With the accelerating process of renewable energy development, solar energy has become the focus of the world with its large reserves, wide distribution, and other characteristics. The utilization of solar energy is in the form of photovoltaic power generation.
As global energy demands continue to rise and environmental concerns become increasingly urgent, the transition toward clean and sustainable energy sources has never been more critical. Solar energy stands out among renewable options due to its abundance and accessibility across different geographical regions. The utilization of solar energy is in the form of photovoltaic power generation. One of the most common forms of photovoltaic power generation is the microinverter, which has revolutionized the way solar energy systems operate and has become an essential component in modern residential and commercial solar installations.
What is a microinverter?
A microinverter is an electronic device used in a solar power system. It is less than or equal to 1,000 watts and has a module-level MPPT. Photovoltaic inverters are primarily used to convert the DC power generated by photovoltaic panels into AC power in order to supply power to a home or commercial grid. Unlike traditional string inverters that manage multiple panels simultaneously, microinverters are typically installed directly on the back of each solar panel, creating a more flexible and efficient distributed power generation system. This decentralized architecture offers numerous advantages in terms of system monitoring, maintenance, and overall energy production optimization.
DIFFERENT SIDE VIEW OF HIITIO MICROINVERTER
What are the components of a microinverter?
The structural design of a micro-inverter usually consists of the following major components:
1. Input circuit
It is used to receive DC power input and rectify it to convert it to DC voltage. The input circuit serves as the gateway for electrical energy entering the microinverter system. This component must be designed to handle varying voltage levels that result from changing sunlight conditions throughout the day. The input circuit typically includes capacitors and inductors that help stabilize the incoming power and prepare it for the subsequent conversion stages. Advanced input circuits also incorporate protection mechanisms to safeguard against voltage spikes or irregularities that might occur due to weather conditions or grid fluctuations.
2. Control circuit
Used to control the switching state and frequency of the switching elements to realize the conversion from DC to AC. The control circuit represents the “brain” of the microinverter, utilizing sophisticated algorithms and microprocessors to manage the entire conversion process. This circuit constantly monitors various parameters, including input voltage, output current, frequency, and temperature, to ensure optimal operation. Modern control circuits employ digital signal processors (DSPs) or microcontrollers that can execute complex control strategies, implement MPPT algorithms, and provide real-time communication capabilities for system monitoring and diagnostics.
3. Switching components
MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), IGBTs (Insulated Gate Bipolar Transistors), and other high-frequency switching components are usually used to realize high-frequency switching operations. These semiconductor devices are fundamental to the inverter’s operation, as they rapidly switch on and off thousands of times per second to create the alternating current waveform.
The selection of appropriate switching components is critical for determining the microinverter’s efficiency, power handling capability, and thermal performance. Advanced microinverters often use silicon carbide (SiC) or gallium nitride (GaN) switching devices, which offer superior performance characteristics compared to traditional silicon-based components.
4. Output Filter Circuit
Used for filtering high-frequency alternating current, removing high-frequency components, and obtaining stable alternating current output. The output filter circuit is essential for producing clean, grid-compatible AC power. It consists of carefully designed combinations of capacitors, inductors, and sometimes resistors that work together to eliminate unwanted harmonics and high-frequency noise from the output waveform.
A well-designed output filter ensures that the microinverter produces a pure sinusoidal AC waveform that meets strict grid interconnection standards and does not cause interference with other electrical equipment. The filter must balance effectiveness in harmonic reduction with minimal power loss to maintain high overall system efficiency.
5. Protection circuit
It is used to monitor and protect the working status of the micro-inverter, such as over-current, over-voltage, and over-temperature. Protection circuits are critical safety features that continuously monitor the microinverter’s operating conditions and respond to abnormal situations. These circuits implement multiple layers of protection, including short-circuit protection, ground fault detection, arc fault detection, and islanding prevention. Temperature sensors monitor the heat generated by power components, triggering cooling measures or shutdown procedures if necessary. Modern protection circuits also include diagnostic capabilities that can identify and report various fault conditions to system operators, facilitating rapid troubleshooting and maintenance.
These components cooperate to realize the function of the micro inverter. Through rational circuit design and control strategy, the micro inverter can efficiently convert DC power to AC power, which is widely used in various scenarios requiring AC power. The integration of these components requires careful engineering to achieve high efficiency, reliability, and longevity while maintaining compact physical dimensions suitable for installation on individual solar panels.
How does a microinverter work?
The working principle of a PV inverter can be briefly summarized in the following steps, which together create a seamless flow of energy from sunlight to usable electrical power:
1. Photovoltaic Module Power Generation
When the sunlight irradiates the photovoltaic module, the photons interact with the electrons in the photovoltaic material, resulting in the escape of electrons from the material and the formation of a photogenerated current. This photogenerated current is DC. The photovoltaic effect, first discovered in the 19th century, forms the foundation of solar power generation.
The efficiency of this process depends on multiple factors including the quality of the photovoltaic material, the intensity and angle of sunlight, panel temperature, and the presence of any shading or soiling on the panel surface.
2. DC Input
The photogenerated current is collected and delivered to the DC input of the PV inverter through the wires of the photovoltaic module. During this process, the DC current passes through fuses and DC disconnect switches to ensure safe and stable operation of the system. The DC wiring must be properly sized and installed to minimize power losses and ensure electrical safety.
Cable management and connection integrity are critical factors that affect system performance and longevity. Properly installed DC connections also facilitate maintenance operations and system troubleshooting when needed.
3. DC to AC Conversion
The core part of the PV inverter is the inverter circuit, which converts DC to high-frequency alternating current (AC) through the conduction and shutdown of power electronic switches (e.g., IGBT, MOSFET, etc.). This high-frequency alternating current is processed by the filter circuit and turned into a stable sinusoidal alternating current. The conversion process involves sophisticated pulse-width modulation (PWM) techniques that precisely control the switching timing to generate the desired AC waveform. The efficiency of this conversion process typically exceeds 95% in modern microinverters, representing minimal energy loss during the transformation from DC to AC power.
4. AC Output.
The converted AC power is connected to the power grid through the output of the inverter. In this process, the inverter has many internal protection functions, such as over-voltage, over-current, under-voltage, etc., to ensure the quality and stability of the output AC power. The AC output must be carefully synchronized with the grid frequency and phase to enable seamless power injection. Microinverters continuously adjust their output to match grid conditions and comply with local utility interconnection requirements, ensuring safe and efficient power delivery to the electrical system.
5、Grid-Connected or Off-Grid Operation
According to the configuration of the system and the application scenario, the PV inverter can run in grid-connected mode or off-grid mode. In the grid-connected mode, the inverter will directly connect the converted AC power to the grid to supply power to households, enterprises or large-scale power systems; in the off-grid mode, the inverter will store the converted AC power in the battery for use in grid-free environments.
Choose HIITIO Microinverters for Your Solar Power System
When it comes to selecting a reliable and high-performance microinverter solution, HIITIO stands out as a leading provider in the solar energy industry. HIITIO microinverters are engineered with cutting-edge technology and incorporate all the essential components and features discussed above, delivering exceptional efficiency, reliability, and longevity for residential and commercial solar installations. Contact HIITIO today to learn more about how our microinverter products can help you harness the power of the sun and achieve your renewable energy goals.
