Method for controlling a converter, control device for a converter and converter
AssigneeRobert Bosch GmbH
InventorsFlorian Malchow, Michele Hirsch, Tino Merkel
Life of this patent
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Abstract
The invention relates to the controlling of a rectifier with multiple electrical phases. In at least one electrical phase, the duty cycles are merged with one another in two consecutive cycles of the pulse-width modulated controlling, i.e. in a first PWM-pulse, the duty cycle is shifted to the end of the PWM-pulse, and in a subsequent PWM-pulse, the duty cycle is shifted to the start of the PWM-pulse. As a result, there must be no switching process between two consecutive PWM-pulses. In this way, the switching losses and consequently the rise in temperature of the rectifier can be minimised.
Claims8
A method for controlling a converter (1) having a plurality of electrical phases, comprising the following steps:
- determining (S1) duty ratios for switched-on durations of pulses for pulse-width-modulated control of the electrical phases of the converter (1) in a time frame, wherein the time frame is formed by units of a PWM clock cycle (I, II) of the pulse-width-modulated control;
- and
- adapting (S2) the switching-on points in time and switching-off points in time for the pulse-width-modulated control of the electrical phases, wherein for a first phase in a first PWM clock cycle (I) a switched-on duration is set completely at the end of the first PWM clock cycle (I) and, in a second PWM clock cycle (II) following the first PWM clock cycle (I), the switched-on duration of the first phase is set at the beginning of the second PWM clock cycle (II), wherein the first electrical phase of the converter (1) comprises an electrical phase having the largest duty ratio of the electrical phases of the converter (1), and wherein a conventional control switching takes place for one or more of the other electrical phases during the first PWM clock cycle and the second PWM clock cycle, and wherein the duty ratios of the electrical phases correspond to the duty ratios determined.
A control device (4) for a pulse-width-modulated converter (1) having a plurality of electrical phases, comprising:
- a control unit designed to determine duty ratios for switched-on durations of pulses of pulse-width-modulated control of the electrical phases of the converter (1) in a time frame, wherein the time frame is formed by units of a PWM clock cycle (I, II) of the pulse-width-modulated control, and the control unit is designed to set switching-on points in time and switching-off points in time for the pulse-width-modulated control of the electrical phases, wherein for a first electrical phase in a first PWM clock cycle (I) the switched-on duration is set completely at the end of the first PWM clock cycle and, in a second PWM clock cycle (II) following the first PWM clock cycle (I), the switched-on duration of the first electrical phase is set at the beginning of the second PWM clock cycle (II), wherein the first electrical phase of the converter (1) comprises an electrical phase having the largest duty ratio of the electrical phases of the converter (1), and
- wherein a conventional control switching takes place for one or more of the other electrical phases during the first PWM clock cycle and the second PWM clock cycle, and wherein the duty ratios of the electrical phases correspond to the duty ratios determined.
Dependencies are inferred from the claim text.