1. USI 1 Scaling of a controller for an active filter

2. USI 2 Procedure Design controller and identify physical controller Introduce model of various signal and variable Group gains and offsets, scaling variables Implement multiplications with shift operator

3. USI 3 A rectifier U mains I mains UDC/2 Given: U mains sinusoidal Objective: I mains sinusoidal in phase with U mains and with given amplitude Measurements: I mains and U mains

4. USI 4 Design controller and identify physical controller

5. USI 5 Sinus Rif. I mains K LC U mains I + + + - Ideal controller for rectifier with given reference current feedback term feedforward term controller reference current

6. USI 6 DSP code Physical system Sinus Rif. I mains LC U mains I + + Ref.I. + - M U 1 K LC Ideal controller with reference current proportional to mains voltage ( U M is maximal allowable voltage)

7. USI 7 Introduce model of various signal and variable conversions

8. USI 8 Sinus Rif. I RETE LC U mains I + + Ref.I. + - LEM M U I M I U M U 1 K LC Introduce gain of Hall sensor (LEM) giving end-scale voltage U LEM for end-scale current I M conversion gain from sensor inverse gain

9. USI 9 Sinus Rif. I mains LC U mains I + + Ref.I. + - LEM M U I DSP LEM U U DSP U U M LEM I U M U 1 DSP M U U M U U LEM K LC Introduce gain of analog electronics adapting output voltage range of sensor (2* U LEM ) to input voltage range of AD converter (2* U DSP ), same for voltage measurement

10. USI 10 Sinus Rif. I mains LC U mains I msina + + Ref.I. + - LEM M U I DSP LEM U U DSP U U M LEM I U + + U DSP M U 1 M U U M U U LEM Interface board K LC Introduce offset of analog electronics adapting output voltage level of sensor (- U LEM  U LEM ) to input voltage level of AD converter (0  2* U DSP ), same for voltage measurement + - U DSP + - U + + U

11. USI 11 Sinus Rif. I mains LC U mains I msina + + Ref.I. +-+ + + + + - + - LEM M U I DSP LEM U U DSP U U M LEM I U DSP IN U BIT  2 IN DSP BIT U  2 U DSP U U U M U 1 M U U M U U IN DSP BIT U  2 DSP IN U BIT  2 AD LEM Interface board AD K LC Introduce AD conversion from DSP input voltages (0  2* U DSP ) to AD register values (0  BIT IN )

12. USI 12 Sinus Rif. I mains LC U mains I + + + + Ref.I. +-+ + + + + - + - LEM M U I DSP LEM U U DSP U U M LEM I U DSP IN U BIT  2 IN DSP BIT U  2 U DSP U U U + - 2 OUT BIT 2 OUT BIT DC OUT U BIT  2 OUT DC BIT U  2 M U 1 DSP M U U M U U IN DSP BIT U  2 DSP IN U BIT  2 AD LEM PWM-DSP Interface board AD K LC Add PWM gain from register range (0  BIT out ) to average output voltage range (- UDC  UDC ) and add offset of register ( BIT out /2)

13. USI 13 Group gains and offset, scaling variables

14. USI 14 Sinus Rif. I mains K LC U mains I + + + + Ref.I. +-+ + + + + - LEM M U I + - IN DSP BIT U  2 U DSP LEM U U DSP U U M LEM I U DSP IN U BIT  2 U DSP U U + - 2 OUT BIT 2 OUT BIT DC OUT U BIT  2 OUT DC BIT U  2 M U 1 DSP M U U M U U IN DSP BIT U  2 DSP IN U BIT  2 AD LEM PWM-DSP interface board AD + - IN DSP BIT U  2 + - IN DSP BIT U  2 IN BIT 2  I M IN BIT 2  U M M U Ref.I. IN BIT I M    2 2  I M  U M BIT IN  Ref.I. 2  I M  U M BIT IN  Ref.I. IN BIT 2  U M IN BIT 2  U M IMIM Ref.I. 2  U M IN BIT I M    2 BIT IN 2  U M BIT IN DC OUT U BIT  2 BIT IN OUT BIT UMUM K   Choose signed integer format, leave offset close to converters, move gains to maintain variable sizes as much as possible as size of measurement (registers range)

15. USI 15 Implement multiplications in fixed-point representation

16. USI 16 Use shift operator Operation Y=X*0.51= (X*0.51*1024)/1024  (X*522)/1024 implemented as Y= (X*522) >> 10 because 1024=2 10