Bus current detection and diagnosis circuit applied to full-redundancy EPS

Abstract

The utility model relates to the technical field of bus current detection, in particular to a bus current detection and diagnosis circuit applied to a fully redundant EPS (electric power storage), which comprises a first EPS subsystem, a second EPS subsystem, a vehicle body ground and a six-phase motor, and is characterized in that the first EPS subsystem comprises a first power supply, a first sampling resistor, a filter capacitor, a current limiting resistor, a first voltage stabilizing capacitor, a first differential amplifier and a first processor; and the EPS subsystem II comprises a power supply II, a sampling resistor II, a filter capacitor, a current limiting resistor, a voltage stabilizing capacitor II, a differential amplifier II and a processor II. Compared with the prior art, the sampling resistor is connected in series on the ground wire, and the voltage signal is amplified and converted by the external differential amplifier to realize current detection; and data interaction is realized through data interaction interfaces of the two processors, so that real-time and accurate detection and diagnosis of the bus current of the two sub-systems of the full-redundancy EPS are realized. The utility model has the advantages of moderate cost, higher detection precision and wider detection range.

Description

Technical Field

[0001] The utility model relates to the technical field of busbar current detection, in particular to a busbar current detection and diagnosis circuit applied to a fully redundant EPS. Background Art

[0002] Currently, the mainstream fully redundant EPS dual-subsystem design uses a common ground. This common ground design has a fatal flaw: if the ground wire harness of one EPS subsystem breaks, current can still flow back to the vehicle body ground through the ground wire of the other EPS subsystem via the common ground. The current path is not cut off, causing the ground wire harness of the other EPS subsystem to be subjected to twice the operating current for a long time, accelerating aging and posing a serious safety hazard.

[0003] To solve this problem, the usual practice is to add a bus current detection circuit to the ground wire and make a simple comparison of the detected bus currents of the two subsystems to make a fault diagnosis. The commonly used bus current detection technology solution is to add Hall sensors to the ground wires of the two subsystems. The disadvantages are high cost, large size, poor detection accuracy, and the risk of misdiagnosis of faults.

[0004] Therefore, it is necessary to design a bus current detection and diagnosis circuit for fully redundant EPS to improve detection accuracy and reduce costs. Summary of the Invention

[0005] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a busbar current detection and diagnosis circuit applied to a fully redundant EPS, so as to improve detection accuracy and reduce costs.

