Electrical Control Systems Specialist | Renewable Energy TVET Instructor | Bridging Control Systems Expertise with Renewable Energy innovations (💡)
Comparing Grid-following with Grid-forming inverter technologies .................................................................... • Grid-following inverter is also known as Current source inverter (CSI), while Grid-forming inverter is also referred to Voltage source inverter (VSI). ✅️ • Grid-following inverter is led by pre-existing strong grid, while Grid-forming forms grid by stabilising it with voltage and frequency for synchronization ✅️ • Grid-following inverter is synchronized with the grid using Phase-Locked Loop (PLL) control strategy, while Grid-forming inverter is synchronized with the grid using Droop control and virtual synchronous machine (VSM) ✅️ • Grid-following inverter will be non-existent if grid gets dead, while Grid-forming inverter can exist after the grid is dead (non-existent) using its islanding mode capability ✅️ • Grid-following inverter doesn't support isolated microgrid and mini-grid, distributed energy resources (DERs) becouse its reliance on existing grid electrical parameters (voltage, frequency), while Grid-forming inverter does aid isolated DERs with islanding capability by feeding local loads with no problem ✅️ • Grid-following inverter output stability depends on the grid's output stability, while Grid-forming inverter output stabilizes independently to local isolated loads ✅️ • Grid-following inverter is applicable to the regions of grid domination, while Grid-forming inverter is applicable to inverter-dominant regions ✅️ • Grid-following inverter works on PLL control architecture, while Grid-forming inverter operates with two control architectures: 1. Droop control architecture for Power- frequency deviations handles ✅️ 2. Virtual synchronous machine (VSM) control strategy for mimicking traditional synchronous generators with large rotating inertia and swing dynamics ✅️ • Grid-following technology is adopted widely in renewables, while Grid-forming technology is new promising technology with potential benefits to renewable industry ✅️ • Grid-following inverter is old version, while Grid-forming inverter is new, future-proof technology to the renewable energy industry. ✅️ □ Strategic implication: "the grid of the future will not be followed—it will be formed"
Electrical Control Systems Specialist | Renewable Energy TVET Instructor | Bridging Control Systems Expertise with Renewable Energy innovations (💡)
🔌 Grid-Following Inverters: The Technical Backbone of Modern Grids Grid-following inverters are the fundamental components enabling today's rapid integration of renewable energy sources. Their primary function is to act as a controlled current source, injecting power into the grid while strictly adhering to its existing conditions. The core of a grid-following inverter's operation is its ability to synchronize with the grid using a Phase-Locked Loop (PLL). The PLL ensures the inverter's output is perfectly aligned with the grid's voltage. This synchronization is captured by the relationship: Vgrid =Vm ⋅ cos(ωt+θ) [1] Here, Vm is the grid voltage magnitude, ω is the angular frequency, and θ is the phase angle, which the PLL tracks precisely. Based on this, the inverter's controller generates the current reference signals (Idref, Iqref) in a rotating reference frame (d-q frame) to control active and reactive power flow: ● Active Power (P): Controlled by the d-axis current. P = 3 ÷ 2 (Vd ⋅Id + Vq ⋅ Iq ) [2] ● Reactive Power (Q): Controlled by the q-axis current. Q = 3 ÷ 2 (Vq ⋅ Id −Vd ⋅ Iq ) [3] ● In grid-following mode, the inverter aligns its d-axis with the grid voltage vector, making Vq approximately zero. This simplifies the power equations to: P≈ 3 ÷ 2 (Vd ⋅ Id) [3] Q≈ - 3 ÷ 2 (Vd ⋅ Iq) [4] ● This allows for the independent control of active power (via Id ) and reactive power (via Iq), enabling the inverter to follow grid commands. ● Conclusion: While a highly effective strategy for today's centralized grids, grid-following inverters are dependent on a strong grid for stability. The rise of renewables is changing this, paving the way for #gridforming solutions that can create their own stable voltage and frequency. What are your thoughts on the future balance between grid-following and grid-forming technologies? 🤔 Will they coexist, or will one eventually dominate? #PowerElectronics #GridFollowing #RenewableEnergy #ElectricalEngineering #SmartGrid #PowerSystems #EnergyTransition