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Electric power steering device

A technology of electric power steering and electric motor, which is applied in the direction of power steering mechanism, electric steering mechanism, automatic steering control components, etc. It can solve the problems of coil damage and current flow, and achieve simple estimation, simple temperature, and high-precision temperature estimation Effect

Inactive Publication Date: 2019-06-14
NSK LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] In such an electric power steering device, depending on the steering situation, a large current may flow through the motor (for example, when the end of the steering wheel is held in a locked state for a long time in a stationary state, etc.), when the motor inside When the coil (motor coil) reaches a high temperature such as 180°C or higher, problems such as coil damage may occur

Method used

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Embodiment Construction

[0055] In the present invention, for the estimation of the temperature (coil temperature) of the coil of each phase (U phase, V phase, W phase) in the multiphase motor, according to the heat transfer phenomenon (heat conduction, heat radiation, heat convection, etc.) between each phase ), and the heat transfer phenomenon between each coil and the substrate (control substrate) of the control unit (ECU). In a multi-phase motor, a difference in the amount of heat generated in each coil occurs due to variation in current (motor current) supplied to the coils of each phase, etc., thereby generating a temperature difference among the coils. Due to this temperature difference, a heat transfer phenomenon occurs between the phases and between each coil and the external air environment. However, a temperature difference also occurs between the control board and each coil. Usually, because the control board is close to the motor, the Heat transfer also occurs between the control substrat...

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Abstract

To provide an electric power steering device capable of estimating coil temperatures more accurately for a polyphase motor, with consideration also given to a heat-transfer phenomenon between a control board and coils in addition to heat-transfer phenomena between the coils. Disclosed is an electric power steering device comprising a control board that controls a polyphase motor including two-system motor windings, the electric power steering device comprising: a temperature sensor that detects a board temperature of the control board; and a coil temperature estimation unit that estimates, from the board temperature and all motor currents of the polyphase motor, all coil temperatures on the basis of heat-transfer phenomena between all coils caused by temperature differences between all coils and a heat-transfer phenomenon between the coils and the control board.

Description

technical field [0001] The present invention relates to an electric power steering device having a function of estimating the coil temperature of a multi-phase motor, and more particularly to an electric power steering device capable of considering heat transfer phenomena due to temperature differences between coils, And the heat transfer phenomenon between the coil and the control substrate to estimate the coil temperature. Background technique [0002] Electric power steering (EPS) that applies steering assist force (assist torque) to the steering system of the vehicle by using the rotational force of the electric motor, and applies the driving force of the electric motor to the Steering shaft or rack shaft for auxiliary control. Such a conventional electric power steering apparatus performs feedback control of a motor current in order to accurately generate assist torque. Feedback control adjusts the voltage applied to the motor so that the difference between the steeri...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02P29/64B62D5/04B62D6/00H02P25/22H02P27/08H02P29/028H02P29/68
CPCH02P25/22H02P29/032H02P29/68H02P29/64B62D5/0484B62D5/0496B62D5/0457H02P27/08B62D6/00B62D5/04
Inventor 椿贵弘三浦友博须永崇木暮伸昭上口晴彦
Owner NSK LTD