Patent us20040131114 – pulse width modulation method, pulse width modulator, power conversion … – google patentsuche

While, in the Japanese Patent Application Laid-Open No. Pulse width modulation for power converters pdf 2001-327173, the electric current pulse width of the DC side is corrected so as to have enough width to the steady detection of the electric current pulse width in the first half of one cycle of carrier wave for the pulse width modulation. Pulse width modulation definition Moreover, the AC side voltage is corrected to become the desired voltage in the latter half. Pulse width modulation circuit for hho Therefore, a pulse width necessary for detecting the electric current is not secured in the latter half. Pulse width modulation inverter pdf Moreover, it is necessary to operate the modulated wave at a cycle of one half of the carrier wave cycle.


Pwm pulse width modulation definition Therefore, a highly efficient microcomputer is necessary for the operation. Sinusoidal pulse width modulation pdf Further, an electric current pulse width necessary to detect the electric current might not be able to be secured even in the Japanese Patent Application Laid-Open No. Pulse width modulation servo 2001-327173.

The device shown in FIG. Pwm pulse width modulation 1 includes rectification circuit 2, smoothing capacitor 3, current detector 5, electric current detecting element 7, motor control part 8 which outputs a first AC voltage instruction signal based on a speed instruction given from the outside, voltage instruction correction part 9 which generates a second AC voltage instruction signal by correcting the first AC voltage instruction signal, PWM control unit 6 which modulates in pulse width based on said second AC voltage instruction signal, and outputs a gate signal, and power converter 10 which has switching elements Qu, Qv, Qw, Qx, Qy, Qz for converting into an AC voltage by switching a DC voltage based on the gate signal, for converting the DC voltage into the AC voltage, AC power supply 1, and motor 4.

Concretely, each of the differences between the first AC voltage instruction signals Eu, Ev, and Ew and the second AC voltage instruction signals Eu?, Ev?, and Ew? is multiplied, and the error integrated values dEu, dEv, and dEw are obtained in voltage instruction correction part 9. Pulse width modulation led dimmer The difference between two arbitrary AC voltages of the second AC voltage instruction signals Eu?, Ev?, and Ew? is processed to become more than the predetermined value based on the values obtained by multiplying the error integrated values dEu, dEv, and dEw by each of the first AC voltage instruction signal Eu, Ev, and Ew.

By the above-mentioned processing, the largest value among the third AC voltage instruction signals Eu 0, Ev 0, and Ew 0 is substituted for the first maximum voltage Ea. Pulse width modulation inverter design The intermediate value is substituted for the first intermediate voltage Eb. Pulse width modulation frequency Further, the smallest value is substituted for the first minimum voltage Ec. Pulse width modulation pwm Next, the correction processing is executed. What is pulse width modulation pdf The second maximum voltage Ea?, the second intermediate voltage Eb? and the second minimum voltage Ec? obtained by the correction processing is substituted for the second AC voltage instructional signals Eu?, Ev?, and Ew? according to the magnitude of the third AC voltage instruction signals Eu 0, Ev 0, and Ew 0. Pulse width modulation principle Moreover, the errors of the first AC voltage instruction signal Eu, Ev, Ew and the second AC voltage instruction signals Eu?, Ev?, Ew? by the correction are managed with error integrated values dEu, dEv, and dEw. Pulse width modulation of z source inverters The error integrated value does not keep increasing because the operation is executed including the error until last time by processing with the third AC voltage instruction signals Eu 0, Ev 0, and Ew 0 in which error integrated values dEu, dEv, and dEw are added.

PWM control unit 6 has carrier wave generation part 601, U-phase comparison part 602, V-phase comparison part 603, W-phase comparison part 604, and reversing part 605, 606, 607. Pulse width modulation using microcontroller Carrier wave generation part 601 outputs carrier wave C which is triangular wave of frequency Fc based on carrier wave frequency instruction Fc. Pulse width modulation circuit using op amp U-phase comparison part 602 where gate signal Gu is output compares U-phase AC voltage instruction signal Eu and carrier wave C. Pulse width modulation dc motor control circuit H level is output when U-phase AC voltage instruction signal Eu is larger than carrier wave C. Modified sinusoidal pulse width modulation Otherwise, L level is output. Pulse width modulation graph Moreover, reversing part 605 where gate signal Gx is output outputs H level when gate signal Gu is in L level, and outputs L level when gate signal Gu is in H level.

Therefore, when gate signals Gu, Gv, and Gw are all at L level, U-phase gate signal Gu changes from the state of L level into H level in the beginning of the period of time T 1-T 2. Practical applications of pulse width modulation Next, V-phase gate signal Gv changes into H level delaying only at the time which corresponds to the difference between the second U-phase AC voltage instruction signal Eu? and the second V-phase ac instruction Ev?. Single pulse width modulation Afterwards, W-phase gate signal Gw changes into H level delaying only at the t time which corresponds to the difference between the second V-phase AC voltage instruction signal Ev? and the second W-phase AC instruction Ew?. Pulse width modulation arduino code Therefore, because the differences between the second AC voltage instruction signals Eu?, Ev?, and Ew? are lowest voltage Emin or more, the time which at least corresponds to lowest voltage Emin will be secured by the time another gate signals is changed after the arbitrary gate signal is changed.

