Motor Control Apparatus Using Predicted Revolution Number
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Solution Overview
Problem
Existing motor control apparatuses struggle to accurately control motor output torque during sharp changes in motor revolutions, leading to excessive power draw or supply in hybrid and electric vehicles, causing overcharge or overdischarge of the DC power supply.
Innovation Solution
A control apparatus that uses a moving average calculation of motor revolutions to estimate a predicted revolution number, which is then used to set a driving-force command value, ensuring that the motor operates within the power supply's input/output limitations by adjusting the control method based on whether the revolutions are increasing or decreasing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor control apparatus uses the calculated number of revolutions from the resolver to control output torque, then the motor can be driven and controlled based on rotor position, but a large difference is generated between the calculated number of revolutions and the actual number of revolutions during sharp changes, causing excessive power draw or supply
Solution Approach 1:
The patent applies preliminary action by predicting future revolution numbers based on past revolution data before actual control execution. The prediction unit calculates predicted revolution numbers at future timing based on historical revolution information, allowing the control system to prepare appropriate driving-force command values in advance, thereby preventing excessive power draw or supply that would occur if control were based solely on delayed calculated values
Solution Approach 2:
The patent implements feedback by continuously monitoring actual revolution numbers and using this information to refine predictions. The control apparatus reads actual revolution numbers, compares them with predicted values, and adjusts future predictions based on the difference between calculated and actual revolutions, creating a closed-loop system that adapts to changing motor conditions and prevents power supply violations
2Ease of operation
If the controller calculates the number of revolutions using the electrical angle from the resolver, then the phase of the rectangular wave signal can be determined, but delays in calculation and communication cause the calculated number of revolutions to lag behind the actual number of revolutions
Solution Approach 1:
The patent applies preliminary action by performing predictions at future timing rather than reacting to current delayed measurements. By calculating predicted revolution numbers based on past data and projecting them to future control points, the system compensates for calculation and communication delays, ensuring that control decisions are based on timely and accurate revolution information
Solution Approach 2:
The patent inverts the traditional control approach by not using the currently calculated (delayed) revolution number for control, but instead using a predicted revolution number that estimates what the actual revolution number will be at the time of control execution. This inversion of the timing relationship between measurement and control eliminates the effective delay
Data Source
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AI summary
A normal revolution number calculation unit (151) calculates a normal revolution number (Nn) of a driving motor generator in every control period, based on a signal from a rotational position sensor. A moving average calculation unit (152) calculates a moving average revolution number (NAn) of the normal revolution number (Nn) given in every control period. A predicted revolution number calculation unit (153) determines whether or not the revolution number of the motor generator is in an increasing state, from the locus of the moving average revolution number (NAn). Determining that the revolution number of the motor generator is in the increasing state, the predicted revolution number calculation unit (153) calculates a predicted revolution number based on respective moving average revolution numbers in the present and preceding control periods. The calculated predicted revolution number is set to be used as a control revolution number (MRN2) and output to a motor control unit and a torque command calculation unit (156).