Industry Projects

Rem.: After finishing the projects sometimes publications [ ] were done. Because the customers participated in it, these publications covered a wide area from theory up to application and market aspects.

1987 [1] Control for a static uninterruptible power supply. (Piller)

1989 [2] Master/Slave drive for the memory drum of a digital x-ray chest system with time optimal position control and active damping of transmission oscillations. (Philips Medical Systems)

1991 [3] Control of c-axis direct drive for a 30 kW CNC-tool machine. (Gildemeister)

1993 [4] Regenerative power supply for passenger lifts with stable functioning under the condition of weak grids in far east. (Schindler Lifts, Switzerland)

1995 Control of an induction motor drive for a forklift truck with stable functioning under an extremely wide range of dc-link voltage supplied by a diesel generator. (Still GmbH)

1997 [6] Control of a double-fed three-phase generator for a 2 MW wind turbine without a position sensor
(Vestas Wind Systems A/S, Denmark)

1998 DC drive control for servo steering in automobiles. (employer confidential)

1998 [6] Active compensation of generator caused current harmonics for a 2 MW wind turbine.
(Vestas Wind Systems A/S, Denmark)

1999 Active damping of transmission oscillations using the current control circuit for a 2 MW wind turbine.
(Vestas Wind Systems A/S, Denmark)

2000 [5] Control of a wire pull machine without force measurement. (Dissertation TU Brunswick and TU Munich)

2000 Speed control for an only rotor-fed asynchronous motor for service purpose.
(Vestas Wind Systems A/S, Denmark)

2000 Power control adapting itself to fast alternating grid frequencies and voltage amplitudes for 2 MW wind turbines.
(Vestas Wind Systems A/S)

2001 Control of a claw pole motor without position sensor allowing it to be used as starter and generator in an automobile. (DaimlerChrysler AG)

2002 Matlab S-Function model of the doubly-fed three-phase generator regarding saturation effects (optional). With the very little processor time needing model it is possible, to switch during simulation the stator between star/delta and grid/no grid connection. This allows e.g. the comfortable development of grid synchronisation algorithms. (Vestas Wind Systems A/S)

2002 High dynamic power control over angle and amplitude for the doubly-fed three-phase generator without fieldoriented vector operations (scalar control). The rotor current controllers operate with alternating references and do not anymore differentiate between active and reactive rotor currents. This solution in combination with an altered inverter design opened for the employer the American market, which is blocked by several patents. Meanwhile a 3 MW version of the scalar control is operating in the U.S. (Vestas Wind Systems A/S)

2003 Virtual test bench for the doubly-fed induction generator in Matlab/Simulink. The test bench comprises the already under 2002 described continuous generator model, a grid model and the stator field oriented power control for wind turbines, which is calculated within a 5 kHz discrete Matlab S-Function. The power control includes operational state machines with synchronisation, grid/no-grid connection and star/delta switching during simulation run time. The simulation is very fast and comes with actual processing units close to realtime. The control C-code is complete and with minor interface adjustments it can be integrated into the target system and its operating system. Meanwhile a 850 kW wind turbine with this control has passed the field test.
(Gamesa Eolica, Spain
)

2004 Development of a dc-link voltage control with nearly complete (approx. 95%) compensation of the harmonics caused by the doubly-fed induction generator. Compensated are the slip harmonics and overharmonics of the line frequency up to a frequency of 600 Hz. The number of harmonics, which can be reduced is only limited by the available processing power. The harmonics reduction operates completely decoupled from the power and dc-link voltage control circuits. Even under very dynamic operations with high current transients no interference can be observed between the mentioned control circuits and the harmonics reduction. To allow close to reality tests, the virtual test bench has been upgraded with a harmonics generating doubly-fed generator model on basis of field measurements. The dc-link voltage control works with cosphi=1 but can also be used as a phase shifter in other applications. (Gamesa Eolica, Spain)

2004/2005 Development of the under 2004 described power control for the doubly-fed induction generator with harmonics reduction for operation without rotor position sensor. The harmonics reduction works also under this difficult conditions effectively and reduces the slip and grid harmonics nearly completely (80% - 95%). (Gamesa Eolica, Spain)

2005 Development of an encoder model with reference signal in C. The model is compatible with the control and status register interface of the dSMC resp. VeCon digital signal processing unit (DSP). It supports the high resolution speed calculation, which evaluates the encoder counter CNTLTx and the time counter TCNTLTx  and additionally the position calculation with counter overflow evaluation and correction by reference pulse evaluation.

