Control device of motor-driven automobile

Abstract

The invention provides a control device of a motor-driven automobile, which comprises a motor for driving wheels of the automobile to rotate; the frequency converter is electrically connected with the motor and used for changing the rotating speed of the motor according to the power supply frequency; the current sensor is used for collecting the current of the motor; the power sensor is used for collecting the power of the motor; the trip computer is in communication connection with the frequency converter, the current sensor and the power sensor and used for controlling the power supply frequency output by the frequency converter and giving an alarm when the current or power of the motor exceeds a threshold value. The motor is controlled through the power supply frequency to drive the wheels of the automobile to rotate, the rotating speed of the motor can be accurately controlled, and therefore the situation that the wheels idle and abrade tires can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of motor drive, and in particular to a control device for a motor-driven vehicle. Background Art

[0002] With the development of new energy vehicles and the application of hybrid vehicles, more and more cars are directly driven by electric motors, but some problems have also been exposed during the use process. For example, due to the good acceleration performance of electric motors, when driving cars in rainy and snowy weather or slippery roads, the wheels are very easy to run empty. The power transmission system of traditional cars is composed of engine operating mechanism, transmission box gears and transmission shafts, and the overall mass is large; and the acceleration performance of fuel engines is also lower than that of electric motors. Therefore, when the driver is operating, even if the wheel driving force is not too large for a short time greater than the friction between the wheel and the road, the empty wheel will not occur immediately (only creep will occur), that is, there is a certain degree of fault tolerance, so this problem is not very prominent. For electric motor-driven cars, because the motor rotor mass is small and the motor has good acceleration performance, it is very easy to run empty when the road is slippery. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, an object of the present invention is to provide a control device for a motor-driven vehicle.

[0004] To achieve the above objectives, the present invention provides the following solutions:

[0005] A control device for a motor-driven vehicle, comprising:

[0006] The motor is used to drive the wheels of the car;

[0007] A frequency converter, electrically connected to the motor, and used to change the motor speed according to the power supply frequency;

[0008] Current sensor, used to collect the current of the motor;

[0009] Power sensor, used to collect the power of the motor;

[0010] The on-board computer is respectively connected to the inverter, the current sensor and the power sensor for controlling the power supply frequency output by the inverter and issuing an alarm when the current or power of the motor exceeds a threshold.

[0011] Preferably, it further comprises: an overcurrent alarm module; the overcurrent alarm module comprises:

[0012] Resistor R, one end of the first resistor R1 is connected to the driving computer;

[0013] A transistor Q, wherein the base of the transistor Q is connected to the other end of the resistor R, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is respectively connected to the cathode of the buzzer H and the anode D of the diode, and the cathode D of the diode is connected to the anode of the buzzer H;

[0014] Capacitor C1, one end of the capacitor C1 is connected to the positive electrode of the buzzer H, and the other end of the capacitor C1 is grounded.

[0015] Preferably, the positive electrode of the buzzer H is connected to the power supply terminal VCC.

[0016] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0017] The present invention provides a control device for a motor-driven vehicle. Compared with the prior art, the present invention controls the motor by power supply frequency to drive the wheels of the vehicle to rotate, thereby achieving precise control of the motor speed, thereby preventing the wheels from spinning idly and causing tire wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 A circuit diagram of an overcurrent alarm module provided by the present invention;

[0020] Figure 2 A working principle diagram of a control device for a motor-driven vehicle provided by the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] The terms "first", "second", "third" and "fourth" in the specification and claims of the present application and the drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a series of steps, processes, methods, etc. are not limited to the listed steps, but may optionally include steps that are not listed, or may optionally include other step elements inherent to these processes, methods, products or devices.

[0024] In order to make the above-mentioned objectives, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] See also Figure 1-2 , a control device for a motor-driven vehicle, comprising:

[0026] The motor is used to drive the wheels of the car;

[0027] A frequency converter, electrically connected to the motor, and used to change the motor speed according to the power supply frequency;

[0028] Current sensor, used to collect the current of the motor;

[0029] Power sensor, used to collect the power of the motor;

[0030] The on-board computer is respectively connected to the inverter, the current sensor and the power sensor for controlling the power supply frequency output by the inverter and issuing an alarm when the current or power of the motor exceeds a threshold.

