Electric vehicle control system

Abstract

The present invention provides a control system for an electric vehicle, comprising an electric motor, at least one wheel, a speed change mechanism, at least one sensor for sensing the vehicle state of the electric vehicle, and a control unit connected to the at least one sensor by a signal. When the vehicle state is abnormal and meets a first condition set in advance, the control unit switches the speed change mechanism to the first gear, at which time the power motor can still drive the at least one wheel through the speed change mechanism, but the at least one wheel cannot drive the power motor through the speed change mechanism, so when the speed of the at least one wheel is too high due to a downhill or towing situation, the at least one wheel will not drive the power motor to rotate, so that the power motor can be prevented from rotating too high and the generation of back electromotive force can be suppressed.

Description

Technical Field

[0001] The present invention relates to a control system, in particular to a control system for an electric vehicle. Background Art

[0002] Most electric motorcycles today use permanent magnet synchronous motors as their power source, but the speed of this type of motor is proportional to the voltage induced by its three-phase line, thus having a back electromotive force characteristic. In addition to the motor being over-accelerated, when the wheel speed is too high due to special circumstances such as downhill or the vehicle body being dragged, the motor speed will be too fast, resulting in too high back electromotive force. Since the motor controller used to control the motor is usually composed of a metal oxide semiconductor field effect transistor (MOSFET) and a capacitor, when the back electromotive force is too high, the metal oxide semiconductor field effect transistor and the capacitor are prone to overvoltage breakdown and permanent failure. Although there are currently means such as brake recharge or motor weakening to avoid excessive back electromotive force, these means still have failure situations. For example, when the battery is fully charged and the brake recharge is turned off, or when the motor controller is in a power-off state, the above means will not work. Therefore, the current strategy for dealing with excessive motor back electromotive force still has a lot of room for improvement. Summary of the invention

[0003] [Problems to be Solved by the Invention]

[0004] Therefore, an object of the present invention is to provide a control system that can effectively prevent the motor back electromotive force from being too high under various driving conditions.

[0005] [Technical means to solve the problem]

[0006] Therefore, the control system of the electric vehicle of the present invention comprises an electric motor, at least one wheel, a speed change mechanism that can be driven by the power motor and used to drive the at least one wheel, at least one sensor for sensing the vehicle state of the electric vehicle, and a control unit connected to the at least one sensor by signal. The speed change mechanism can be controlled to switch to a first gear position. When the speed change mechanism switches to the first gear position, the power motor can be linked to the at least one wheel through the speed change mechanism, and the at least one wheel cannot be linked to the power motor through the speed change mechanism. When the vehicle state measured by the at least one sensor meets a first condition, the control unit switches the speed change mechanism to the first gear position.

[0007] In some embodiments of the present invention, the speed transmission mechanism can also be controlled to switch to a second gear. When the speed transmission mechanism is switched to the second gear, the power motor can be linked to the at least one wheel through the speed transmission mechanism, and the at least one wheel can also be linked to the power motor through the speed transmission mechanism. When the vehicle state measured by the at least one sensor meets a second condition, the control unit switches the speed transmission mechanism from the first gear to the second gear.

[0008] In some embodiments of the present invention, the at least one sensor can detect the rotation speed of the power motor, and the first condition is that the rotation speed of the power motor is higher than a first threshold.

[0009] In some embodiments of the present invention, the at least one sensor can detect the rotation speed of the power motor, and the first condition is that the rotation speed of the power motor is higher than a first threshold and lasts for more than a first time.

[0010] In some embodiments of the present invention, the at least one sensor can detect the rotation speed of the at least one wheel, and the second condition is that the rotation speed of the at least one wheel is lower than a second threshold.

[0011] In some embodiments of the present invention, the at least one sensor can detect the rotation speed of the at least one wheel, and the second condition is that the rotation speed of the at least one wheel is lower than a second threshold and lasts for more than a second time.

