基于预测算法的自由活塞内燃直线发电机高效控制策略

Efficient Control Strategy Based on Predictive Algorithm for Free Piston Linear Generator

自由活塞内燃直线发电机具有燃料适应范围广、机械摩擦损耗小、压缩比可调等多种优势。但由于活塞运动轨迹受多重因素影响,运行工况极其复杂,系统输出功率和发电效率难以有效提升。该文以自由活塞内燃直线发电机为研究对象,提出一种基于预测算法的高效控制策略。通过预测算法计算系统预期的瞬时功率,利用空间矢量脉宽调制施加准确的电压矢量,进而减少系统的功率损耗,提高发电效率。相较于传统的直接功率控制,该策略针对自由活塞内燃直线发电机高频时变的发电特性,一方面克服了因脉宽调制开关信号延迟问题导致的效率损失,另一方面减少了因开关频率不固定而产生的噪声和损耗。搭建了基于Matlab/Simulink的控制系统模型,并在自由活塞内燃直线发电机的工况下对两种算法进行仿真对比,结果显示,该策略提升了系统的输出功率和效率,验证了控制策略的先进性。

The free piston linear generator(FPLG)has many advantages,such as wide fuel range,less mechanical friction loss and adjustable compression ratio.However,due to the influence of multiple factors on the piston trajectory,the operating conditions are extremely complex,so the output power and generation efficiency are difficult to improve.In this paper,an efficient control strategy based on predictive algorithm is proposed for FPLG:Through the prediction algorithm,the expected instantaneous power is calculated,and the accurate voltage vector is applied by SVPWM,so as to reduce the power loss and improve the generation efficiency.Compared with the traditional direct power control,this strategy aims at the high frequency and time-varying generation characteristics of the FPLG.On the one hand,it overcomes the efficiency loss caused by the PWM switch signal delay,on the other hand,it reduces the noise and loss caused by the switch frequency which is not fixed.The control system model based on Matlab/Simulink is built,and the two algorithms are simulated and compared under the real condition of the FPLG.The results show that the proposed strategy improves the output power and efficiency of the system,and verifies the correctness of the proposed strategy.