Hệ Hybrid & InverterHybrid & inverter · BàiLesson 1/9
Operating Principles of the Hybrid Inverter
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Solar Knowledge HubNguyên lý biến tần HybridHybrid inverter principles
Biến tần Hybrid gộp ba việc trong một thiết bị: bộ sạc điện mặt trời, bộ sạc/xả pin hai chiều và bộ đổi DC→AC, điều phối tấm pin, pin, lưới và tải cùng lúc.A hybrid inverter combines three jobs in one: solar charger, bidirectional battery stage, and DC-to-AC converter, managing panels, battery, grid, and load together.
| Tình huốngSituation | Hành vi của hệSystem behaviour |
|---|---|
| Ban ngày nắng tốtDaytime, good sun | Điện mặt trời cấp tải → dư sạc pin → đầy thì có thể hòa lướiSolar to load → surplus charges battery → if full, may export to grid |
| Ban đêm có pinNight, battery available | Pin cấp tải; nếu pin yếu mới lấy thêm điện từ lưới bùBattery to load; only when battery weak does system draw from grid |
| Mất điện lướiGrid outage | Chạy độc lập: pin + điện mặt trời cấp tải qua cổng dự phòngStandalone: battery + solar to loads via backup port |
| Ưu tiên tự dùngSelf-consumption priority | Ưu tiên điện mặt trời và pin, thiếu mới lấy lướiSolar and battery first; grid only when short |
Bản gốc ghi "ưu tiên lấy điện từ lưới để bù đắp cho tải" ở chế độ ban đêm: sai nghĩa. Câu đúng là "nếu pin yếu, hệ mới lấy điện từ lưới để bù". Hệ Hybrid không ưu tiên lưới vào ban đêm.The original stated "prioritise drawing from grid to compensate load" at night: wrong. The correct behaviour: "only when battery is weak" does the system draw from the grid. Hybrid does not prioritise the grid at night.
Phân biệt nhanh: nhìn đồng hồ điện và thiết bị. Nhà chỉ có một pha 220V → chọn hệ một pha. Nhà/xưởng có ba pha 380V và thiết bị ba pha → chọn hệ ba pha. Đừng tư vấn hệ ba pha cho nhà chỉ có một pha.Quick guide: check the meter and appliances. Home with only single-phase 220V → single-phase system. Site with three-phase 380V and three-phase equipment → three-phase. Never recommend three-phase for a single-phase home.
Understanding what sets a hybrid inverter apart from a conventional inverter (and how it coordinates four energy sources: solar panels, battery storage, the grid, and loads simultaneously) is the foundation for selection and installation. This document explains those principles, distinguishes three system types, and differentiates single-phase from three-phase systems.
For: newcomers who need a foundation, technicians who need to understand operating modes, and sales staff who need to explain hybrid systems to customers.
Quick Summary
A hybrid inverter combines three functions in a single device: a solar charger, a bidirectional battery charge/discharge stage, and a DC-to-AC converter. This allows it to coordinate solar panels, battery, grid, and load all at once.
There are three system types. On-grid connects only to the grid, has no battery, and shuts down during a grid outage. Off-grid operates fully independently. Hybrid does both: self-consumption when the grid is present and backup when the grid fails.
The default energy priority is: solar supplies the load first, any surplus charges the battery, and the grid is drawn upon only when there is a shortfall. Single-phase systems suit residential homes; three-phase systems suit larger loads and can balance load across all three phases.
How a Hybrid Inverter Differs from a Conventional Inverter
A conventional grid-tie inverter does one thing: it converts DC from solar panels into AC to supply loads and the grid, and it shuts down during a grid outage for safety. A hybrid inverter adds two further capabilities: bidirectional battery charging and discharging, and the ability to run as an island to supply a backup load during a grid outage. As a result, it manages four simultaneous energy flows: solar panels, battery, grid, and load.
The three system types serve three distinct needs. On-grid is the simplest and least expensive, reducing daytime electricity bills but providing no power during an outage. Off-grid is fully independent, requires no grid connection, and needs larger panels and battery capacity. Hybrid sits in between (it grid-ties for self-consumption and backup while also storing energy), making it the most popular choice for homes and small businesses in Vietnam.
Operating Modes
Over the course of a day, a hybrid inverter transitions between several modes depending on solar irradiance and grid status.
During daytime with good sun, solar power supplies the load first; any surplus charges the battery, and if the battery is full the remaining surplus can be exported to the grid where permitted. At night, the battery supplies the load, and the system draws supplemental power from the grid only when the battery is low. During a grid outage, the system switches to island mode and supplies the backup load from the battery and solar panels through the backup port. In self-consumption priority mode, the system always prioritises solar and battery, drawing from the grid only when there is a genuine shortfall.
| Situation | System behaviour |
|---|---|
| Daytime, good sun | Solar supplies load; surplus charges battery; if full, may export to grid |
| Night, battery available | Battery supplies load; grid supplements only if battery is low |
| Grid outage | Island mode: battery and solar supply load via backup port |
| Self-consumption priority | Solar and battery prioritised; grid drawn only when insufficient |
The default energy priority order is therefore: solar first, then the in-home load, then battery charging, and finally grid export or grid import.
The original infographic’s description of night mode read “priority is to draw power from the grid to supplement the load,” omitting an important condition. The correct statement, per the source image, is “if the battery is low, the system draws power from the grid to supplement.” This is a significant technical distinction: a hybrid system does not prioritise the grid at night: it draws from the grid only once the battery is depleted, which is consistent with the self-consumption philosophy.
Single-Phase and Three-Phase Systems
The two configurations serve two different load scales. A single-phase hybrid system supplies single-phase 220 V loads found in homes: lighting, televisions, refrigerators, washing machines, air conditioners, and induction cooktops. Typical capacities range from 3 to 10 kW; installation is straightforward and costs are lower, making it suitable for townhouses and small villas.
A three-phase hybrid system supplies three-phase loads such as pumps, air compressors, central air conditioning, and EV chargers at 380 V as provided by the EVN grid, equivalent to 400 V under international standards. Typical capacities range from 5 to over 30 kW. The ability to balance load across all three phases provides greater stability for larger installations, making it appropriate for large villas and industrial premises.
A quick way to identify the right system for a customer is to look at their electricity meter and equipment. If the property has only single-phase 220 V power and standard household loads, choose a single-phase system. If the property has three-phase 380 V power and three-phase equipment such as large pumps or high-power EV chargers, choose a three-phase system. Do not recommend a three-phase system to a property that only has single-phase infrastructure, as it will not suit the existing electrical setup.
Hybrid system definition and the four operating modes per BSL Battery and Firstgreen Consulting. Energy priority order (solar, load, battery, grid) per inverter.com. On-grid / off-grid / hybrid distinction per SRNE and Clean Energy Reviews. Single-phase 220 V and three-phase 380 V EVN grid voltages, equivalent to 230 V and 400 V under IEC standards, per Power-Sonic and World Standards. Correction of the “if battery is low” condition in night mode per verification findings and Xindun.