Electric Vehicle Motor Control Apparatus Voltage Stabilization
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Solution Overview
Problem
Existing control apparatuses for electric vehicles face challenges in stabilizing voltage on the power supply line during transient conditions, leading to potential damage to electronic equipment and increased costs due to the need for high-performance voltage converters and large capacitance smoothing capacitors, while also struggling to maintain balance between AC motors linked to different operational components.
Innovation Solution
A control apparatus that uses pulse waveform voltage to commutate the AC motor at predetermined electric angles, separating torque and power control detection currents to stabilize system voltage by independently controlling input electric power, thereby suppressing voltage variations and torque fluctuations without requiring high-performance converters or large capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage boosting converter with better performance and a smoothing capacitor with larger capacitance are used to stabilize voltage, then voltage stability is improved, but cost and device size increase
Solution Approach 1:
The invention changes the control parameter from conventional voltage-only control to dual control of active power and reactive power. By controlling the active power of the inverter connected to the AC motor, the system can regulate voltage stability without requiring high-performance voltage converters or large smoothing capacitors, thus resolving the contradiction between voltage stability and cost/size
Solution Approach 2:
The invention implements a feedback control mechanism where the active power of the inverter is controlled based on voltage detection results. The control apparatus detects voltage variations and adjusts the inverter's active power accordingly, creating a closed-loop system that maintains voltage stability without expensive components
2Reliability
If the inverter is controlled to make the sum of energies of two AC motors equal to 0, then voltage stability is improved, but torque control precision deteriorates due to processing delay
Solution Approach 1:
The invention segments the control functions by separating active power control (for voltage stability) from reactive power control (for torque precision). This allows independent optimization of each function, enabling voltage stabilization without compromising torque control precision even during transient conditions
Solution Approach 2:
The invention dynamically adjusts the active power of the inverter based on real-time voltage conditions while maintaining precise torque control through separate reactive power management. This dynamic separation allows the system to respond to voltage variations without introducing torque fluctuations
Data Source
AI summary
A motor control unit controls the input electric power of a MG unit to thereby suppress variations of a system voltage and stabilize the system voltage. The torque control of an AC motor and the input electric power control of the MG unit are executed independently from each other, so that the torque control and the input electric power control are stabilized. Further, torque variation zeroing control for correcting a phase of a pulse waveform voltage is executed so that a difference between a first estimated torque computed based on a torque control detection current vector of the AC motor and a second estimated torque computed based on a detection motor current vector is reduced to zero. Thus, uncomfortable torque variation is suppressed in a transient condition of the input electric power control of the MG unit.