A novel control algorithm of a three-phase PWM inverter with output LC filter

In this paper we introduce a novel control method of a three-phase PWM inverter with output LC filter. The transfer function of LC filter is the same as that of second order LPF(low pass filter) except that it has zero damping ratio. A simple method to implement second order LPF with damping ratio is adding resistor in series with reactor. But the series resistor cannot be used in real high power system because it consumes lots of energy being proportion to square of conducted current. So, proposed control strategy utilizes the measured capacitor voltages and voltage references of inverter to damp LC filter resonance instead of a series resistor. The overall transfer function is the same as second order LPF and damping ratio is also controllable via control variables. Experimental waveforms are presented to verify LC filter control algorithm.

[1]  Y. Kawabata,et al.  Novel vector control system using deadbeat controlled PWM inverter with output LC filter , 2002, Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344).

[2]  I. Kioskeridis,et al.  Thermal and slip effects on rotor time constant in vector controlled induction motor drives , 2006, IEEE Transactions on Power Electronics.

[3]  J. Erdman,et al.  Effect of PWM inverters on AC motor bearing currents and shaft voltages , 1996 .

[4]  Seung-Ki Sul,et al.  Inverter output voltage synthesis using novel dead time compensation , 1996 .

[5]  P.J. Tavner,et al.  Coordinated control of an HVDC link and doubly fed induction generators in a large offshore wind farm , 2006, IEEE Transactions on Power Delivery.

[6]  Seung-Ki Sul,et al.  Induction machine parameter identification using PWM inverter at standstill , 1997 .

[7]  Y. Kawabata,et al.  Novel vector control system using deadbeat controlled PWM inverter with output LC filter. Part-2. Controller using strictly z-transformed equations , 2004, The 4th International Power Electronics and Motion Control Conference, 2004. IPEMC 2004..

[8]  J. K. Steinke,et al.  Use of an LC filter to achieve a motor-friendly performance of the PWM voltage source inverter , 1997 .

[9]  Osman Kukrer,et al.  Deadbeat control of a three-phase inverter with an output LC filter , 1996 .

[10]  M. Liserre,et al.  Design and control of an LCL-filter based three-phase active rectifier , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[11]  A. von Jouanne,et al.  Filtering techniques to minimize the effect of long motor leads on PWM inverter fed AC motor drive systems , 1995, IAS '95. Conference Record of the 1995 IEEE Industry Applications Conference Thirtieth IAS Annual Meeting.

[12]  H. Akagi,et al.  Modeling and damping of high-frequency leakage currents in PWM inverter-fed AC motor drive systems , 1995, IAS '95. Conference Record of the 1995 IEEE Industry Applications Conference Thirtieth IAS Annual Meeting.

[13]  Seung-Ki Sul,et al.  A new compensation strategy reducing voltage/current distortion in PWM VSI systems operating with low output voltages , 1995 .

[14]  Frede Blaabjerg,et al.  Step-by-step design procedure for a grid-connected three-phase PWM voltage source converter , 2004 .

[15]  J. Erdman,et al.  Effect of PWM inverters on AC motor bearing currents and shaft voltages , 1995, Proceedings of 1995 IEEE Applied Power Electronics Conference and Exposition - APEC'95.

[16]  Kwanghee Nam,et al.  A dynamic decoupling control scheme for high-speed operation of induction motors , 1999, IEEE Trans. Ind. Electron..