隔离型离网逆变器控制策略研究
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摘要
随着智能电网的提出,由分布式电网组成的微网被国内外学者广泛研究。此处针对离网型逆变器控制策略展开了研究。首先建立了电感电流比例控制、电容电压比例积分(PI)控制的双环控制模型。为了降低负载对输出电压的影响,提出了基于负载电流前馈的输出阻抗重构控制策略,有效地抑制了负载效应。针对基于PI的双环控制逆变器输出电压精度低、带非线性负载时低次谐波含量大的问题,提出了基于准比例谐振(PR)控制器的电压外环控制方式,实现了对给定信号的闭环无静差跟踪,降低了谐波频率点输出阻抗,减小了对应频率点输出电压谐波含量。最后,设计了1.5 kW的原理样机,并验证了所有设计。
With the introduction of smart grids,microgrids composed of distributed grids have been widely studied by scholars at home and abroad.The off-grid inverter control strategy is studied.Firstly,a double-loop control model of inductor current proportional control and capacitor voltage proportional integral(PI)control is established.In order to reduce the influence of load on output voltage,an output impedance reconstruction control strategy based on load current feedforward is proposed which effectively suppresses the load effect.Aiming at the problem that the output voltage of the double-loop controlled inverter based on PI is low and the low-order harmonic content is large with nonlinear load,a voltage outer loop control method based on quasi proportional resonance(PR)controller is proposed to realize the given signal.The closed-loop has no static difference tracking which reduces the output impedance of the harmonic frequency point and reduces the harmonic content of the output voltage of the corresponding frequency point.Finally,a 1.5 kW prototype is designed and all the designs are verified.
With the introduction of smart grids,microgrids composed of distributed grids have been widely studied by scholars at home and abroad.The off-grid inverter control strategy is studied.Firstly,a double-loop control model of inductor current proportional control and capacitor voltage proportional integral(PI)control is established.In order to reduce the influence of load on output voltage,an output impedance reconstruction control strategy based on load current feedforward is proposed which effectively suppresses the load effect.Aiming at the problem that the output voltage of the double-loop controlled inverter based on PI is low and the low-order harmonic content is large with nonlinear load,a voltage outer loop control method based on quasi proportional resonance(PR)controller is proposed to realize the given signal.The closed-loop has no static difference tracking which reduces the output impedance of the harmonic frequency point and reduces the harmonic content of the output voltage of the corresponding frequency point.Finally,a 1.5 kW prototype is designed and all the designs are verified.
引文
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[2]洪峰,单任仲,王慧贞,等.一种变环宽准恒频电流滞环控制方法[J].电工技术学报,2009,24(1):115-119.
[3]洪峰,刘军,严仰光.滞环电流控制型双Buck逆变器[J].电工技术学报,2004,19(8):73-77.
[4]唐欣,罗安,涂春鸣.基于递推积分PI的混合型有源电力滤波器电流控制[J].中国电机工程学报,2003,23(10):38-41.
[5]Hong-Seok Song,Roger Keil,Peter Mutschler,et al.Advanced Control Scheme for a Single-phase PWM Rectifier in Traction Applications[A].IEEE 38th LAS Annual Meeting[C].2003:1558-1565.