[0006] In order to achieve the above-mentioned purpose, the utility model is a bus current detection and diagnostic circuit applied to a fully redundant EPS, including EPS subsystem 1, EPS subsystem 2, vehicle body ground, and a six-phase motor. EPS subsystem 1 includes power supply 1, sampling resistor 1, filter capacitor 1, filter capacitor 2, filter capacitor 3, current limiting resistor 1, current limiting resistor 2, voltage stabilizing capacitor 1, differential amplifier 1, and processor 1. EPS subsystem 2 includes power supply 2, sampling resistor 2, filter capacitor 4, filter capacitor 5, filter capacitor 6, current limiting resistor 3, current limiting resistor 4, voltage stabilizing capacitor 2, differential amplifier 2, and processor 2. The positive pole of power supply 1 is connected to the power supply end of the three-phase inverter 1 of the six-phase motor, and the negative pole of power supply 1 is connected to the vehicle body ground. The No. 4 pin of the sampling resistor is connected to the vehicle body ground, the No. 2 pin of the sampling resistor is divided into three ways and respectively connected to one end of the filter capacitor one, one end of the filter capacitor two and one end of the current limiting resistor one, the other end of the current limiting resistor one is connected to the inverting input end of the differential amplifier one, the non-inverting input end of the differential amplifier one is connected to one end of the current limiting resistor two, the other end of the current limiting resistor two is divided into three ways and respectively connected to the other end of the filter capacitor one, one end of the filter capacitor three and the No. 1 pin of the sampling resistor one, the power supply end of the differential amplifier one is divided into two ways and respectively connected to the VCC power supply end one and one end of the voltage stabilizing capacitor one, the other end of the voltage stabilizing capacitor one is grounded, the ground end of the differential amplifier one, the other end of the filter capacitor two, and the filter capacitor The other end of the three is connected to the ground, the output end of the differential amplifier one is connected to the ADC end of the processor one, the digital end of the processor one is connected to the control end of the three-phase inverter one of the six-phase motor, the positive pole of the power supply two is connected to the power supply end of the three-phase inverter two of the six-phase motor, the negative pole of the power supply two is connected to the vehicle body ground, the No. 4 pin of the sampling resistor two is connected to the vehicle body ground, the No. 2 pin of the sampling resistor two is divided into three paths and respectively connected to one end of the filter capacitor four, one end of the filter capacitor five and one end of the current limiting resistor four, the other end of the current limiting resistor four is connected to the inverting input end of the differential amplifier two, the non-inverting input end of the differential amplifier two is connected to one end of the current limiting resistor three, and the other end of the current limiting resistor three is divided into three paths and respectively connected to the other end of the filter capacitor four One end, one end of the filter capacitor six and pin 1 of the sampling resistor two are connected, the power supply end of the differential amplifier two is divided into two paths and is respectively connected to the VCC power supply end two and one end of the voltage stabilizing capacitor two, the other end of the voltage stabilizing capacitor two is grounded, the ground end of the differential amplifier two, the other end of the filter capacitor five and the other end of the filter capacitor six are connected and then grounded, the output end of the differential amplifier two is connected to the ADC end of the processor two, the digital end of the processor two is connected to the control end of the three-phase inverter two of the six-phase motor, the data interaction interface of the processor two is connected to the data interaction interface of the processor one, pin 3 of the sampling resistor one, pin 3 of the sampling resistor two, the ground end of the three-phase inverter one of the six-phase motor and the ground end of the three-phase inverter two are connected and then grounded.

[0007] The processor 1 and the processor 2 are ECU chips of the electric power steering system EPS.

[0008] The models of the ECU chips include SAL-TC377TP.

[0009] The models of the differential amplifier 1 and the differential amplifier 2 include INA180-Q1.

[0010] The EPS subsystem 1 and EPS subsystem 2 are two mutually symmetrical redundant systems.

[0011] Compared to existing technologies, this new system uses a sampling resistor connected in series with the ground line and uses an external differential amplifier to amplify and convert the voltage signal to achieve current detection. Data exchange is achieved through the data exchange interface between the two processors, thereby achieving real-time and accurate detection and diagnosis of busbar current in the two subsystems of the fully redundant EPS. This new system has the advantages of moderate cost, high detection accuracy, and a wide detection range. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0013] The present invention will now be further described with reference to the accompanying drawings.

[0014] See also Figure 1 The present invention is a busbar current detection and diagnostic circuit for a fully redundant EPS system. The circuit comprises EPS subsystem 1, EPS subsystem 2, a vehicle body ground, and a six-phase motor. EPS subsystem 1 includes power supply 1, sampling resistor 1 F1A, filter capacitor 1 C1A, filter capacitor 2 C2A, filter capacitor 3 C3A, current-limiting resistor 1 R1A, current-limiting resistor 2 R2A, voltage-stabilizing capacitor 1 C4A, differential amplifier 1 3, and processor 1 5. EPS subsystem 2 includes power supply 2, sampling resistor 2 F1B, filter capacitor 4 CAB, filter capacitor 5 C2B, filter capacitor 6 C3B, current-limiting resistor 3 R1B, current-limiting resistor 4 R2B, voltage-stabilizing capacitor 2 C4B, differential amplifier 2 4, and processor 2 6. EPS subsystem 1 and EPS subsystem 2 are two symmetrical redundant systems.

