Low-cost high common-mode current acquisition amplifier circuit

Abstract

The utility model discloses a low -cost high common -mode current collection amplification circuit, including motor drive circuit and differential amplifier circuit, be provided with sampling resistance R394 on the motor drive circuit, and differential amplifier U22A is included to the differential amplifier circuit, and the positive input pin and negative input pin of differential amplifier U22A are connected respectively at both ends of sampling resistance R394, still include the capacitor 413 and the resistance R3114 that are provided with in parallel, and one end of capacitor 413 and resistance R3114 is grounded, and the other end is connected on the output of differential amplifier U22A, and still be connected with resistance R399 on the output of differential amplifier U22A, and this circuit is based on the shunt resistance of low resistance value high accuracy, adopts the differential mode amplification circuit of operational amplifier and builds, gathers the current value on the motor drive circuit, is used for diagnosing motor block rotation, short circuit, open circuit etc. Working condition, to realize accurate motor control and functional safety etc. Design target.

Description

Technical Field

[0001] This utility model relates to the field of automotive parts technology, and in particular to a low-cost high common-mode current acquisition and amplification circuit. Background Technology

[0002] As the global automotive industry accelerates its transformation towards electrification and intelligence, high-performance, high-efficiency, and high-reliability on-board motor drive systems have become one of the core technologies for new energy vehicles, including a low-cost high common-mode current acquisition and amplification circuit.

[0003] Modern motor control algorithms rely heavily on real-time, accurate measurement of motor phase currents. Current information is fundamental for calculating motor torque, flux linkage, speed, and other state variables, directly impacting vehicle acceleration performance, ride comfort, energy efficiency, and dynamic response.

[0004] Meanwhile, current is a direct indicator of the motor's load status and the operating condition of power devices (such as IGBTs / MOSFETs). Accurate current monitoring is crucial for the rapid detection and protection against faults such as overcurrent, overload, and short circuits, and is directly related to the safety of the vehicle and its occupants. Utility Model Content

[0005] The purpose of this invention is as follows: In view of the above background, we have developed a low-cost, high common-mode current acquisition and amplification circuit. This circuit is based on a low-resistance, high-precision shunt resistor and uses an operational amplifier to build a differential-mode amplifier circuit to acquire the current value on the motor drive circuit. This is used to diagnose motor stall, short circuit, open circuit and other operating conditions, so as to achieve the design goals of precise motor control and functional safety.

[0006] This utility model discloses a low-cost, high common-mode current acquisition and amplification circuit, comprising a current acquisition and amplification circuit, including a motor drive circuit and a differential amplification circuit. The key features are: a sampling resistor R394 is provided on the motor drive circuit; the differential amplification circuit includes a differential amplifier U22A, with its positive and negative input pins connected to the two ends of the sampling resistor R394; a resistor R395 is connected between the negative input pin of the differential amplifier U22A and the sampling resistor R394; a capacitor C405 is also included, with one end connected between the resistor R395 and the negative input pin of the differential amplifier U22A, and the other end grounded; a resistor R400 is connected between the positive input pin of the differential amplifier U22A and the sampling resistor R394; and a capacitor C412 and a resistor are also included in parallel. R404, capacitor C412, and resistor R404 are connected between resistor R400 and differential amplifier U22A. The system also includes capacitor C411, with one end connected to the negative input pin of differential amplifier U22A and the other end connected to the positive input pin. Resistor R383 is connected between the negative input pin and the output pin of differential amplifier U22A. Capacitor C2930 is connected in parallel with resistor R383. The system also includes capacitor C406, with one end connected to differential amplifier U22A and the other end grounded. Additionally, capacitor 413 and resistor R3114 are connected in parallel, with one end grounded and the other end connected to the output pin of differential amplifier U22A. Resistor R399 is also connected to the output pin of differential amplifier U22A.

[0007] Using the above technical solution, the sampling resistor R394 converts the drive current into voltage, and the differential amplifier U22A acquires the voltage across the sampling resistor R394. At this time, the resistance values ​​of resistors R395, R383, R400, and R404 can be changed to control the amplification factor of the circuit. Capacitors C405, C411, C412, C2930, and C406 can filter the circuit. Resistors R399, R3114, and C413 can be used for diagnostic acquisition and voltage division. This circuit is based on low-resistance, high-precision shunt resistors and uses operational amplifiers to build a differential amplifier circuit to acquire the current value on the motor drive circuit for diagnosing motor stall, short circuit, open circuit, and other operating conditions, so as to achieve precise motor control and functional safety. Furthermore, the use of high-precision voltage divider resistors and operational amplifiers with high common-mode rejection ratio reduces common-mode interference, resulting in relatively stable temperature characteristics, high bandwidth, high common-mode rejection ratio, and relatively low cost. Attached Figure Description