2005 Development of a sine cosine position sensor model with additional absolute position tracks and reference pulse in C. The model is compatible with the control and status register interface of the dSMC resp. VeCon digital signal processing unit (DSP). It calculates for each control sample the contents of the digital and analog interface registers (CNTLTx, Ax_ANA, Bx_ANA). It is possible to set the time delay between the sample time of the analog value and the latch time of the encoder counter. Additionally it is possible to add noise to the sensor tracks. The resulting quadrant errors when the position is assembled from the analog and digital components are the same as observed at the real motor test bench.

2005 Speed control for a permanently exited non-salient synchronous motor with a speed resolution of 1/32 rpm and an over 250 microseconds averaged speed accuracy of 1/4 rpm for a speed range of +/-8192 rpm. The control runs in a dSMC processing unit. The speed ist calculated in high resolution from an 8192 increments per revolution encoder. Development and test where done within the dSMC-Vision simulator using the self developed PWM, synchronous motor and encoder models. The solution was transmitted via e-mail to the employer, integrated by him into the system and successfully operated at the motor test bench. The personal presence of Control Design was not needed except for one consulting day teaching how to tune the control. (ESR Pollmeier GmbH)

2005 Speed control for a permanently exited non-salient synchronous motor using sine cosine position sensor signals with high noise. The control runs in a VeCon processing unit. Because the CNTCOR assemler command of the VeCon does not correct all quadrant errors, CNTCOR had to be replaced by a newly developed algorithm. This algorithm is a non recursive filter specially adjusted for the type of noise in the speed signal. It eliminates all quadrant errors and causes not any additional time delay in the speed calculation. Development and test where done within the dSMC-Vision simulator using the self developed PWM, synchronous motor and sine cosine position sensor models. The solution was transmitted via e-mail to the employer, integrated by him into the system and successfully operated at the motor test bench. The personal presence of Control Design at the motor test bench was not needed. (ESR Pollmeier GmbH)

2005/2006 Highly dynamic speed control for rotatory direct drives with permanently exited non-salient synchronous machines. The current control is done with 16 kHz in rotor field coordinates. The start angle for the commutation is evaluated automatically. After about 100 ms the evaluation is finished without a visible move of the rotor. In principle the evaluation process requires a minimal rotor movement. The resolution of the calculated speed can be adjusted up to 10 bit/rpm. By numerical adaptation within the speed calculation, the speed controller and the automatical evaluation of the starting commutation angle it is possible to operate the speed control for servo drives with a rotor inertia of 0,06 kgcm2 and for direct drives with round table up to an rotor inertia of 5 kgm2. Numerically it is possible to evaluate the rotor position from SinCos-Sensors starting from 1 period/rev up to 360.000 periods/rev. Additionally we have 11 bits from the arc tangent calculated from the sensors sine and cosine track. Theoretically one rotor revolution can be resolved with 737.000.000 increments. With the help of adaptations within the speed calculation there are only very small numerical losses over the specified position sensor range. The quadrant errors, which usually occur when digital and analog position components are combined to form a single position information are reliably detected and compensated. The control code was developed at the simulator in 16/32 bit fixed point arithmetic and successfully integrated at the customers test bench. The personal presence of Control Design during system integration was not needed. (ESR Pollmeier GmbH)

2006 Models of a permanently exited linear drive, linear Encoder, linear SinCos and Sixstep position sensors as basis for development of the control solution. All models are written in C.