[0012] In some embodiments of the present invention, the speed change mechanism includes an input shaft linked to the power motor, an output shaft linked to the at least one wheel, a reduction gear set arranged on the input shaft and the output shaft, a clutch arranged on the input shaft and controllable to switch the reduction gear set between the first gear and the second gear, and a one-way clutch arranged on the reduction gear set. When the reduction gear set is switched to the first gear, the one-way clutch enables the input shaft to drive the output shaft through the reduction gear set, but the output shaft cannot drive the input shaft through the reduction gear set. When the reduction gear set is switched to the second gear, the input shaft can directly drive the output shaft through the reduction gear set, and the output shaft can also directly drive the input shaft through the reduction gear set.

[0013] In some embodiments of the present invention, the reduction gear set has a first-speed input gear fixed on the input shaft, a second-speed input gear pivotally mounted on the input shaft for relative rotation, a first-speed output gear pivotally arranged relative to the output shaft and meshing with the first-speed input gear, and a second-speed output gear fixed on the output shaft and meshing with the second-speed input gear. The first-speed output gear is sleeved on the second-speed output gear, and the two radially define an annular space for the one-way clutch to be arranged.

[0014] In some embodiments of the present invention, when the reduction gear set is switched to the first gear, the rotating input shaft causes the first gear input gear to drive the first gear output gear to rotate, and drives the second gear output gear and the output shaft to rotate via the one-way clutch, but the rotating output shaft cannot drive the first gear output gear to rotate via the one-way clutch, thereby failing to drive the input shaft; when the reduction gear set is switched to the second gear, the clutch causes the second gear input gear to rotate with the input shaft, and drives the second gear output gear and the output shaft to rotate, and the rotating output shaft can drive the second gear input gear and the input shaft to rotate via the second gear output gear.

[0015] In some embodiments of the present invention, the clutch of the transmission mechanism comprises an outer disc body rotatably pivoted on the input shaft and fixedly connected to the second gear input gear, an inner disc body fixedly arranged on the input shaft corresponding to the outer disc body, a driven disc slidably arranged on the input shaft and located between the outer disc body and the inner disc body, a plurality of pressure plates located between the inner disc body and the driven disc, and a plurality of friction plates staggered with the pressure plates and connected to the outer disc body. When the reduction gear set is switched to the first gear, the driven disc The disc is pressurized and moves away from the inner disc body, so that the friction plates and the pressure plates are spaced apart. Therefore, the inner disc body driven to rotate by the input shaft will not drive the outer disc body and the second-speed input gear. When the reduction gear set switches to the second gear, the driven disc is reset and approaches the inner disc body. The driven disc and the inner disc body cooperate to clamp the friction plates and the pressure plates, so that the friction plates and the pressure plates are tightly pressed against each other. Therefore, the inner disc body driven by the input shaft will drive the outer disc body and the second-speed input gear to rotate through the friction plates and the pressure plates.

[0016] [Effects of the Invention]

[0017] The effect of the present invention is that when the vehicle state is abnormal and meets the pre-set first condition, the control unit will switch the speed change mechanism to the first gear. At this time, the power motor can still drive the at least one wheel through the speed change mechanism, so that the electric vehicle can move forward under the control of the user, but the at least one wheel cannot drive the power motor through the speed change mechanism. Therefore, when encountering a downhill or the electric vehicle is towed and the rotation speed of the at least one wheel is too high, the at least one wheel will not drive the power motor to rotate, thereby avoiding the power motor from rotating too high and suppressing the generation of back electromotive force.

[0018] In some embodiments of the present invention, its function is that when the vehicle state returns to normal and meets the pre-set second condition, the transmission mechanism can be controlled to switch to the second gear, and the second gear allows the power motor and the at least one wheel to drive each other, so that the electric vehicle can restore the original two-way power transmission after escaping from the abnormal speed situation.

[0019] In some embodiments of the present invention, the effect is that the first condition is set as the rotation speed of the power motor is higher than a first threshold and lasts for more than a first time. Switching at this time can prevent the power motor from continuing to increase in speed and exceeding the design upper limit.

[0020] In some embodiments of the present invention, the function is that when it is determined that the rotation speed of the at least one wheel is reduced to a safe range, the second gear can be switched back to restore the transmission mode to a normal preset state.