[0008] Figure 1This is a schematic diagram of the motor drive circuit of this utility model; Figure 2 This is a schematic diagram of the differential amplifier circuit of this utility model. Detailed Implementation

[0009] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings: In the description of this utility model, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0010] This utility model discloses a low-cost, high common-mode current acquisition and amplification circuit, including a current acquisition and amplification circuit comprising a motor drive circuit and a differential amplification circuit. In this embodiment, the motor drive circuit is equipped with a sampling resistor R394. The differential amplification circuit includes a differential amplifier U22A, whose positive and negative input pins are respectively connected to the two ends of the sampling resistor R394. A resistor R395 is connected between the negative input pin of the differential amplifier U22A and the sampling resistor R394. The circuit also includes a capacitor C405, one end of which is connected between the resistor R395 and the negative input pin of the differential amplifier U22A, and the other end is grounded. A resistor R400 is connected between the positive input pin of the differential amplifier U22A and the sampling resistor R394. The circuit also includes a capacitor C412 connected in parallel. Resistor R404 and capacitor C412 are connected between resistor R400 and differential amplifier U22A. The system also includes capacitor C411, with one end connected to the negative input pin of differential amplifier U22A and the other end connected to the positive input pin. Resistor R383 is connected between the negative input pin and the output pin of differential amplifier U22A. Capacitor C2930 is connected in parallel with resistor R383. The system also includes capacitor C406, with one end connected to differential amplifier U22A and the other end grounded. Additionally, capacitor 413 and resistor R3114 are connected in parallel, with one end grounded and the other end connected to the output pin of differential amplifier U22A. Resistor R399 is also connected to the output pin of differential amplifier U22A.

[0011] Using the above technical solution, the sampling resistor R394 converts the drive current into voltage, and the differential amplifier U22A acquires the voltage across the sampling resistor R394. At this time, the resistance values ​​of resistors R395, R383, R400, and R404 can be changed to control the amplification factor of the circuit. Capacitors C405, C411, C412, C2930, and C406 can filter the circuit. Resistors R399, R3114, and C413 can be used for diagnostic acquisition and voltage division. This circuit is based on low-resistance, high-precision shunt resistors and uses operational amplifiers to build a differential amplifier circuit to acquire the current value on the motor drive circuit for diagnosing motor stall, short circuit, open circuit, and other operating conditions, so as to achieve precise motor control and functional safety. Furthermore, the use of high-precision voltage divider resistors and operational amplifiers with high common-mode rejection ratio reduces common-mode interference, resulting in relatively stable temperature characteristics, high bandwidth, high common-mode rejection ratio, and relatively low cost.

Claims

1. A low-cost, high common-mode current acquisition and amplification circuit, comprising a current acquisition and amplification circuit, the current acquisition and amplification circuit including a motor drive circuit and a differential amplification circuit, characterized in that: The motor drive circuit includes a sampling resistor R394. The differential amplifier circuit includes a differential amplifier U22A, whose positive and negative input pins are connected to the two ends of the sampling resistor R394. A resistor R395 is connected between the negative input pin of the differential amplifier U22A and the sampling resistor R394. The circuit also includes a capacitor C405, one end of which is connected between the resistor R395 and the negative input pin of the differential amplifier U22A, and the other end is grounded. A resistor R400 is connected between the positive input pin of the differential amplifier U22A and the sampling resistor R394. It also includes a capacitor C412 and a resistor R404 connected in parallel, which are connected between resistor R400 and differential amplifier U22A. It also includes a capacitor C411, one end of which is connected to the negative input pin of differential amplifier U22A and the other end is connected to the positive input pin of differential amplifier U22A. It also includes a capacitor 413 and a resistor R3114 connected in parallel, one end of which is grounded and the other end is connected to the output terminal of differential amplifier U22A. A resistor R399 is also connected to the output terminal of differential amplifier U22A.

2. The low-cost high common-mode current acquisition and amplification circuit according to claim 1, characterized in that: A resistor R383 is connected between the negative input terminal and the output terminal of the differential amplifier U22A. A capacitor C2930 is connected in parallel with the resistor R383. The amplifier also includes a capacitor C406, one end of which is connected to the differential amplifier U22A and the other end is grounded.

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