[0075]FIG. Pulse width modulation output 7 shows the case where U-phase motor electric current Iu and V-phase motor electric current Iv are positive and W-phase motor electric current Iw is negative. Pulse width modulation techniques ppt When gate signals Gu, Gv, and Gw are all at L level, gate signals Gx, Gy, and Gz are at H level. Pulse width modulation pdf At this time, switching elements Qu, Qv, and Qw are in an OFF state, and switching elements Qx, Qy, and Qz are in an ON state. Pulse width modulation ppt Therefore, the electric current flows from switching elements Qx and Qy to motor 4, flows from motor 4 to switching element Qz, and returns to switching element Qu and Qy again. Pulse width modulation lab manual Therefore, the electric current does not flow to the DC current side, and DC current Idc is 0.

Next, X-phase gate signal Gx changes into L level when U-phase gate signal Gu changes into H level, and switching element Qu turns to an ON state and switching element Qx turns to an OFF state. What is pulse width modulation At this time, the electric current flows from a positive pole of smoothing capacitor 3 to motor 4 through switching element Qu, and flows from motor 4 to a negative pole of smoothing capacitor 3 through switching element Qy and Qz. How does pulse width modulation work Therefore, the same electric current as U-phase motor electric current Iu flows to DC current Idc. Pulse width modulation circuit using 555 timer Therefore, when the DC current is detected during this period, U-phase motor electric current Iu can be detected.

Next, Y-phase gate signal Gy changes into L level when V-phase gate signal Gv changes into H level, and switching element Qv turns to an ON state and switching element Qy turns to an OFF state. Pulse width modulation using 555 timer ic At this time, the electric current flows from a positive pole of smoothing capacitor 3 to motor 4 through switching element Qu and Qv, and flows from motor 4 to a negative pole of smoothing capacitor 3 through switching element Qz. Pulse width modulation 555 Therefore, the same the electric current with reverse polarity as W-phase motor electric current Iw in the magnitude flows in DC current Idc. Sine triangle pulse width modulation Therefore, when DC current is detected during this period, W-phase motor electric current Iw can be detected.

Therefore, the period from the change of gate signal Gu into H level from L level to the change of gate signal Gv into H level from L level, and the period from the change of gate signal Gv into H level from L level to t he change of gate signal Gw into H level from L level are necessary to be secured enough to detect DC current Idc. Pulse width modulation theory pdf This period is decided depending on the difference between the second V-phase AC voltage instruction signal Ev? and the second W-phase AC voltage instruction signal Ew?, and the difference between the second U-phase AC voltage instruction signal Eu? and the second V-phase AC voltage instruction signal Ev?. Pulse width modulation led dimming The period when DC current Idc is detected can be secured by setting lowest voltage Emin to the value which corresponds to the time enough to detect DC current Idc when these differences are corrected to be at lowest voltage Emin or more.

Although the error integrated value is used to control the voltage error due to the correction in this embodiment, the processing concerning the error integrated value can be omitted in the case that the demand for the voltage error is not severe. Pulse width modulation nptel Concretely, processing 313 is omitted by assuming error integrated value dEu, dEv, and dEw to be 0 in processing 300 of FIG. Types of pulse width modulation techniques 3 and using the first AC voltage instruction signal Eu, Ev, and Ew as the third AC voltage instruction signal Eu 0, Ev 0, and Ew 0. Pulse width modulation using ic 555 As a result, the processing can be reduced. What is pulse width modulation pwm In this case, the difference of two arbitrary AC voltage instruction signal of the second AC voltage instruction signal Eu?, Ev?, and Ew? is set to become more than the predetermined value based on the first AC voltage instruction signal Eu, Ev, and Ew in voltage instruction correction part 9.

There is no problem in the electric current detection even when the update of the correction result is performed at the integral multiply of the half cycle of the carrier wave, because the electric current pulse width of the DC current can be secured more than the width which can detect the electric current without fail. Pulse width modulation labview Therefore, because the operation cycle can be enlarged, the amount of the operation each unit time in the pulse width modulation method can be decreased, and the interval when the pulse changes is secured, the pulse width modulation where mutual interference of the switching is not generated can be obtained.

In FIG. Theory of pulse width modulation and demodulation 8, reference numeral 201 designates a carrier wave used by the pulse width modulation in PWM control unit 6, and 801 to 804 designate timing at which voltage instruction correction part 9 updates the output. Pulse width modulation circuit pdf Voltage instruction c correction part 9 outputs the second AC voltage instruction signals Eu?, Ev?, and Ew? every one cycle of carrier wave 201. Carrier based pulse width modulation Because the pulse width of DC current Idc is secured without fail, the electric current can be detected at a half cycle of the carrier wave in this embodiment. Pulse width modulation waveform Therefore, there are not any problems in the electric current detection even if the output timing is done at a time every one cycle as shown in FIG. Pulse width modulation for power converters principles and practice download 8. Use of pulse width modulation Further, there is no problem even when the cycle of the output timing can be made to an integral multiple of half cycle of the carrier wave at within the range where the update cycle of the voltage instruction signal becomes long. Explain pulse width modulation As a result, lengthening the operation cycle in voltage instruction correction part 9 becomes possible, and the amount of the operation each unit time can be decreased, that is, the effect same as embodiment 1 is achieved.

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