The ups means uninterruptible power supply, that contains energy storage devices. It is mainly used to provide uninterruptible power supply for some equipment with higher requirements on power stability.
When the mains input is normal, the ups will supply the mains voltage regulator to the load. At this time, the ups is an AC voltage regulator, and it also charges the battery in the machine.
Inverter is the heart of ups. It converts direct current to alternating current required by the user. For ups, the quality of the inverter output voltage determines the overall performance of ups. The following is a brief introduction to the 3 control methods of the ups inverter.
1. Hysteresis Control.
Hysteresis control is a popular method used in uninterruptible power supply (ups) inverters to maintain a stable output voltage or current, especially under varying load conditions. In a ups power inverter, the primary goal is to convert DC power from a battery into a stable AC output that matches the grid specifications. Hysteresis control achieves this by rapidly switching the inverter transistors on and off to keep the output voltage or current within a predefined hysteresis band around the reference value.
The key feature of hysteresis control is its simplicity and fast dynamic response. The controller constantly monitors the output voltage or current and compares it to a set reference. If the output deviates beyond the upper or lower limit of the hysteresis band, the inverter switches are triggered to bring the output back within the acceptable range. This results in high switching frequencies during rapid changes, ensuring the output remains tightly regulated.
Hysteresis control offers several advantages, such as robust performance in the presence of load variations, non-linearities, and disturbances. It also provides excellent transient response, which is crucial for ups systems to maintain a steady output during sudden load changes or grid faults. However, the variable switching frequency associated with hysteresis control can cause electromagnetic interference (EMI) and increased switching losses, requiring careful design considerations in the inverter circuitry.
In summary, hysteresis control in ups inverters is an effective method to achieve high-performance output regulation, making it suitable for applications where fast response and robustness to disturbances are essential. Its straightforward implementation and adaptability to varying loads make it a widely used technique in modern ups systems.
2. Predictive Control.
Predictive control in ups inverters is a control strategy used to enhance the performance and efficiency of power conversion. This approach uses mathematical models to predict future behavior of the inverter's output voltage and current, allowing it to make real-time adjustments to maintain desired performance. In a ups power inverter, predictive control can significantly improve voltage regulation, reduce total harmonic distortion (THD), and enhance dynamic response during load changes or power disturbances.
Model Predictive Control (MPC) calculates optimal control actions by minimizing a cost function that considers factors like output voltage accuracy and switching losses. By predicting the future states of the inverter, MPC can proactively adjust switching states to reduce errors and improve efficiency. This method is highly effective in handling non-linearities and constraints typical in power electronics. Predictive control in ups inverters ensures continuous, high-quality power supply, making it ideal for sensitive electronic equipment that requires stable and reliable power, even during grid disturbances or outages. Overall, it offers a robust solution for improving power quality and energy efficiency in critical power applications.
3. Dead-beat Control.
Dead-beat control is a digital control technique used in ups (uninterruptible power supply) inverters to achieve fast and precise output voltage regulation. The primary goal of dead-beat control is to bring the inverter output to the desired voltage level within a finite number of sampling periods, typically one or two cycles, hence the name "dead-beat."
In a ups inverter, dead-beat control works by predicting the future behavior of the inverter's output voltage and current using a mathematical model of the system. By comparing the predicted output to the desired reference voltage, the controller calculates the necessary inverter switching actions to minimize the error in the next sample period. This approach allows for extremely fast response times, effectively compensating for load changes and maintaining a stable output voltage.
Dead-beat control is particularly advantageous in ups applications where quick response to load variations is critical, such as in sensitive electronic equipment or data centers. However, it requires accurate system modeling and precise measurement of the inverter's output parameters. Additionally, it can be sensitive to system parameter variations and disturbances, which may necessitate the use of adaptive control strategies or robust control design techniques to ensure reliable performance.
Conclusion:
Therefore, it is theoretically possible to make the output voltage very close to the reference voltage in both phase and amplitude, and to correct output voltage errors caused by load changes or non-linear loads within one switching cycle. No-beat control requires that the control pulse width must be calculated and output during the beat, otherwise it will not only destroy the control characteristics, but also affect the system stability. Inverter.com provides ups inverter with different power, ups inverter is equipped with pure sine wave output and soft-start technology.
