When the micro-inverter * estimates the value of specific applications, several aspects should be considered topology.
In small applications, the panel may face essentially the same light, temperature and shading and other conditions. Therefore, the micro-inverter limited role in improving efficiency.
In order to operate at different voltages of the panel to obtain the highest efficiency, require the use of DC / DC converter output voltage of the panels allows uniform operating voltage of the storage battery. In order to minimize manufacturing cost, the DC / DC converter and the inverter designed as a module. For local power line connected to the power distribution grid or the DC / AC converter can also be integrated into the module.
Solar panels have to communicate with each other, which would increase the wires and complexity. This is contained in the module into the inverter, DC / DC power converter
and the other solar panel issue.
The MCU each inverter must still have enough power to run multiple MPPT algorithm to adapt to different operating environments.
With multiple MCU will increase the overall system cost of materials.
Whenever consider changing the architecture will focus on its costs. To meet the system's price target for each panel is equipped with a controller means that the controller's costs must be competitive, smaller form factor, but it can also handle all control, communications and computing tasks.
Integrated on-chip peripherals and appropriate controls is to ensure a high degree of analog integrated system of low-cost two basic elements. For optimized to perform conversions, system monitoring and energy storage efficiency in all sectors of the developed algorithms, high performance is also required.
In addition to using the PV inverter
itself to meet the requirements, they can also handle include AC / DC converters, DC / DC converter and the panel between the communication requirements of the entire system most of the MCU, can reduce the use of multiple MCU costs resulting from increases.
These high-level requirements carefully weigh the MCU needs to determine which features are the best way. For example, when the parallel need to load balance control panel. The selected MCU must be able to detect the load current, and through the on / off output MOSFET increase or decrease the output voltage. This requires a high-speed on-chip ADC to sample the voltage and current.
Micro-inverter design is no "hard and fast" model. This means that the designer must have the ability and innovative use of new techniques, new technologies, especially between the panel and the communications between systems. The most appropriate MCU should support a variety of protocols, including some that are not typically thought of as power line communications (PLC) and Controller Area Network (CAN) and so on. Particularly in the power line communication, because no longer need a dedicated communication line, so you can reduce system costs. But this requires high performance MCU Built-in PWM, high-speed ADC and high-performance CPU.
For applications for solar inverters designed MCU, an unexpected but valuable feature is the dual-chip oscillator clock failure detection that can be used to improve reliability. Can simultaneously run two system clock capability also helps to reduce solar panel installation problems.
Since the solar micro-inverter design embodies so many innovations, the MCU, its most important feature is perhaps the software programming capability. This feature makes the design and control of the power supply circuit has the highest flexibility.
C2000 microcontrollers equipped with a highly efficient advanced digital processing algorithms computing computing processing cores as well as for energy conversion control on-chip peripherals set, has been widely used in traditional solar panel inverter topology. The new Piccolo series C2000 series microcontrollers are economic models, the series smallest package only 38 pins, but its structure is more advanced, peripherals has also been enhanced, allowing real-time control of the 32 bring the benefits of low demand overall system cost micro-inverter applications.
In addition, Piccolo MCU series of sections of the two products are integrated on-chip for clock comparison 10MHz oscillator, and bring the power-on reset and power-down protection of on-chip VREG, multiple high-resolution of 150ps PWM, a 12 4.6 mega-samples / sec ADC and I2C (PMBus), CAN, SPI and UART communication protocol interface. Figure 3 shows a micro-inverter based photovoltaic systems for use with a computer system configuration..
- 2013/08/20(火) 10:27:04|
- power converter