[0021] In some embodiments of the present invention, its function is that when the reduction gear is switched to the first gear, the one-way clutch will be added to the power transmission chain, and through the characteristics of the one-way clutch, the power motor can drive the at least one wheel in one direction. When the reduction gear is switched to the second gear, the one-way clutch leaves the power transmission chain, so the power motor and the at least one wheel can be bidirectionally linked to each other.

[0022] In some embodiments of the present invention, the one-way clutch is arranged between the first-gear output gear and the second-gear output gear. When the first-gear output gear rotates, the second-gear output gear connected to the output shaft can be driven to rotate by the one-way clutch, and the one-way clutch will not drive the first-gear output gear to rotate when the second-gear output gear rotates, thereby achieving the effect of one-way clutch.

[0023] In some embodiments of the present invention, the clutch can drive the friction plates and the pressure plates to move away from or clamp each other by compressing and resetting the driven disc, thereby switching the reduction gear set between the first gear and the second gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the accompanying drawings, in which:

[0025] Figure 1 is a schematic diagram of an embodiment of a control system for an electric vehicle of the present invention;

[0026] Figure 2 is a top view of a cross-section, illustrating the embodiment of the present invention when the embodiment is switched to a second gear position;

[0027] Figure 3 is a schematic diagram illustrating an electric vehicle in this embodiment;

[0028] Figure 4 is a top view of a cross-section illustrating the embodiment of the present invention when the embodiment is switched to a first gear position; and

[0029] Figure 5 is a flow chart illustrating the operation of this embodiment.

[0030] Reference numerals list

[0031] 1····Power motor

[0032] 2. Wheels

[0033] 3. Speed ​​Shifting Mechanism

[0034] 31···Input shaft

[0035] 32···Output shaft

[0036] 33···Reduction gear set

[0037] 331···First gear input gear

[0038] 332···2nd gear input gear

[0039] 333···1st gear output gear

[0040] 334···2nd gear output gear

[0041] 335···Annular Space

[0042] 34···One-way clutch

[0043] 35···Clutch

[0044] 351···Outer disk

[0045] 352···Inner disc

[0046] 353···Driven disc

[0047] 354···Press plate

[0048] 355···Friction plate

[0049] 356···Spring

[0050] 36···Push piece

[0051] 361···Promotion

[0052] 362···Ejector rod

[0053] 37···Drive rod

[0054] 4. Sensors

[0055] 5. Control unit

[0056] 61···Frame unit

[0057] 62···Battery Cell

[0058] 63···Motor controller. DETAILED DESCRIPTION

[0059] See also Figure 1 , Figure 2 ,and Figure 3 An embodiment of the control system of the electric vehicle of the present invention comprises a power motor 1, two wheels 2 located at the front and rear, a speed change mechanism 3 matched with the power motor 1 and the wheel 2 located at the rear, two sensors 4 respectively used to monitor the power motor 1 and the wheel 2 located at the front, and a control unit 5 connected to the sensors 4 and capable of controlling the speed change mechanism 3. The power motor 1 is mounted on a frame unit 61, and is operated by a battery unit 62 to provide power, and is controlled by a motor controller 63 (MCU).

