In-depth Analysis of the Three Core Aspects of PV, ESS and Charging
What kind of sparks will fly when PV meets ESS (ESS) and then links up with EV Charging?
The integrated PV+ESS+EV Charging system is becoming a "super solution" to alleviate grid pressure and enhance energy efficiency. The integrated PV+ESS+EV Charging system consists of a small microgrid system consisting of distributed PV power sources, ESSs, charging and discharging control devices, and distribution facilities. It organically integrates the three major technical modules: PV power generation, energy storage buffering, and intelligent charging. This article will conduct an in-depth analysis of the three core components of this system, unveiling how they operate in harmony, much like precisely meshed gears, to construct a clean, efficient, and intelligent energy future.
- PV Power Generation System
- Core function: Through the semiconductor materials in PV panels, solar energy is efficiently converted into clean electricity, laying the energy foundation for the entire system.
- Technical analysis: PV systems can be divided into grid-connected and independent types. The grid-connected system is primarily composed of key components such as PV panels, supporting structures, cables and grid-connected inverters. Its defining feature is that the generated electricity is directly fed into the public power grid . In contrast, the off-grid system incorporates battery packs and charge-discharge controllers in addition to the components of the grid-connected system, enabling autonomous electricity storage and utilization.
The fundamental difference between the two systems lies in presence or absence of an energy storage device. Throughout the energy conversion process, the PV module first first transforms solar energy into direct current (DC), which is then converted by the inverter into alternating current (AC) that meets grid standards. This power conversion mechanism constitutes the basic principle of PV power generation technology .
- ESS
- Core role: The the ESS’s core function is to enable the temporal and spatial transfer of electrical energy, effectively resolving the mismatch between power generation and consumption.
- Technical analysis: The working principle of the ESS can be vividly likened to that of a "giant power bank", which stores the excess electricity generated by PV power generation through a battery pack and releases it during peak electricity demand periods. When PV power generation exceeds immediate needs, the ESS enters the charging mode . Conversely, when electricity demand surges or photovoltaic power generation is insufficient, it switches to the discharging mode , converting the stored energy back into electrical output. This "low storage, high release" operating mode not only achieves peak load shaving and valley filling, but also allows for benefits from peak-valley electricity price differences through participation in electricity market transactions. Additionally, it mitigates user-side supply-demand contradictions, reduces power generation equipment investment, boosts power equipment utilization rates, and minimizes line losses.
- Charging System
- Core role:
As the terminal link in the integrated photovoltaic storage and charging solution, the charging system's core role is to achieve efficient distribution and intelligent scheduling of electrical energy.
- Technical analysis:
The PV power station mainly operates on the principle of grid-connected PV power generation system. The electrical energy converted from solar energy by PV modules is not only transferred to the battery for storage via the PV charging controller, but also transmitted to the grid through the grid-connected inverter. In this way, part of the electrical energy is used to charge EVs, while the other part is inverted and fed into the grid. In addition, PV power stations can also serve as backup power sources for highway service areas.
When the monitoring unit in the system detects a grid failure and power outage, it can quickly disconnect t the system from the power grid and immediately activate the inverter for off-grid power supply. When the grid recovers from the fault, the system can switch to normal working state.
- Five Energy Circuits
Detailed explanation of the five major circuits
- Circuit 1
To realize the role of energy storage for PV power generation: The DC converted from solar energy is stored in the battery pack through the intelligent controller
- Circuit 2
To achieve the function of inverter grid connection of battery pack in ESS: The electrical energy stored in the battery pack in the ESS is converted into AC by an inverter and then fed into the power grid.
- Circuit 3
This circuit achieves the grid-connected power generation of the photovoltaic system. The DC power generated by the PV module is inverted and then fed into the grid. If there is surplus PV power, it can be sold to the grid through this circuit to generate economic benefits. Note that the inverters in Circuits 2 and 3 are shared, so these two circuits cannot operate simultaneously.
- Circuit 4
It realizes the ESS’s power feeding: the energy storage power is fed into the grid through two-stage conversion (DC/DC and DC/AC), serving as a backup power supply circuit when the main inverter is occupied. When Circuit 3 is activated, the power stored in the battery pack can be fed into the grid through Circuit 4.
- Circuit 5
This circuit enables the mains charging function. When the grid electricity price is lower than the average grid electricity price, the ESS can draw electricity from the grid through Circuit 5 to charge itself, capitalizing on the price difference.
With technological advancements and supportive policies, the PV-ESS-Charging model is destined to become an integral part of the new power system, providing robust support for the realization of carbon neutrality goals. Let us eagerly anticipate this green energy solution shining more brilliantly in the future.
