• Enhance self-consumption: During the day, the electricity from the PV array is used to optimize self-consumption. The excess power charges the batteries, whose power supplies the loads at night. By utilizing storage, the self-consumption can reach up to 95%.
• Benefit from peak shaving: By setting the charging and discharging time, the battery can be charged using the electricity generated at off-peak rates and discharged to fulfill the loads during peak hours (if the grid regulations allow it).
• Provide backup for critical loads: Connected to the backup side of the inverter, loads such as refrigerators, routers, lamps, computers and other critical appliances can be powered when the grid fails. The system can automatically switch to backup mode within 10 milliseconds.
System Wiring and Operation
The hybrid inverters are the core of the energy storage systems and they are integrated following elements into one unit: MPP trackers, power inverter, battery charging & discharging function, BMS communication & by-pass & backup function. GoodWe´s hybrid portfolio is a perfect fit for a great number of residential and small commercial scenarios.
There are three basic modes that end users can choose from the PV Master App.
• General Mode: At daytime, the power generated by the PV system is used in the following order: First, feed the home loads; second, charge the battery and third, export the surplus power to the grid. At night, the battery powers the loads. If the power supply from the batteries is not sufficient, the system is designed to switch automatically to the grid in order to keep the loads supplied.
• Backup Mode: Under this mode, the battery is only used as a backup power supply when the grid fails and as long as the grid works, the batteries won’t be used to power the loads. The battery will get charged with the power generated by the PV system or from the grid.
• Economic Mode: The customer is able to set the battery charging and discharging times according to the grid peak and off-peak tariffs and the household power consumption habits.
1.2 All in One System (ESA Series)
GoodWe is pleased to introduce the ESA Series, an "All-in-One” hybrid system that is designed to simplify the installation process to the maximum. It consists of the following elements: a hybrid inverter, a battery bank and a pre-wired system located inside a modern cabinet; it also includes connection devices and a preset cable slot. It is estimated that this system reduces the installation cost by as much as 60%!
• Pre-Installed Devices: Built-in DC switch, AC breaker (On-Grid/Backup), battery breaker, switch board, earth terminal and communication unit.
• Pre-Wired Design: The smart meter, the battery and the AC breaker are pre-wired and pre-connected at the factory and at the moment the set reaches the end users, it is ready to be deployed and installed.
• Preset Cable Slot: As part of the systems design, there is a cable slot, where external PV and CT cables to the grid or the loads can be placed.
• In addition, the ESA system is also equipped with an AC load bypass switch, used for switching the load supply from the backup to the grid; the bypass switch also performs the rapid shutdown protection through the connection of an additional external breaker with a switch board.
GoodWe Hybrid Portfolio
2. AC coupled retrofit solution
On-grid & backup function integrated
Converting on-grid systems into hybrid systems
2.1 Typical Application
• Enhancing Self-Consumption: At daytime, the electricity from the PV array is used for self-consumption. The surplus is used to charge the batteries, which in turn can power the loads at night. The utilization of energy storage technologies can bring the self-consumption rate up to 95%.
• Provide Backup to Critical Loads: When the grid fails, the backup function of the hybrid inverter can feed power to critical loads such as refrigerators, routers, lamps, computers and other key appliances. The system automatically switches to backup mode within 10 milliseconds.
System Wiring and Operation
The GoodWe AC-coupled retrofit inverters are formed by the following key elements into one single unified unit: power inverter, the battery charging & discharging function, the BMS communication and the by-pass & backup function. This kind of inverter is designed to make it easy to convert and upgrade existing grid-tied systems into hybrid ones. It is suitable for both single-phase and three-phase systems, and it is also compatible with various power sources including solar and wind generators of different brands in both residential and commercial scenarios.
In a similar way to the hybrid system, the default setting in the AC coupled retrofit inverter prioritizes the PV generation to power the loads, then charge the battery and finally export any surplus power to the grid. There are also three basic operation modes available in the PV Master App. One major difference to a newly installed hybrid system is that PV will not work during the day time if there is an outage. This is because the original grid-tied inverter does not work when the grid fails and it is only the battery that powers the critical loads during the time that the outage lasts.
GoodWe Retrofit Family
3. Extended Operation Scenarios
Based on their key functions and capabilities, the GoodWe energy storage inverters can be displayed on multiple scenarios. Below are some of the most frequent.
3.1 Paralleling Scenario (Only ET Series)
The new three-phase ET inverters paralleling solution is particularly designed to meet the increasing demand for PV storage systems with higher capacity, which is completely suitable for installation such as small commercial storage systems. This kind of solution involves the integration on the AC side of multiple hybrid inverters (maximum 10 units) into one unified system.
System Wiring and Operation
The use of the SEC1000 (GoodWe’s Smart Energy Controller) is recommended to achieve a smooth interconnection of all the units when working under a paralleling scenario.
It follows the same principal of the inverter paralleling scenario: when the grid is available, the PV system, the batteries and the loads share the energy in a united system. In contrast, when outage occurs, the paralleled system breaks into independent units in which the PV and the batteries supply backup power only to the corresponding loads.
3.2 Split-phase System Solution
A split-phase system, which differentiates from most European standards systems, has completely different application scenario. For such a grid, GoodWe provides a solution of a smart meter with two CTs to integrate both 110V and 220V loads on the grid side (see below).
GoodWe energy storage ES, EM, and EH series are applicable.
3.3 Solution for Generator Connection
To develop this solution, GoodWe adopts the "Generator + Solar” concept. It is a response to situations in which the power generated by the solar system may be insufficient to provide backup support to the loads, for which case a generator is connected in parallel with the backup side through an ATS (Auto Transfer Switch) to provide emergency support to the backup loads.
GoodWe energy storage ES, EM, EH and ET series are applicable.
The system is designed in a way that the solar system and the batteries prioritize the supply of energy to the backup loads. The system can also be manually adjusted to switch to the generator in order to supply the backup loads. When the solar system recovers its supply ability, the ATS resets the system so that the loads are supplied again by the solar system.
3.4 Solution to achieve solar capacity extension
The extension of solar capacity is a characteristic that makes solar energy storage systems very attractive because they help reduce the required investment , also allowing adaptation to higher power consumption patterns in both single and three phase systems. This kind of solution is suitable for the GoodWe ES, EM, EH and ET Series. It can also work with any brand of solar inverters.
System Wiring and Operation
This solution integrates both hybrid and retrofit functions into a single system. In both on-grid systems as well as hybrids, the solar energy is used to supply electricity to both back-up loads and to charge the battery before the power is injected into the grid. By adopting such a solution, the system provides a more reliable source of supply for the loads, while ensuring a sufficient supply of green energy to charge the battery.