[0015] The positive electrode of power supply 1 is connected to the power supply end of the three-phase inverter 1 of the six-phase motor 7, the negative electrode of power supply 1 is connected to the vehicle body ground, pin 4 of sampling resistor 1 F1A is connected to the vehicle body ground, pin 2 of sampling resistor 1 F1A is divided into three paths and respectively connected to one end of filter capacitor 1 C1A, one end of filter capacitor 2 C2A and one end of current limiting resistor 1 R1A, the other end of current limiting resistor 1 R1A is connected to the inverting input end of differential amplifier 1 3, the non-inverting input end of differential amplifier 1 3 is connected to one end of current limiting resistor 2 R2A, the other end of current limiting resistor 2 R2A is divided into three paths and respectively connected to the other end of filter capacitor 1 C1A and filter capacitor 3 C3 One end of A is connected to pin 1 of sampling resistor F1A, the power supply end of differential amplifier 3 is divided into two paths and respectively connected to VCC power supply end 1 and one end of voltage stabilizing capacitor C4A, the other end of voltage stabilizing capacitor C4A is grounded, the ground end of differential amplifier 3, the other end of filter capacitor 2 C2A, and the other end of filter capacitor 3 C3A are connected and then grounded, the output end of differential amplifier 3 is connected to the ADC end of processor 15, the digital end of processor 5 is connected to the control end of three-phase inverter 1 of six-phase motor 7, the positive pole of power supply 2 is connected to the power supply end of three-phase inverter 2 of six-phase motor 7, the negative pole of power supply 2 is connected to the vehicle body ground, sampling Pin 4 of the sampling resistor F1B is connected to the vehicle body ground, and pin 2 of the sampling resistor F1B is divided into three paths and respectively connected to one end of the filter capacitor CAB, one end of the filter capacitor C2B, and one end of the current limiting resistor R2B. The other end of the current limiting resistor R2B is connected to the inverting input end of the differential amplifier 4, and the non-inverting input end of the differential amplifier 4 is connected to one end of the current limiting resistor R1B. The other end of the current limiting resistor R1B is divided into three paths and respectively connected to the other end of the filter capacitor CAB, one end of the filter capacitor C3B, and pin 1 of the sampling resistor F1B. The power supply end of the differential amplifier 4 is divided into two paths and respectively connected to the VCC circuit. The source terminal 2 and one end of the voltage-stabilizing capacitor 2 C4B are connected, the other end of the voltage-stabilizing capacitor 2 C4B is grounded, the ground end of the differential amplifier 2 4, the other end of the filter capacitor 5 C2B, and the other end of the filter capacitor 6 C3B are connected and then grounded, the output end of the differential amplifier 2 4 is connected to the ADC end of the processor 2 6, the digital end of the processor 2 6 is connected to the control end of the three-phase inverter 2 of the six-phase motor 7, the data interaction interface of the processor 2 6 is connected to the data interaction interface of the processor 1 5, pin 3 of the sampling resistor 1 F1A, pin 3 of the sampling resistor 2 F1B, the ground end of the three-phase inverter 1 of the six-phase motor 7, and the ground end of the three-phase inverter 2 are connected and then grounded.

[0016] Processor 1 5 and processor 2 6 are ECU chips for the electric power steering system (EPS). The ECU chip model includes SAL-TC377TP, which is the preferred model. However, the ECU chip is not limited to this model; other models can also be used.

[0017] The differential amplifier 1 3 and the differential amplifier 2 4 are external to the chip. The models of the differential amplifier 1 3 and the differential amplifier 2 4 include INA180-Q1. INA180-Q1 is the preferred model of the differential amplifier 1 3 and the differential amplifier 2 4. The differential amplifier 1 3 and the differential amplifier 2 4 are not limited to this model, and other models can also be used.

