Default-phase detection method for driving motor of new-energy vehicle

Abstract

The invention discloses a default-phase detection method for a driving motor of a new-energy vehicle. According to the method, in accordance with a motor control principle, when an inverter controls the motor to run, the sum of three phases of currents of the motor is zero,when there is a lack of any phase, the other two phases form a loop, and when there is a lack of any two phases or three phases, no loop can be formed; during static detection, a fixed angle is selected according to the position of a rotor, a specific current vector for guaranteeing that the motor does not apply power is given, three phases of currents are recorded, and whether or not the motor is lack of phases is judged according to a corresponding relationship between the position of the rotor and the currents; afterstatic detection, the vehicle runs for dynamic detection, at this moment, three-phase current values are collected in real time, effective values of the phase currents are calculated, whether or not the motor is lack of phases is judged according to a relationship of the three-phase effective values, and if yes, failure is reported, and the vehicle is controlled to run with lowered power. The default-phase detection method adapts to running working conditions of the new-energy vehicle, the detection accuracy is improved, the situation that the default-phase failure is misreported is avoided, the occurrence of inspection missing is avoided, and reliable running of the motor and a controller is ensured.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a method for detecting lack of phase of a driving motor of a new energy vehicle. Background technique [0002] New energy vehicles have been vigorously promoted due to their high efficiency, energy saving and environmental protection, and have become the development trend of the automobile industry. At the same time, the safety issues of new energy vehicles have gradually attracted widespread attention from the whole society. [0003] The motor and inverter are the core of the new energy vehicle power system. Once a problem occurs, the vehicle will not be able to drive, and it may cause personal injury in severe cases. Usually, the motor and the inverter are connected by a three-phase power line. After long-term use, the joints may become loose and broken due to vibration and corrosion. At the same time, because the motor and inverter need to inject a large current during n...

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Problems solved by technology

[0013] The above methods have high detection accuracy under specific working conditions. However, for new energy vehicles, which have high performance requirements and complex working conditions, it is easy to cause misjudgment or missed detection. For method a, the battery When the voltage is unstable or the torque fluctuates greatly, the bus voltage will fluctuate greatly, which will affect the reliability and accuracy of detection; for method b, the three-phase unbalance is related to the control system, the accuracy of components, and the consistency of the motor. conditions, etc., so it is difficult to use the basis for phase loss detection; for method c, it is generally considered that the motor is in normal operation, a phase current is less than a certain threshold, and a phase loss phenomenon occurs. For single-phase loss Phase has a high judgment accuracy, but when two phases are missing, due to the existence of detection errors, the three-phase currents are relatively small, which is similar to the current when the vehicle is running at a low speed and a constant speed, unless the system has extremely high detection accuracy, otherwise method c cannot be directly applied to new energy vehicle drive motor phase loss fault detection

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