[0060] The speed change mechanism 3 includes an input shaft 31 linked to the power motor 1, an output shaft 32 linked to the rear wheel 2, a reduction gear set 33 provided on the input shaft 31 and the output shaft 32, a one-way clutch 34 provided on the reduction gear set 33, a clutch 35 provided on the input shaft 31, a push piece 36 linked to the clutch 35, and a driving rod 37 for driving the push piece 36. The reduction gear set 33 includes a first-gear input gear 331 fixed to the input shaft 31, a second-gear input gear 332 pivotally provided on the input shaft 31 for relative rotation, a first-gear output gear 333 pivotally provided relative to the output shaft 32 and meshed with the first-gear input gear 331, and a second-gear output gear 334 fixed to the output shaft 32 and meshed with the second-gear input gear 332. The first gear output gear 333 is sleeved on the second gear output gear 334, and the two define an annular space 335 along the radial direction. The one-way clutch 34 is disposed in the annular space 335, and can drive the second gear output gear 334 to rotate synchronously when the first gear output gear 333 rotates, but when the second gear output gear 334 rotates, the one-way clutch 34 will not drive the first gear output gear 333, thereby achieving the effect of one-way clutch. The clutch 35 comprises an outer disc 351 rotatably pivoted on the input shaft 31 and fixedly connected to the second gear input gear 332, an inner disc 352 fixedly arranged on the input shaft 31 corresponding to the outer disc 351, a driven disc 353 slidably arranged on the input shaft 31 and located between the outer disc 351 and the inner disc 352, a plurality of pressure plates 354 located between the inner disc 352 and the driven disc 353, and a plurality of friction plates 355 staggered with the pressure plates 354 and connected to the outer disc 351. The push member 36 comprises a push pin 361 that can be linked to the driven disc 353 and can be pushed along the input shaft 31, and a push rod 362 axially inserted into the input shaft 31 and can push the push pin 361. The drive rod 37 extends in the up-down direction and is driven to rotate by a motor or other power element.

[0061] See also Figure 1 , Figure 2 ,and Figure 4 The speed change mechanism 3 can be controlled to Figure 4 The first gear shown and Figure 2 When the drive rod 37 is driven by a power source such as a motor to rotate to the second gear position shown in FIG. Figure 4In the position shown, that is, when switched to the first gear, the driving rod 37 will push the ejector rod 362 inward to make it move axially in the input shaft 31, and at the same time, the ejector rod 362 will also push the push pin 361 to move together. Since the push pin 361 is linked to the driven disk 353, the driven disk 353 will also be driven, causing the driven disk 353 to move away from the inner disk body 352 and approach the outer disk body 351. In addition to compressing the spring 356 between the driven disk 353 and the inner disk body 352, the aforementioned action will also allow the pressure plates 354 and the friction plates 355 located between the driven disk 353 and the inner disk body 352 to be spaced apart from each other. In this way, when the input shaft 31 is driven to rotate by the power motor 1, the inner disk body 352 fixed on the input shaft 31 will rotate accordingly, but the pressure plates 354 and the friction plates 355 connected to the outer disk body 351 will not rotate accordingly, so the outer disk body 351 and the second gear input gear 332 connected to the outer disk body 351 will not be driven. At this time, only the first gear input gear 331 fixedly connected to the input shaft 31 will rotate, and drive the first gear output gear 333 meshing therewith to rotate, and finally the first gear output gear 333 drives the second gear output gear 334 to rotate synchronously through the one-way clutch 34, so that the output shaft 32 fixedly arranged with the second gear output gear 334 can be driven to rotate, thereby driving the rear wheel 2 to rotate. In the first gear position, if the rear wheel 2 drives the output shaft 32 to rotate, the second gear output gear 334 that rotates along with it will not be able to drive the first gear output gear 333 to rotate through the one-way clutch 34, and thus the power motor 1 cannot be driven to rotate through the wheel 2.

[0062] When the driving rod 37 is driven by a power source such as a motor to rotate to a certain Figure 2In the position shown, that is, when the second gear is switched, the driving rod 37 no longer pushes the push rod 362 and the push rod 361 inward, so the spring 356 between the driven plate 353 and the inner plate body 352 is no longer compressed and releases the elastic potential energy, which makes the driven plate 353 close to the inner plate body 352 and away from the outer plate body 351, and the driven plate 353 and the inner plate body 352 cooperate to clamp the pressure plates 354 and the friction plates 355, and the pressure plates 354 and the friction plates 355 that are tightly pressed against each other will rotate together due to the friction force, so that the inner plate body 352 that rotates with the input shaft 31 can be linked to the outer plate body 351 through the friction plates 355 to rotate synchronously, thereby rotating the second gear input gear 332. The second gear input gear 332 will drive the meshing second gear output gear 334 to rotate, and finally the output shaft 32 will rotate to drive the wheel 2 located at the rear. It should be noted that, in the aforementioned process, the first gear input gear 331 will also drive the first gear output gear 333 to rotate, but the one-way clutch 34 will prevent the first gear output gear 333 from driving the second gear output gear 334 to avoid mutual interference between the two. On the other hand, in the second gear, since the power transmission does not directly pass through the one-way clutch 34, the power motor 1 can drive the wheel 2 according to the aforementioned actuation sequence, and the wheel 2 can also drive the power motor 1 in the reverse sequence.