2006 Highly dynamic position and speed control for a permanently exited linear drive. The drive control can evaluate Encoder, SinCos and Sixstep position sensors. The commutation start angle can be evaluated automatically.The control was tested with the simulator. The personal presence of Control Design during system integration was not needed. (ESR Pollmeier GmbH)

2006 Virtual Test Environment for a regenerative power supply. (Schindler Lifts, Switzerland)

2006/2007 Further improvements for the regenerative power supply for passenger lifts with stable functioning under the condition of weak grids in far east. The improvements were done on basis of the virtual test environment and integrated by the customer into the system without the need for further support by Control Design. (Schindler Lifts, Switzerland)

2007 High resolution speed control of DC-Drives for passenger lifts. The calculation of the current control parameters is done using data from motor data sheet. The development was done on basis of the virtual test bench and integrated by the customer into the system without the need for further support by Control Design.(Schindler Lifts, Switzerland)

2007 Adjustable Bandstop according to Butterworth for high resolution speed control within a servo drive application.
(ESR Pollmeier GmbH)

2007 Compensation of the pwm inverter nonlinearity for servo drive application. The compensation permits for a fixed current controller parameter set nearly constant dynamical behaviour of the current control loop over the full output voltage range.
(ESR Pollmeier GmbH)

2007 High dynamical PMSM speed control  with resolver. The speed ist filtered by a Kalman filter and permits noise free operation despite a parameter setting optimized for high dynamics. (ESR Pollmeier GmbH)

2007 Optimization of the bandwidth for current control calculated with 16 kHz.  The optimization was done within Matlab/Simulink on basis of precise models for pwm, DC-link voltage inverter, ADC and current filters. The timing for the current sampling and the pwm switching time generation was precisely modeled. This optimization has been verfied at the customers test bench without further efforts or support and was finally integrated into the system. (ESR Pollmeier GmbH)

2008 Virtual test bench for the doubly-fed induction generator (DFIG) in Matlab/Simulink. This development is an improved version of an earlier development described under the years 2003 and 2004. Further the simulation speed has been doubled.
(REnergy Electric Tianjin Ltd.,  China
)

2008/2009 Power control  C program for DFIG in an 1.5 MW wind turbine with position sensor. The control was integrated into the system without the personal presence of Control Design. (REnergy Electric Tianjin Ltd.,  China)

2008/2009 DC-Link voltage control C program for DFIG in an 1.5 MW wind turbine with position sensor. The control was integrated into the system without the personal presence of Control Design. (REnergy Electric Tianjin Ltd.,  China)

2008/2009 Harmonics reduction C program for DFIG in an 1.5 MW wind turbine with position sensor. The reduction is done for the slip and the 5th and 7th stator voltage harmonics.The development is similar to the one done in 2004. The harmonics reduction was integrated into the system without the personal presence of Control Design. (REnergy Electric Tianjin Ltd.,  China)

2010/2011 Loss optimal control (MTPC) for an IPMSM with very strong reluctance. The interior permanent magnet synchronous motor will be used within electric motor driven vehicles. The model based search algorithm allows the control of the IPMSM far into the fieldweakening range (12.000 rpm). It replaces the state of the art solution which was based on extensive measurement procedures for the characteristic field of the IPMSM. The tuning of this new algorithm is quite simple and can be compared with that of an induction motor operated in the fieldweakening range. The solution is based on a very fast numerical approach in connection with a nonlinear motor model. The Development and tests were perfomed within Matlab/Simulink. The S-Function was embedded as C-subprogram within the control environment of the employer. With TI float DSPs the algorithm allows sample rates up to 16 kHz  (Volkswagen AG)

2012/2014 Low voltage ride through (LVRT) capability according to E.ON Netz GmbH requirements for a wind turbine with DFIG . Between 45 and 55 Hz the power control operates stable even at very fast grid frequency alterations  (>> 0.1 Hz/s). During grid voltage drops down to 0 % of rated grid voltage the power control remains stable at least for the minimal required time without cutting the  generator out from the grid. Further the power control operates stable at least up to 130 % grid overvoltage. Also in case of grid  voltage imbalances up to +/- 15 % the control remains stable. During  grid voltage drops and rises down to 50 % and up to 120 % of rated grid voltage the grid voltage is  supported by the reactive power control. The grid voltage support amplification is adjustable and operates either continuously or with  adjustable deadband. To protect the dc-link circuit from damage caused by overvoltage a rotor circuit and a  dc-link circuit chopper are controlled. The LVRT was tested and approved at a specially developed high grid voltage test bench without a need for the personal presence of Control Design. Meanwhile the LVRT is part of the customer’s product portfolio. (REnergy Electric Tianjin Ltd., China)