[0018] The gain of differential amplifier 3 is A1, the internal resistance of sampling resistor F1A is R1, and the inverting input and non-inverting input are connected to the two ends of sampling resistor F1A, respectively. The original voltage difference signal across sampling resistor F1A passes through the filter capacitor and current-limiting resistor before entering differential amplifier 3. Differential amplifier 3 amplifies the input original voltage difference signal and transmits it to the ADC channel of processor 5. The voltage collected by the ADC channel of processor 5 is U1. Bus current on the ground path of EPS subsystem 1 If U1 is 0V, the bus current I on the EPS subsystem ground path is BUSA The value is 0A, which means that there is an open circuit fault on the ground path of EPS subsystem 1.

[0019] The gain of differential amplifier 24 is A2, the internal resistance of sampling resistor 2F1B is R2, and the inverting input and non-inverting input are connected to the two ends of sampling resistor 2F1B, respectively. The original voltage difference signal across sampling resistor 2F1B passes through the filter capacitor and current-limiting resistor before entering differential amplifier 24. Differential amplifier 24 amplifies the input original voltage difference signal and transmits it to the ADC channel of processor 26. The voltage collected by the ADC channel of processor 26 is U2. Bus current on the ground path of EPS subsystem 2 If U2 is 0V, the bus current I on the second ground path of the EPS subsystem BUSB The value is 0A, which means that there is an open circuit fault on the ground path of EPS subsystem 2.

[0020] Processor 1 5 and processor 2 6 use the data interaction interface to calculate the I BUSA and I BUSB Compare the values to confirm I BUSA and I BUSB The size and difference of the electric power steering system EPS can be set according to the tolerance of the hardware. BUSA and I BUSB The upper limit of the difference between the two. BUSA and I BUSB When the difference value exceeds the upper limit, such as I BUSAIf the value of is small, it is diagnosed that the impedance of the ground path of EPS subsystem 1 is abnormally increased, which will cause excessive current of EPS subsystem 1 to flow back through the ground of EPS subsystem 2, which exceeds the tolerance of the hardware such as the wiring harness and connectors on the ground path; BUSB If the value is small, it indicates that the impedance of the ground path of EPS subsystem 2 is abnormally increased, which will cause excessive current of EPS subsystem 2 to flow back through the ground of EPS subsystem 1, exceeding the tolerance of hardware such as wiring harnesses and connectors on the ground path.

[0021] This new system connects a sampling resistor in series with the ground line and uses an external differential amplifier to amplify and convert the voltage signal to achieve current detection. Data exchange is achieved through the communication terminals of two processors, enabling real-time and accurate detection and diagnosis of busbar current in the two subsystems of the fully redundant EPS, ensuring stable and reliable operation of the electric power steering system (EPS). This new system offers the advantages of moderate cost, high detection accuracy, and a wide detection range.

