PWM strategy for regenerative multilevel drive
First Claim
1. A method for controlling a multilevel regenerative drive having a motor, a multilevel converter, a multilevel inverter, and a controller operatively connected to the multilevel converter and the multilevel inverter, the method comprising:
- applying, by the controller, bipolar modulation to the multilevel converter of the multilevel regenerative drive during a first period;
applying, by the controller, unipolar modulation to at least one phase-leg of the multilevel converter of the multilevel regenerative drive during a second period, wherein the first period and the second period are different periods that partially overlap; and
applying, by the controller, at least one of unipolar modulation and bipolar modulation to the multilevel inverter of the multilevel regenerative drive;
wherein the applying at least one of unipolar modulation and bipolar modulation to the multilevel inverter comprises;
applying bipolar modulation to the multilevel inverter during acceleration of an elevator car from zero speed of the elevator car to about 75% of a rated speed of the elevator car, andapplying unipolar modulation to the multilevel inverter (a) during acceleration of the elevator car from the about 75% of the rated speed of the elevator car to a constant speed of the elevator car and (b) throughout movement of the elevator car at the constant speed, wherein the constant speed comprises the rated speed.
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Abstract
A method (70) for controlling a multilevel regenerative drive (30) having a converter (32) and an inverter (34) is disclosed. The method (70) may include applying at least one of unipolar modulation and bipolar modulation to the converter (32), and applying at least one of unipolar modulation and bipolar modulation to the inverter (34). A control system (52) for a mechanical system (20) having a motor (28) is also disclosed. The control system (52) may comprise a converter (32) operatively connected to a power source (29), and an inverter (34) operatively connected to the motor (28) of the mechanical system (20). At least one controller may be in communication with the converter (32) and inverter (34), and may be configured to apply at least one of unipolar modulation and bipolar modulation to each of the converter (32) and the inverter (34).
10 Citations
10 Claims
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1. A method for controlling a multilevel regenerative drive having a motor, a multilevel converter, a multilevel inverter, and a controller operatively connected to the multilevel converter and the multilevel inverter, the method comprising:
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applying, by the controller, bipolar modulation to the multilevel converter of the multilevel regenerative drive during a first period; applying, by the controller, unipolar modulation to at least one phase-leg of the multilevel converter of the multilevel regenerative drive during a second period, wherein the first period and the second period are different periods that partially overlap; and applying, by the controller, at least one of unipolar modulation and bipolar modulation to the multilevel inverter of the multilevel regenerative drive; wherein the applying at least one of unipolar modulation and bipolar modulation to the multilevel inverter comprises; applying bipolar modulation to the multilevel inverter during acceleration of an elevator car from zero speed of the elevator car to about 75% of a rated speed of the elevator car, and applying unipolar modulation to the multilevel inverter (a) during acceleration of the elevator car from the about 75% of the rated speed of the elevator car to a constant speed of the elevator car and (b) throughout movement of the elevator car at the constant speed, wherein the constant speed comprises the rated speed. - View Dependent Claims (2, 3)
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4. A control system for a multilevel regenerative drive having a motor, comprising:
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a multilevel converter operatively connected to a power source, the multilevel converter having a plurality of devices in selective communication with the power source; an multilevel inverter operatively connected to the motor of the mechanical system, the multilevel inverter and the converter connected to each other, and the multilevel inverter having a plurality of devices in selective communication with the motor; and at least one controller in communication with the multilevel converter and the multilevel inverter, the at least one controller being configured to apply bipolar modulation to the multilevel converter of the multilevel regenerative drive during a first period, apply unipolar modulation to at least one phase-leg of the multilevel converter of the multilevel regenerative drive during a second time period, and apply at least one of unipolar modulation and bipolar modulation to the multilevel inverter of the multilevel regenerative drive, wherein the first period and the second period are different periods that partially overlap; wherein the applying at least one of unipolar modulation and bipolar modulation to the multilevel inverter by the at least one controller comprises; applying bipolar modulation to the multilevel inverter during acceleration of an elevator car from zero speed of the elevator car to about 75% of a rated speed of the elevator car, and applying unipolar modulation to the multilevel inverter (a) during acceleration of the elevator car from the about 75% of the rated speed of the elevator car to a constant speed of the elevator car and (b) throughout movement of the elevator car at the constant speed, wherein the constant speed comprises the rated sped. - View Dependent Claims (5, 6, 7)
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8. An elevator system, comprising:
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an elevator car disposed in a hoistway; a motor operatively connected to the elevator car, the motor generating a thrust force to move the elevator car within the hoistway; a power source operatively connected to the motor, the power source supplying power to the motor; a multilevel converter operatively connected to the power source, the multilevel converter having a plurality of devices in selective communication with the power source; an multilevel inverter operatively connected to the motor, the multilevel inverter and the multilevel converter connected to each other, and the multilevel inverter having a plurality of devices in selective communication with the motor; and at least one controller in communication with the multilevel converter and the multilevel inverter of the multilevel regenerative drive, the at least one controller being configured to apply bipolar modulation to the multilevel converter of the multilevel regenerative drive during a first period, apply unipolar modulation to at least one phase-leg of the multilevel converter of the multilevel regenerative drive during a second time period, and apply at least one of unipolar modulation and bipolar modulation to the multilevel inverter of the multilevel regenerative drive, wherein the first period and the second period are different periods that partially overlap; wherein the applying at least one of unipolar modulation and bipolar modulation to the multilevel inverter by the at least one controller comprises; applying bipolar modulation to the multilevel inverter during acceleration of an elevator car from zero speed of the elevator car to about 75% of a rated speed of the elevator car; and applying unipolar modulation to the multilevel inverter (a) during acceleration of the elevator car from the about 75% of the rated speed of the elevator car to a constant speed of the elevator car and (b) throughout movement of the elevator car at the constant speed, wherein the constant speed comprises the rated speed. - View Dependent Claims (9, 10)
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Specification