| 1 | Full-Scale Back-to-Back Voltage-Source Inverter | Permanent-magnet synchronous generators, electrically excited synchronous generators, and high-power variable-speed turbines | Approximately 100% of generator rated power | About 1–4 kHz for medium- and high-power systems | AC/DC/AC converter with independent generator-side and grid-side control; usually based on a voltage-source converter | Excellent variable-speed operation, wide reactive-power control, strong harmonic management, and effective isolation of generator frequency from grid frequency | Higher converter cost, semiconductor losses, and thermal-management requirements because the entire generator output passes through the converter | Approximately 96–99% at rated load, depending on voltage level and power rating | Utility-scale onshore and offshore projects requiring broad grid-code compliance and advanced power control |
| 2 | Doubly-Fed Induction Generator Converter | Variable-speed wind turbines using a wound-rotor induction generator | Typically 25–35% of generator rated power | About 1–3 kHz, depending on rotor voltage and harmonic requirements | Back-to-back rotor-side converter and grid-side converter connected through a DC link; stator remains directly connected to the grid | Lower converter rating and cost than a full-scale converter; good variable-speed range and separate active/reactive-power control | Slip rings require maintenance; direct stator-grid coupling increases sensitivity to grid faults and voltage disturbances | Approximately 97–99% at rated operating conditions, including generator and converter losses | Projects prioritizing established variable-speed technology and lower converter capacity |
| 3 | Two-Level Voltage-Source Inverter | Small and medium wind turbines, auxiliary converters, and modular full-scale converter systems | From a few kilowatts to several megawatts per converter module | Approximately 2–10 kHz at lower power; lower values are common at high power | Six-switch bridge using pulse-width modulation, generally with an L, LC, or LCL filter | Simple structure, mature control methods, compact design, and comparatively low component count | Higher device voltage stress and greater filter requirements than multilevel topologies; common-mode voltage can require mitigation | Approximately 95–98.5%, depending on power level and switching frequency | Cost-sensitive buyers needing a proven architecture for low- and medium-power applications |
| 4 | Three-Level Neutral-Point-Clamped Inverter | Medium- and high-power wind-turbine converters and medium-voltage grid interfaces | Typically hundreds of kilowatts to several megawatts per converter section | Approximately 500 Hz–3 kHz | Three voltage levels reduce output voltage steps; neutral-point balancing is managed through modulation and control | Lower dv/dt, reduced harmonic distortion, lower semiconductor voltage stress, and improved suitability for medium-voltage operation | More switches and clamping components; neutral-point voltage balancing becomes an important control issue | Approximately 97–99% at rated load | Utility and industrial buyers seeking a balance between efficiency, harmonic performance, and engineering complexity |
| 5 | Three-Level T-Type Inverter | Low-voltage and medium-power full-scale wind converters | Usually tens of kilowatts to approximately 1–2 MW per power stage | Approximately 1–8 kHz | Three-level voltage-source topology using bidirectional clamping switches and pulse-width modulation | Lower conduction losses than some three-level alternatives at moderate output current, improved waveform quality, and reduced filter size | Switching-device stress and thermal distribution must be carefully managed; scaling to very high voltage and power is more challenging | Approximately 97–99% at rated load | Buyers requiring high efficiency and compact packaging in low-voltage or medium-power turbine systems |
| 6 | Modular Multilevel Converter | High-power offshore wind, medium-voltage grid connection, and HVDC collection or transmission systems | From several megawatts to hundreds of megawatts, depending on system configuration | Usually a few hundred hertz to approximately 1 kHz at the switching-device level | Multiple cascaded submodules synthesize a stepped voltage waveform; capacitor-voltage balancing is coordinated digitally | Very low harmonic distortion, high scalability, low device switching losses, and strong medium-voltage performance | Large number of power cells, complex control and protection, capacitor management, and higher system engineering cost | Approximately 98–99.5% at system level, depending on voltage and power rating | Large offshore and utility-scale buyers prioritizing scalability, power quality, and grid interconnection flexibility |
| 7 | Cascaded H-Bridge Multilevel Inverter | Medium-voltage wind converters and converter systems using isolated DC sources or separate power cells | From hundreds of kilowatts to multiple megawatts | Approximately 500 Hz–3 kHz per cell, depending on the number of levels | Series-connected H-bridge cells create multiple voltage levels; phase-shifted modulation is commonly used | High-quality output waveform, modular construction, lower voltage stress per cell, and reduced need for bulky filters | Requires multiple isolated or balanced DC sources, more components, and complex fault-management strategies | Approximately 97–99% at rated load | Projects with modular maintenance objectives and suitable isolated DC-link or cell-level power architectures |
| 8 | Current-Source Inverter | Specialized medium- and high-power wind systems where robust current control and regenerative operation are important | Typically hundreds of kilowatts to several megawatts | Generally lower than low-power voltage-source inverters; commonly hundreds of hertz to a few kilohertz | DC-link reactor maintains current; line-commutated or self-commutated variants may be used according to the design | High short-circuit tolerance, natural current limiting, and potentially robust operation at high power | Requires a large DC reactor, can produce more reactive-power demand in some configurations, and has less widespread wind-market adoption | Approximately 95–98.5%, depending on commutation method and system rating | Specialized buyers with experienced maintenance teams and applications favoring current-source characteristics |
| 9 | Direct Matrix Converter | Specialized variable-speed wind-turbine drive and generator-converter research or niche applications | Commonly from tens of kilowatts to several megawatts in specialized designs | Typically several kilohertz at lower power, with lower values used as power increases | Direct AC-to-AC conversion through bidirectional switches; no large energy-storage DC-link capacitor is required | Compact energy-storage stage, bidirectional power flow, controllable input power factor, and potentially high power density | Complex commutation and protection, limited voltage-transfer ratio, and greater sensitivity to grid disturbances than many DC-link converters | Approximately 95–98%, depending on switching strategy and filter design | Technology-focused buyers evaluating compact, high-power-density solutions for specialized turbine platforms |
| 10 | Grid-Forming Wind Inverter | Full-scale converter wind turbines connected to weak grids, isolated systems, or power networks with high inverter penetration | Usually the same power range as the underlying full-scale converter, from hundreds of kilowatts to multi-megawatt units | Determined by the underlying voltage-source topology; commonly hundreds of hertz to several kilohertz | Voltage-source control establishes an internal voltage angle and magnitude using virtual synchronous-machine, droop, or matching-control methods | Improved voltage and frequency support, black-start potential in suitable systems, and better stability contribution in weak-grid conditions | Requires advanced controls, careful energy-reserve management, and coordination with protection systems and neighboring converters | Approximately 96–99%, depending on the underlying converter topology and operating point | Grid operators and project developers facing weak-grid conditions, low short-circuit ratios, or high renewable penetration |