Claims

1. A busbar current detection and diagnostic circuit for a fully redundant EPS system, comprising EPS subsystem 1, EPS subsystem 2, a vehicle body ground, and a six-phase motor, characterized by: EPS subsystem 1 includes power supply 1 (1), sampling resistor 1 (F1A), filter capacitor 1 (C1A), filter capacitor 2 (C2A), filter capacitor 3 (C3A), current limiting resistor 1 (R1A), current limiting resistor 2 (R2A), voltage stabilizing capacitor 1 (C4A), differential amplifier 1 (3), processor 1 (5), EPS subsystem 2 includes power supply 2 (2), sampling resistor 2 (F1B), filter capacitor 4 (CAB), filter capacitor 5 (C2B), filter capacitor 6 (C3B), current limiting resistor 3 (R1B), current limiting resistor 4 (R2B), voltage stabilizing capacitor 2 (C4B), differential amplifier 2 (4), processor 2 (6), The positive electrode of power supply 1 (1) is connected to the power supply end of three-phase inverter 1 of six-phase motor (7), the negative electrode of power supply 1 (1) is connected to the vehicle body ground, the No. 4 pin of sampling resistor 1 (F1A) is connected to the vehicle body ground, the No. 2 pin of sampling resistor 1 (F1A) is divided into three paths and respectively connected to one end of filter capacitor 1 (C1A), one end of filter capacitor 2 (C2A) and one end of current limiting resistor 1 (R1A), the other end of current limiting resistor 1 (R1A) is connected to the inverting input end of differential amplifier 1 (3), the non-inverting input end of differential amplifier 1 (3) is connected to one end of current limiting resistor 2 (R2A), the other end of current limiting resistor 2 (R2A) is divided into three paths and respectively connected to the other end of filter capacitor 1 (C1A), filter capacitor 3 (C3 A) and pin 1 of sampling resistor 1 (F1A), the power supply end of differential amplifier 1 (3) is divided into two paths and connected to VCC power supply end 1 and one end of voltage stabilizing capacitor 1 (C4A), the other end of voltage stabilizing capacitor 1 (C4A) is grounded, the ground end of differential amplifier 1 (3), the other end of filter capacitor 2 (C2A), and the other end of filter capacitor 3 (C3A) are connected and then grounded, the output end of differential amplifier 1 (3) is connected to the ADC end of processor 1 (5), the digital end of processor 1 (5) is connected to the control end of three-phase inverter 1 of six-phase motor (7), the positive pole of power supply 2 (2) is connected to the power supply end of three-phase inverter 2 of six-phase motor (7), and the negative pole of power supply 2 (2) is connected to the vehicle body ground, Pin 4 of sampling resistor 2 (F1B) is connected to the vehicle body ground, pin 2 of sampling resistor 2 (F1B) is divided into three paths and connected to one end of filter capacitor 4 (CAB), one end of filter capacitor 5 (C2B) and one end of current limiting resistor 4 (R2B) respectively, the other end of current limiting resistor 4 (R2B) is connected to the inverting input end of differential amplifier 2 (4), the non-inverting input end of differential amplifier 2 (4) is connected to one end of current limiting resistor 3 (R1B), the other end of current limiting resistor 3 (R1B) is divided into three paths and connected to the other end of filter capacitor 4 (CAB), one end of filter capacitor 6 (C3B) and pin 1 of sampling resistor 2 (F1B) respectively, the power supply end of differential amplifier 2 (4) is divided into two paths and connected to VCC The power supply terminal 2 and one end of the voltage stabilizing capacitor 2 (C4B) are connected, the other end of the voltage stabilizing capacitor 2 (C4B) is grounded, the ground end of the differential amplifier 2 (4), the other end of the filter capacitor 5 (C2B), and the other end of the filter capacitor 6 (C3B) are connected and then grounded, the output end of the differential amplifier 2 (4) is connected to the ADC end of the processor 2 (6), the digital end of the processor 2 (6) is connected to the control end of the three-phase inverter 2 of the six-phase motor (7), the data interaction interface of the processor 2 (6) is connected to the data interaction interface of the processor 1 (5), the No. 3 pin of the sampling resistor 1 (F1A), the No. 3 pin of the sampling resistor 2 (F1B), the ground end of the three-phase inverter 1 of the six-phase motor (7), and the ground end of the three-phase inverter 2 are connected and then grounded.

2. The bus current detection and diagnosis circuit for a fully redundant EPS according to claim 1 is characterized in that: The processor 1 (5) and the processor 2 (6) are ECU chips of the electric power steering system EPS.

3. The bus current detection and diagnosis circuit for a fully redundant EPS according to claim 2, characterized in that: The models of the ECU chips include SAL-TC377TP.

4. The bus current detection and diagnosis circuit for a fully redundant EPS according to claim 1 is characterized in that: The models of the differential amplifier 1 (3) and the differential amplifier 2 (4) include INA180-Q1.

5. The bus current detection and diagnosis circuit for a fully redundant EPS according to claim 1 is characterized in that: The EPS subsystem 1 and EPS subsystem 2 are two mutually symmetrical redundant systems.

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