The static total rated power is approximately 6.83 kW. After accounting for motor startup surges and the simultaneous operation factor, the peak power demand is approximately 9–11 kW. The 15 kW inverter unit provides ample headroom, and its short-term overload capacity can easily handle the startup of inductive loads.

In terms of operating hours, the core power equipment runs continuously 24 hours a day, while auxiliary devices start and stop according to processing loads. During the day, there is a high degree of overlap between the load and photovoltaic output, resulting in an ideal self-consumption ratio; at night, as demand decreases, the energy storage system supplies power, with the grid filling any gaps.

In terms of capacity allocation, the 22.5 kW photovoltaic system corresponds to an average daily power generation of 112.5 kWh, resulting in a high direct coverage rate; the 48 kWh energy storage system, with a 90% depth of discharge, provides approximately 43.2 kWh of usable energy, which can stably support the continuous off-grid operation of the site’s core loads while delivering dual benefits of emergency backup power and daily peak shaving and valley filling.

The system employs a three-phase, three-wire hybrid grid-connected energy storage topology and consists of five major subsystems: a photovoltaic array, a hybrid inverter, a lithium iron phosphate energy storage system, an AC power distribution system, and a remote monitoring system. DC power from the photovoltaic array is fed into the MPPT input of the inverter, while the energy storage batteries are directly connected to the inverter unit via the DC bus. The AC side is synchronously connected to the utility grid and the on-site load bus.

Grid-connected mode is the normal operating mode: PV power is prioritized to supply local loads; surplus power charges the batteries; once fully charged, excess power is fed into the grid; when PV output is insufficient, the batteries supplement the supply; and if there is still a shortfall, the utility grid provides backup. Energy dispatch is automatically handled by the hybrid controller without the need for manual intervention.

In the event of a grid outage, undervoltage, overvoltage, or frequency deviation, the inverter unit disconnects from the grid and switches to standby mode within 10 milliseconds; the PV system and energy storage then jointly supply power, with no noticeable power interruption on the load side. Once the grid is restored, the system automatically reconnects, ensuring a smooth transition throughout the process.

The system includes a reserved generator port and is compatible with diesel generator sets as a third backup to address extreme prolonged rainy weather. Intelligent load management can selectively connect or disconnect non-critical loads based on battery SOC, ensuring priority power supply for core equipment.
Key Specifications: PV installed capacity 22.5 kW, inverter rated output 15 kW, energy storage capacity 48 kWh, AC rated voltage 415 V three-phase, average daily standard power generation 112.5 kWh, average daily sunshine duration 5 hours, MPPT voltage range 150 V–850 V, grid-connected/off-grid switching time ≤10 ms.

The entire site consists of 36 modules, with 12 modules connected in series to form one string, and three such strings connected in parallel. With an open-circuit voltage of 49.8 V per module, the open-circuit voltage of a string consisting of 12 modules in series is 597.6 V. This falls within the mid-to-high range of the inverter’s MPPT operating range (150 V–850 V), providing sufficient margin for voltage boost at low temperatures and voltage reduction at high temperatures, ensuring stable maximum power point tracking across all temperature ranges throughout the year.

In terms of current, the short-circuit current of a single string is approximately 15.93 A, and the total current of three strings connected in parallel is less than 48 A. The inverter’s two MPPT channels are connected via a 2-string-plus-1-string configuration, with the current in each channel remaining within the rated range and offering ample margin. This connection method features clear wiring, facilitating grouped operation and maintenance as well as fault localization.

Each battery is equipped with a built-in intelligent BMS that integrates a full suite of protections against overcharge, over-discharge, overcurrent, overtemperature, and short circuits. It features an active balancing circuit to maintain cell consistency and extend the service life of the entire battery pack. The BMS continuously monitors the voltage, temperature, and loop current of each cell in real time, proactively triggering protection measures and reporting alarms in the event of anomalies.

Communication supports RS485, CAN 2.0, and Bluetooth, with native compatibility for mainstream hybrid grid inverter protocols; the CAN bus enables data interoperability. The inverter can read parameters such as SOC, SOH, voltage, current, and temperature to achieve precise charge and discharge control. A companion mobile app connects directly via Bluetooth, allowing for convenient remote monitoring of operating status and alerts.

The total energy storage capacity of 48 kWh, calculated based on a standard 90% depth of discharge, provides approximately 43.2 kWh of usable energy. This fully covers the site’s nighttime base load and emergency power needs during short-term power outages, ensuring a stable and uninterrupted power supply for core production equipment. The emergency backup capacity is fully aligned with the project’s operational requirements.

In grid-connected mode, the energy storage system serves a dual role in peak shaving and off-peak charging: it charges during the day using surplus solar power and discharges during evening peak hours, reducing electricity costs while preventing curtailed generation. In the event of a brief grid outage, it immediately takes over the load until power is restored or the backup generator is started.

Under standard cycle life conditions, the system achieves over 8,000 cycles; based on an average of 0.5 cycles per day, its service life far exceeds fifteen years. It supports up to 16 units in parallel, expandable to 256 kWh; future capacity expansion requires only the addition of battery cabinets, with no need to replace the inverter side.

