Motor Control System Zero-Phase Current Ripple Suppression
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Solution Overview
Problem
Existing motor control systems for hybrid and electric vehicles experience increased losses due to pulsating zero-phase current, which is not effectively suppressed by current technologies.
Innovation Solution
A motor control system that includes an inverter and an inverter control unit, which divides the output voltage pulse of at least one phase into several pulses during one pulse period to ensure that only one polarity of zero-phase voltage is output several times, thereby reducing ripples in the zero-phase current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the output voltage pulse is divided into several pulses to output zero-phase voltage of only one polarity multiple times, then ripples in zero-phase current are suppressed and losses are reduced, but the device complexity increases
Solution Approach 1:
The output voltage pulse is divided into several smaller pulses within one pulse period. By segmenting the voltage pulse timing and polarity output, the zero-phase voltage is controlled to output only one polarity multiple times, which suppresses ripples in zero-phase current and reduces energy losses without requiring additional hardware components.
Solution Approach 2:
The inverter control unit implements periodic output of zero-phase voltage with a single polarity by dividing the pulse period into multiple segments. This periodic action pattern ensures that zero-phase voltage of only one polarity is output several times within each pulse period, effectively suppressing current ripples and reducing losses while maintaining systematic control.
2Power
If three-phase windings are configured independently without neutral point connection, then motor power is improved, but zero-phase current overlaps with driving current causing increased copper loss
Solution Approach 1:
The invention extracts and separately controls the zero-phase voltage component from the three-phase voltage output. By taking out the zero-phase voltage control independently through pulse division and polarity management, the system can suppress zero-phase current ripples without affecting the independent three-phase winding configuration that provides high motor power.
Solution Approach 2:
The inverter control unit changes the voltage output parameters by dividing pulses and controlling polarity timing. This parameter change approach transforms the zero-phase voltage characteristics to output only one polarity multiple times per period, which modifies the zero-phase current behavior to reduce overlaps with driving current and thereby reduce copper losses while maintaining motor power.
Data Source
AI summary
Pulsating current (ripple) is generated in a zero-phase current to increase a loss. A motor control system includes an inverter which drives a motor which includes windings separately wound around each phase and an inverter control unit which generates an output voltage pulse corresponding to each phase to control the inverter on the basis of a torque command value and a rotor position of the motor. The inverter control unit divides the output voltage pulse of at least one phase of the output voltage pulses into several pulses during one period of the output voltage pulse such that a zero-phase voltage of only one of positive and negative polarities is output several times from the motor in the one pulse period.