In the background of the era of double control of energy consumption, the “power limitation wave” is sweeping the world. In order to further improve the stability of household electricity and avoid the trouble caused by power limitation, home inverters play an important role. It can convert DC power from energy storage batteries into AC power, so that household appliances such as TVs, refrigerators and lighting equipment can operate normally. Generally inverter output methods can be classified into several types: square wave, modified square wave and sine wave, among which pure sine wave inverter is a silent and efficient system with low loss and clean load waveform. In this article we will show you Renesas pure sine wave home inverter solution.
The solution is able to provide 230V AC at 50Hz/60Hz with a capacity (rating) range from 800VA to 1,800VA depending on the battery size and backup requirements with an intelligent battery management system (BMS) that can manage and control the product performance. In addition, the solution can display inverter battery performance statistics through an LCD display to help customers plan their activities in advance.
System Block Diagram
In this scheme, the RL78/G14 MCU is used as the core control to convert the DC battery voltage to a high frequency DC voltage via a boost circuit. This voltage is fed to a full-bridge power IGBT RBN40H65T1 and filter to convert it to a low-frequency AC sine wave output for appliances. In addition, product performance is controlled by the intelligent battery management system (BMS) RAA489206.
The RL78/G14 MCU is a low-power, high-performance general-purpose microcontroller with a minimum CPU power consumption of 66μA/MHz and a standby current of 240nA. In terms of computing performance, this MCU can achieve 51.2DMIPS of digital processing performance at 32MHz. It also includes up to 512KB Flash memory and 48KB RAM, and can provide functions such as timer with complementary PWM output and 10-bit A/D converter.
The RBN40H65T1 IGBT features trench gate and thin die technology for fast switching performance and low saturation voltage characteristics, and the low switching noise characteristics of the device eliminate the need for external gate resistors, reducing the number of components and enhancing the compactness of the design.
The RAA489206 is a 16-cell battery front-end (BFE) IC that is a fundamental component of a battery management system (BMS) that periodically scans the battery status and operating environment to optimize battery life and prevent catastrophic failures. A differential multiplexer and 16-bit ADC allow precise monitoring of battery voltage, temperature and load current to manage the overall status of the battery pack. In addition, the RAA489206 supports I2C and SPI protocols, allowing customers to connect microcontrollers in proprietary battery management solutions.
In addition to the devices introduced above, a wide range of Renesas products are integrated in this solution. Thanks to Renesas’ wide range of products, this system offers the following advantages.
Low-frequency and high-frequency inverters derived from the same solution.
Isolated systems that track the AC output.
Isolated systems with auxiliary flyback power supplies.
The RL78/G14 low-cost MCU performs low-frequency and high-frequency half-bridge driving.
