Power Management of Solar PV Battery Supercapacitor in DC Microgrid
- lms editor
- 3 hours ago
- 3 min read
🌞 Introduction to the DC Microgrid
A DC microgrid is an advanced and decentralized energy framework that integrates renewable energy sources with efficient storage systems to deliver stable and reliable power. Unlike traditional AC systems, a DC microgrid eliminates conversion losses and enables seamless integration of components such as solar photovoltaic (PV) systems, battery energy storage, and supercapacitor modules.
The proposed DC microgrid model is designed to maintain a constant DC bus voltage of 400 V, ensuring optimal power quality and continuity of supply even under varying solar irradiance conditions.
⚙️ System Components and Specifications
🔋 1. Solar PV System
Total Power Rating: 2000 W
Individual Panel Rating: 250 W
Open Circuit Voltage (Voc): 37.3 V
Voltage at Maximum Power Point (Vmpp): 30.7 V
Short Circuit Current (Isc): 8.66 A
Current at Maximum Power Point (Impp): 8.15 A
IV–PV Characteristics under Different Irradiance:
At 1000 W/m², the PV system delivers maximum power close to its rated capacity, with performance gradually reducing as irradiance decreases.
🔋 2. Battery Energy Storage System
Nominal Voltage: 220 V
Rated Capacity: 48 Ah
Initial State of Charge (SOC): 50%
The battery serves as the primary energy buffer, compensating for energy imbalances between the PV array and the load during low irradiance or sudden transients.
⚡ 3. Supercapacitor Module
Capacitance: 99.5 F
Rated Voltage: 300 V
Initial Voltage: 295 V
The supercapacitor provides fast dynamic support during transient events such as sudden drops in solar irradiance or rapid load fluctuations, ensuring system voltage stability.
🧠 Control Logic for Power Management
The hybrid DC microgrid employs voltage–current dual-loop control to regulate energy flow across the PV array, battery, and supercapacitor.
🔹 Solar PV Control
Connected to the DC bus via a boost converter.
Implements Incremental Conductance (INC) MPPT to track the maximum power point dynamically under variable irradiance.
Delivers maximum possible energy to maintain the DC bus voltage close to 400 V.
🔹 Battery and Supercapacitor Control
Both energy storage systems are connected to the DC bus through bidirectional converters, operating under a double-loop control scheme:
Outer Voltage Loop:
Compares actual DC bus voltage with the reference (400 V).
Processes the voltage error through a PI controller to generate reference current.
Inner Current Loop:
Compares the reference current with the measured current.
Adjusts the converter duty cycle through another PI controller, ensuring smooth charge–discharge transitions.
This dual-loop control architecture enables stable DC bus regulation, efficient energy sharing, and quick transient recovery.
🔍 Simulation Results and Performance Analysis
☀️ PV Voltage and Current Behavior
PV voltage remains stable around 245–250 V.
PV current varies proportionally with irradiance — around 8 A at 1000 W/m², decreasing as solar intensity drops.
⚡ DC Bus Voltage Stability
The DC bus voltage is maintained consistently at 400 V, despite variations in solar input or load changes.
🔋 Battery and Supercapacitor Dynamics
0–2 s: PV power exceeds load demand. Excess energy charges both the battery and the supercapacitor.
2–3 s: PV generation matches load power. Battery current remains nearly zero, and the supercapacitor stays neutral.
3–5 s: PV power drops below the load requirement. The battery discharges to supply the deficit, while the supercapacitor handles fast transients, ensuring uninterrupted power delivery.
💡 Load Conditions
The connected DC load remains constant at 1000 W, allowing clear observation of system response to changing solar irradiance.
🏁 Conclusion
The simulation effectively validates the coordinated power management of a hybrid Solar PV–Battery–Supercapacitor-based DC microgrid.Through Incremental Conductance MPPT and dual-loop converter control, the system maintains a stable DC bus voltage (400 V), even under fluctuating irradiance and load conditions.
The battery provides long-term energy balancing, while the supercapacitor ensures rapid compensation for transient fluctuations. Together, they enable efficient, reliable, and high-quality power delivery — making this hybrid configuration ideal for future renewable-based DC microgrids and smart energy systems.
Comments