[0063] See also Figure 1 , Figure 2 ,and Figure 5 In this embodiment, the sensors 4 monitor the rotation speed of the power motor 1 and the wheel speed of the front wheel 2 (converted to the vehicle speed here). The control unit 5 is a vehicle controller (VCU) that can be used to control the motor to drive the drive rod 37 to rotate. The operation flow of the control system is as follows: Figure 4As shown, when the electric vehicle is running, if the speed of the power motor 1 is higher than a first threshold value and lasts for more than a first time, the control unit 5 will drive the drive rod 37 to rotate so that the speed change mechanism 3 is switched to the first gear. By means of the one-way transmission characteristics of the one-way clutch 34 as described above, the power motor 1 can continuously drive the rear wheel 2 to rotate, but the wheel 2 will not drive the power motor 1, so that the speed of the power motor 1 is prevented from being too high and the motor controller 63 is prevented from being over-voltage-broken. In this embodiment, the first threshold value is about 12000RPM (about 120 kilometers per hour), and the first time is about 0.1 seconds to 2 seconds. When the corresponding sensor 4 detects that the speed of the front wheel 2 is lower than a second threshold value and lasts for more than a second time, the control unit 5 drives the drive rod 37 to rotate so that the speed change mechanism 3 is switched back to the second gear. At this time, not only the power motor 1 can drive the rear wheel 2, but the wheel 2 can also drive the power motor 1 to return to a normal driving state. In this embodiment, the second threshold is approximately 95 kilometers per hour, and the second time is approximately 0.1 seconds to 2 seconds.

[0064] It should be noted that the aforementioned first and second thresholds and the first and second times can be adjusted according to the actual performance of the electric vehicle and consumer demand, and are not limited to the aforementioned parameters, and the sensor 4 that monitors the front wheel 2 can also monitor the rear wheel 2. On the other hand, this embodiment can also monitor other vehicle states of the electric vehicle by other sensors 4, and set a first condition that needs to switch to the first gear, and a second condition that can switch to the second gear to restore the normal driving state, so as to establish a protection mechanism to prevent the power motor 1 from over-speeding according to different needs, and has considerable design flexibility. More importantly, this embodiment is not only suitable for general vehicles going downhill or being towed, but can also operate normally when the battery unit 62 is fully charged or the motor controller 63 is powered off.

[0065] In summary, the present invention can switch the speed change mechanism 3 to the first gear by the control unit 5 when the rotation speed of the power motor 1 exceeds the first threshold value and lasts for the first time, so that the power motor 1 can drive the wheel 2 located at the rear by the one-way clutch 34, and the wheel 2 cannot drive the power motor 1 by the one-way clutch 34. In this way, the rotation speed of the power motor 1 can be prevented from continuously increasing and exceeding the design upper limit, thereby preventing the back electromotive force of the power motor 1 from being too high and causing overvoltage breakdown, so the purpose of the present invention can be achieved.

[0066] The above descriptions are merely embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. All simple equivalent changes and modifications made according to the claims and description of the present invention are still within the scope of the present invention.

Claims

1. A control system for an electric vehicle, characterized in that: Include: a power motor; At least one wheel; a transmission mechanism, which can be driven by the power motor and used to drive the at least one wheel, the transmission mechanism can be controlled to switch to a first gear position, when the transmission mechanism is switched to the first gear position, the power motor can be linked to the at least one wheel through the transmission mechanism, and the at least one wheel cannot be linked to the power motor through the transmission mechanism, the transmission mechanism can also be controlled to switch to a second gear position, when the transmission mechanism is switched to the second gear position, the power motor can be linked to the at least one wheel through the transmission mechanism, and the at least one wheel can also be linked to the power motor through the transmission mechanism; At least one sensor for sensing the vehicle status of the electric vehicle; and A control unit is signal-connected to the at least one sensor. When the vehicle state measured by the at least one sensor meets a first condition, the control unit switches the transmission mechanism to the first gear. When the vehicle state measured by the at least one sensor meets a second condition, the control unit switches the transmission mechanism from the first gear to the second gear.