[0031] According to the principle of AC or variable frequency motor, the synchronous speed of the rotating magnetic field of the motor stator is n=60f / p, where n is the synchronous speed of the rotating magnetic field, f is the power supply frequency, and p is the number of poles of the rotating magnetic field of the motor (the motor structure is determined, p is also determined, and is a constant), and the rotor speed n1 of the motor in the motor working condition is always less than and close to the synchronous speed n. Therefore, when the car accelerator pedal controls the frequency, that is, the wheel speed is given, so when the driver lightly steps on the accelerator pedal on a slippery road, giving the wheel a very small speed, at this time, even if the wheel driving force is slightly greater than the friction between the wheel and the road surface, causing the wheel and the road surface to creep, it will not cause the contact point between the wheel and the road surface to change from relative stillness to idling (because the speed is given), that is, it will not completely destroy the static friction between the wheel and the road surface and turn it into dynamic friction. Since the static friction coefficient is much larger than the dynamic friction coefficient, this ensures the effective drive of the wheel, that is, it gives the driver a certain fault tolerance rate.

[0032] Under normal circumstances, the accelerator pedal is in power control mode to adapt to the driver's driving habits. When the car passes through a slippery road or goes downhill, it can be converted to frequency (speed) control mode. 1. When the frequency (speed) control method is used, the driving computer needs to detect the current and power of the motor at the same time. Because of the characteristics of the motor, at low speed, the large current is easy to exceed the rated current; at high speed, the high power is easy to exceed the rated power. Therefore, the system also needs to limit the motor current at an appropriate time to avoid overcurrent and overpower. 2. When the frequency (speed) control method is used, the acceleration rate of the drive motor should also be controlled according to the difference between the given frequency (speed) and the actual vehicle speed. The greater the difference, the greater the acceleration rate, in order to adapt to the driver's operating habits, but the upper limit of the acceleration rate should also be controlled to avoid the impact of the vehicle on safety; when the energy recovery brake is used on a long downhill slope, the greater the difference between the given frequency (speed) and the actual vehicle speed, the greater the braking force. However, when the accelerator pedal is completely released, if the difference is large, a minimum frequency should be set to avoid the wheels from locking at high speed, which can also improve the stability of the vehicle. Only when the actual vehicle speed is lower than a certain value can the frequency be gradually reduced to 0 according to the vehicle speed.

[0033] Furthermore, the overcurrent alarm module in the present invention comprises:

[0034] Resistor R, one end of the first resistor R1 is connected to the driving computer;

[0035] A transistor Q, wherein the base of the transistor Q is connected to the other end of the resistor R, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is respectively connected to the cathode of the buzzer H and the anode D of the diode, and the cathode D of the diode is connected to the anode of the buzzer H;

[0036] Capacitor C1, one end of the capacitor C1 is connected to the positive electrode of the buzzer H, and the other end of the capacitor C1 is grounded. The positive electrode of the buzzer H is connected to the power supply terminal VCC. When the current or power of the motor exceeds the threshold, the on-board computer sends current to the resistor R to control the transistor Q1 to conduct, so as to complete the power-on of the buzzer H and realize the alarm.

[0037] The present invention controls the motor by power supply frequency to drive the wheels of the car to rotate, and can achieve accurate control of the motor speed, thus preventing the wheels from spinning idly and wearing the tires.

[0038] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the method disclosed in the embodiment, since it corresponds to the device disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the device part description.

[0039] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A control device for a motor-driven vehicle, characterized in that: include: The motor is used to drive the wheels of the car; A frequency converter, electrically connected to the motor, and used to change the motor speed according to the power supply frequency; Current sensor, used to collect the current of the motor; Power sensor, used to collect the power of the motor; The on-board computer is respectively connected to the inverter, the current sensor and the power sensor for controlling the power supply frequency output by the inverter and issuing an alarm when the current or power of the motor exceeds a threshold.

2. A control device for a motor-driven vehicle as claimed in claim 1, characterized in that: Also includes: Overcurrent alarm module; The overcurrent alarm module comprises: A resistor (R), one end of the first resistor (R1) is connected to the on-board computer; A transistor (Q), wherein the base of the transistor (Q) is connected to the other end of the resistor (R), the emitter of the transistor (Q1) is grounded, the collector of the transistor (Q1) is respectively connected to the negative electrode of the buzzer (H) and the anode (D) of the diode, and the cathode (D) of the diode is connected to the positive electrode of the buzzer (H); A capacitor (C1), one end of the capacitor (C1) is connected to the positive electrode of the buzzer (H), and the other end of the capacitor (C1) is grounded.

3. A control device for a motor-driven vehicle as claimed in claim 2, characterized in that: The positive electrode of the buzzer (H) is connected to the power supply terminal (VCC).

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