Bus disturbance regulator
View Patent ↗Presented is a harmonic regulator that regulates a plurality of individual harmonics in a system having periodic torque disturbances to commanded values, including zero. For each harmonic being regulated, a feedback signal having at least one harmonic component due to the harmonic being regulated is transformed from a source reference frame to a harmonic reference frame of the harmonic being regulated to form a qd feedback signal. The qd feedback signal is subtracted from the commanded value to form a qd signal and regulated. The regulated qd signal is transformed to a destination reference frame to form a compensation signal and the compensation signal is added to a control signal to form a qd control signal that drives each harmonic being regulated towards the commanded value.
1. A method to regulate bus harmonics in a motor drive system connected to a power source, the method comprising the steps of:
for each harmonic being regulated:
transforming a bus feedback signal having at least one harmonic component due to the harmonic being regulated from a source reference frame to a harmonic reference frame of the harmonic being regulated to form a qd feedback signal, wherein the step of transforming the feedback signal includes the step of determining a harmonic angle of the harmonic being regulated, wherein the step of determining the harmonic angle comprises the steps of:
resetting an output of an integrator upon detection of a zero crossing of a sine wave having the same frequency as the frequency of the power source; and
setting the harmonic angle to the output of the integrator times the harmonic number of the harmonic being regulated;
subtracting the qd feedback signal from a commanded value to form a qd signal;
regulating the qd signal;
transforming the regulated qd signal to a destination reference frame to form a compensation signal; and
adding the compensation signal to a control signal to form a qd control signal to drive the harmonic being regulated towards the commanded value.
2. The method of claim 1 further comprising the step of filtering the qd feedback signal.
3. The method of claim 2 wherein the step of filtering the qd feedback signal comprises the step of filtering the feedback signal in the harmonic reference frame.
4. The method of claim 2 wherein the step of filtering the qd feedback signal comprises the step of filtering the qd feedback signal with a low pass filter.
5. The method of claim 1 wherein the step of adding the compensation signal to a control signal to form a qd control signal comprises the step of adding the compensation signal to a V qse synchronous frame voltage command in the motor drive system.
6. The method of claim 1 wherein the step of transforming the regulated qd signal to a destination reference frame comprises the step of transforming the regulated qd signal to the destination reference frame based upon a destination harmonic number.
7. The method of claim 1 wherein the step of transforming a bus feedback signal comprises the step of transforming a bus current feedback signal.
8. A computer-readable medium having computer executable instructions, that when executed, perform the steps of claim 1 , including that when executed, perform the step comprising determining a harmonic angle of the harmonic being regulated, wherein the step of determining the harmonic angle comprises the steps of:
resetting an output of an integrator upon detection of a zero crossing of a sine wave having the same frequency as the frequency of the power source; and
setting the harmonic angle to the output of the integrator times the harmonic number of the harmonic being regulated.
9. The computer-readable medium of claim 8 having further executable instructions, that when executed, perform the step of filtering the qd feedback signal.
10. The computer-readable medium of claim 9 wherein the step of filtering the qd feedback signal comprises the step of filtering the feedback signal in the harmonic reference frame.
11. The computer-readable medium of claim 9 wherein the step of filtering the qd feedback signal comprises the step of filtering the qd feedback signal with a low pass filter.
12. The computer-readable medium of claim 8 wherein the step of adding the compensation signal to a control signal to form a qd control signal comprises the step of adding the compensation signal to a V qse synchronous frame voltage command in the motor drive system.
13. The computer-readable medium of claim 8 wherein the step of transforming the regulated qd signal to a destination reference frame comprises the step of transforming the regulated qd signal to the destination reference frame based upon a destination harmonic number.
14. The computer-readable medium of claim 8 wherein the step of transforming a bus feedback signal comprises the step of transforming a bus current feedback signal.