2. The control system of the electric vehicle according to claim 1, characterized in that: The at least one sensor can detect the rotation speed of the power motor, and the first condition is that the rotation speed of the power motor is higher than a first threshold.

3. The control system of the electric vehicle according to claim 1, characterized in that: The at least one sensor can detect the rotation speed of the power motor, and the first condition is that the rotation speed of the power motor is higher than a first threshold and lasts for more than a first time.

4. The control system of the electric vehicle according to claim 1, characterized in that: The at least one sensor can detect the rotation speed of the at least one wheel, and the second condition is that the rotation speed of the at least one wheel is lower than a second threshold.

5. The control system of the electric vehicle according to claim 1, characterized in that: The at least one sensor can detect the rotation speed of the at least one wheel, and the second condition is that the rotation speed of the at least one wheel is lower than a second threshold and lasts for more than a second time.

6. The control system of the electric vehicle according to claim 1, characterized in that: The speed change mechanism includes an input shaft linked to the power motor, an output shaft linked to at least one wheel, a reduction gear set arranged on the input shaft and the output shaft, a clutch arranged on the input shaft and controllable to switch the reduction gear set between the first gear and the second gear, and a one-way clutch arranged on the reduction gear set. When the reduction gear set is switched to the first gear, the one-way clutch enables the input shaft to drive the output shaft through the reduction gear set, but the output shaft cannot drive the input shaft through the reduction gear set. When the reduction gear set is switched to the second gear, the input shaft can directly drive the output shaft through the reduction gear set, and the output shaft can also directly drive the input shaft through the reduction gear set.

7. The control system of the electric vehicle according to claim 6, characterized in that: The reduction gear set comprises a first-speed input gear fixed on the input shaft, a second-speed input gear pivotally mounted on the input shaft for relative rotation, a first-speed output gear pivotally arranged relative to the output shaft and meshing with the first-speed input gear, and a second-speed output gear fixed on the output shaft and meshing with the second-speed input gear. The first-speed output gear is sleeved on the second-speed output gear, and the two define an annular space in the radial direction for the one-way clutch to be arranged.

8. The control system of the electric vehicle according to claim 7, characterized in that: When the reduction gear set is switched to the first gear, the rotating input shaft causes the first gear input gear to drive the first gear output gear to rotate, and the second gear output gear and the output shaft are rotated in conjunction with the one-way clutch, but the rotating output shaft cannot drive the first gear output gear to rotate through the one-way clutch, thereby failing to drive the input shaft. When the reduction gear set is switched to the second gear, the clutch causes the second gear input gear to rotate with the input shaft, and drives the second gear output gear and the output shaft to rotate, and the rotating output shaft can drive the second gear input gear and the input shaft to rotate through the second gear output gear.

9. The control system of the electric vehicle according to claim 8, characterized in that: The clutch of the transmission mechanism comprises an outer disc body rotatably pivoted on the input shaft and fixedly connected to the second gear input gear, an inner disc body fixedly arranged on the input shaft corresponding to the outer disc body, a driven disc slidably arranged on the input shaft and located between the outer disc body and the inner disc body, a plurality of pressure plates located between the inner disc body and the driven disc, and a plurality of friction plates staggered with the pressure plates and connected to the outer disc body. When the reduction gear set is switched to the first gear, the driven disc is pressed and moves away from the The inner disc body separates the friction plate and the pressure plate, so the inner disc body driven by the input shaft to rotate will not drive the outer disc body and the second-speed input gear. When the reduction gear set switches to the second gear, the driven disc is reset and approaches the inner disc body. The driven disc and the inner disc body cooperate to clamp the friction plate and the pressure plate, so that the friction plate and the pressure plate are tightly pressed against each other. Therefore, the inner disc body driven by the input shaft will drive the outer disc body and the second-speed input gear to rotate through the friction plate and the pressure plate.

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