KR-102961560-B1 - ELECTRONIC CONTROL DEVICE USING SHUNT RESISTOR AND CURRENT DETECTION CIRCUIT

Abstract

According to the embodiments, the control unit can control the inverter more accurately by calculating the steering assist current value from the steering assist voltage value based on the input-output relationship of the operational amplifier and the resistance values of the shunt resistor and parasitic resistor.

Inventors

• 박제상

Assignees

• 에이치엘만도 주식회사

Dates

Publication Date

20260507

Application Date

20230419

Claims (7)

1. An inverter that converts electrical energy from a battery to provide a steering assist current (I) to a steering motor; A shunt resistor (Rs) connected between the inverter and ground to form a steering assist voltage (V) corresponding to the steering assist current (I); A current detection circuit comprising an operational amplifier that amplifies and outputs the steering assist voltage (V) and a parasitic resistance (Rg) occurring between the shunt resistor (Rs) and the ground; and A control unit that converts the steering assist voltage value (Vout) amplified in the above current detection circuit into a steering assist current value (Imotor) and controls the inverter with a driving signal output according to the converted steering assist current value (Imotor); Includes, The above control unit is, The method is characterized by calculating the steering assist current value (Imotor) from the steering assist voltage value (Vout) based on the input-output relationship of the operational amplifier and the resistance values of the shunt resistor (Rs) and the parasitic resistor (Rg). The above current detection circuit is, It includes a first resistor (R2) connected between one end of the shunt resistor (Rs) and the positive input terminal (Vop+) of the operational amplifier; and a second resistor (R0) connected between the positive input terminal (Vop+) of the operational amplifier and the power supply voltage (Vcc). It includes a first voltage divider resistor (Rd1) connected between the second resistor (R0) and the power supply voltage (Vcc); and a second voltage divider resistor (Rd2) connected between the second resistor (R0) and the ground. A third resistor (R1) connected between the other end of the shunt resistor (Rs) and the negative input terminal (Vop-) of the operational amplifier; and a fourth resistor (Rf) connected between the negative input terminal (Vop-) and the output terminal (Vout) of the operational amplifier; are included. An electronic control device using a shunt resistor and a current detection circuit, comprising: a buffer connected between the second resistor (R0), the first voltage divider resistor (Rd1), and the second voltage divider resistor (Rd2).
2. In Article 1, The above control unit is, An electronic control device using a shunt resistor and a current detection circuit, characterized by selecting one of the resistance values of a pre-stored parasitic resistor (Rg) that corresponds to the current detection circuit and calculating the steering assist current value (Imotor) from the steering assist voltage value (Vout).
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7. In Article 1, An electronic control device using a shunt resistor and a current detection circuit, characterized in that the formula for calculating the steering assist current value (Imotor) from the steering assist voltage value (Vout) is calculated through the following mathematical formula.

Description

Electronic Control Device Using Shunt Resistor and Current Detection Circuit The present embodiments relate to an electronic control device using a shunt resistor and a current detection circuit. When the driver operates the steering wheel, the electric power steering system detects the input steering torque through a torque sensor and transmits it to the control unit (ECU). The control unit (ECU) identifies the driver's steering intention determined by the steering torque and drives the steering motor to provide steering assistance, thereby enabling the driver to easily operate the steering wheel. At this time, the electric power steering system detects the steering assist current flowing to the steering motor and transmits it to the control unit (ECU), and the control unit (ECU) precisely controls the steering motor by comparing the driving current supplied to the steering motor with the steering assist current actually flowing from the steering motor. If the error value of the detected steering assist current is large, the control of the steering motor becomes imprecise, leading to problems such as unintended steering torque or vibration when the driver operates the steering wheel. FIGS. 1 and FIGS. 2 are block diagrams showing an electronic control device using a shunt resistor and a current detection circuit according to the embodiments of the present invention. FIG. 3 is a circuit diagram showing a part of a current detection circuit according to the embodiments. FIG. 4 is a circuit diagram showing a part of a current detection circuit according to the embodiments. FIG. 5 is an effective circuit diagram of the offset voltage stage of the current detection circuit according to the embodiments. FIG. 6 is a circuit diagram in which a buffer is applied to the offset voltage of a current detection circuit according to the embodiments. FIG. 7 is an effective circuit diagram of the offset voltage stage separated up to the second resistor of the current detection circuit according to the embodiments. FIG. 8 is a circuit diagram with a parasitic resistance applied to a current detection circuit according to the embodiments. FIG. 9 is a graph showing the measurement error due to parasitic resistance of the current detection circuit according to the embodiments. FIG. 10 is a circuit diagram in which a parasitic resistance is applied to the current detection circuit according to the embodiments and a buffer is applied to the offset voltage. FIG. 11 is a graph showing the measurement error due to element dispersion of the current detection circuit according to the embodiments. Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the exemplary drawings. In assigning reference numerals to the components of each drawing, the same components may have the same reference numeral as much as possible, even if they are shown in different drawings. Furthermore, in describing the embodiments, if it is determined that a detailed description of related known components or functions may obscure the essence of the technical concept, such detailed description may be omitted. Where terms such as "comprising," "having," or "consisting of" are used in this specification, other parts may be added unless "only" is used. Where a component is expressed in the singular, it may include a plural unless otherwise specified. Additionally, terms such as first, second, A, B, (a), (b), etc., may be used to describe the components of the present disclosure. These terms are used merely to distinguish the components from other components, and the nature, order, sequence, or number of the components are not limited by such terms. In describing the positional relationship of components, where it is stated that two or more components are "connected," "combined," or "joined," it should be understood that while the two or more components may be directly "connected," "combined," or "joined," they may also be "connected," "combined," or "joined" with other components "intervened." Here, the other components may be included in one or more of the two or more components that are "connected," "combined," or "joined" with one another. In describing the temporal flow relationship regarding components, methods of operation, or methods of production, for example, when the temporal or sequential relationship is described using "after," "following," "next," or "before," it may include cases where the relationship is not continuous unless "immediately" or "directly" is used. Meanwhile, where numerical values or corresponding information regarding a component (e.g., levels, etc.) are mentioned, even without separate explicit notation, the numerical values or corresponding information may be interpreted as including a range of error that may occur due to various factors (e.g., process factors, internal or external shocks, noise, etc.). FIGS. 1 and 2 are block diagrams showing an electronic control device using a shunt