The core control unit employs a 15 kW three-phase grid-tied energy storage inverter capable of connecting up to 24 kW of PV capacity; the project’s 22.5 kW capacity leaves room for future expansion. It features a transformerless topology with a maximum efficiency of 97.6%, a European efficiency rating of 97%, and an MPPT efficiency of 99.9%. It features two independent MPPT channels, each with a maximum input current of 50 A, supporting the connection of modules with different orientations and tilt angles.

It supports 100% three-phase unbalanced loads, with each phase capable of independently carrying up to 50% of its rated load, accommodating conditions of uneven load distribution. It can handle a 200% overload for 10 seconds, effectively managing motor startup surges, preventing tripping during startup, and ensuring high system reliability.

Grid-tied/off-grid switching time is ≤10 ms, an industry-leading performance. Traditional contactor switching takes tens to hundreds of milliseconds, often causing equipment to restart after motor shutdowns; 10-millisecond-level switching is virtually transparent to the load, ensuring uninterrupted process continuity. The off-grid output is a pure sine wave with THDv below 3%, ensuring stable operation of both linear and nonlinear loads.

An integrated generator input port supports the connection of diesel generators as backup power sources; during prolonged rainy periods when battery levels are low, the system automatically starts the generator to replenish power. Intelligent load management supports a tiered load shedding strategy, sequentially disconnecting non-critical loads based on State of Charge (SOC) to prioritize power supply to core equipment.

Supports up to six units in parallel, with total capacity expandable to 90 kW. Plant capacity expansion requires only adding units and connecting them in parallel; the load is automatically distributed evenly. The unit’s IP66 rating allows for direct outdoor installation, with an operating temperature range of -30°C to +60°C; derating occurs only at temperatures above 45°C, making it suitable for Malaysia’s high temperatures. Intelligent air-cooling ensures noise levels ≤50 dB(A).

Equipped with an OLED display and physical buttons, it supports RS485 and USB. An optional Wi-Fi module enables cloud monitoring, remote data viewing, and report export.

The DC-side modules are connected in series via MC4 connectors and connected to the inverter’s DC input via 6-square photovoltaic-grade cable. The cable is UV-resistant and withstands extreme temperatures; the inverter features a built-in DC isolator and reverse-connection protection to ensure safety during maintenance power-offs.

On the battery side, 25-square-millimeter high-cross-section connecting wires are used to meet high-current carrying requirements. After four units are connected in parallel, they are connected to the inverter’s battery port. The circuit is equipped with multi-level protection comprising DC circuit breakers and fuses, which, combined with BMS overcurrent protection, forms multiple layers of safety safeguards.

The AC side is configured with a complete power distribution circuit, including a grid-connection switch, load switch, surge protection, and ground-fault circuit interrupter (GFCI). The grid side and load side are designed independently, ensuring that maintenance on one does not affect the other. The inverter features built-in AC and DC Type II/III surge protection, which, combined with external lightning protection, meets industrial site requirements.

Comprehensive safety protection functions are included, covering reverse polarity protection, insulation monitoring, residual current monitoring, short-circuit protection, ground fault protection, islanding protection, and optional AFCI arc fault protection—all built-in without the need for additional installation.

Construction consists of six phases: mounting the support structures, installing the modules, securing the inverters, positioning the energy storage systems, laying cables, and commissioning the system. The support structures must be designed based on local wind load calculations to ensure structural safety.

It is recommended that inverters be installed in a well-ventilated semi-outdoor area; although IP66-rated units are suitable for outdoor use, a shaded environment is more conducive to extending their service life. Battery cabinet racks should be stacked, with four units centrally arranged in an indoor equipment room at an ambient temperature of 15°C to 35°C, ensuring adequate ventilation.

Cable routing must separate high- and low-voltage AC and DC circuits. Outdoor connectors must be waterproofed, and the grounding system must be installed in accordance with standards. Commissioning involves powering up the system in stages—DC, AC, and battery—in that order. The system is delivered after completing grid-connection settings, communication pairing, switching tests, and load testing.

Routine operation and maintenance primarily consists of regular inspections, with a comprehensive inspection recommended every six months.

In terms of economic benefits, the system generates an average of approximately 112.5 kWh per day and about 41,000 kWh per year. Based on Malaysia’s industrial electricity rates, this translates to substantial annual savings on electricity bills. Combined with revenue from the peak-to-off-peak price differential in energy storage, the payback period is reasonable. Given the long service life of the modules and batteries, the system generates long-term net returns after the initial investment is recouped.

Power supply reliability is the core value. In industrial settings, power outages can lead to process interruptions, product scrapping, or even environmental penalties. The uninterrupted power supply provided by the grid-tied energy storage system essentially ensures production continuity. With a seamless 10-millisecond switchover and 64 kWh of backup power, the system covers the vast majority of short-term power outages and voltage fluctuations.

In summary, this 23 kW three-phase hybrid grid-connected PV-storage system is custom-designed for the load characteristics and grid environment of Malaysia’s commercial and industrial sectors, featuring optimal component selection, comprehensive parameters, and complete protection. The combination of a 15 kW hybrid inverter, 22.5 kW high-efficiency PV modules, and a 48 kWh lithium iron phosphate (LiFePO₄) energy storage system strikes a balance between power generation efficiency, power supply reliability, scalability, and cost-effectiveness, addressing both current production power needs and future system expansion and upgrade potential.