technology for modern power systems.