Speed command generation unit and speed command generation method for an electric vehicle

Abstract

The present invention provides a speed command generation unit and a speed command generation method for an electric vehicle. The speed command generation unit for an electric vehicle is applied to an electric vehicle and includes a calculation module that can generate a calculated value of a speed command based on an accelerator signal, a sensing module that can detect the actuation state of the mechanical brake of the electric vehicle, a selection module that can selectively provide a brake mode selection signal, a trimming module that can set a trimming flag based on the actuation state of the mechanical brake in the previous cycle, and a switching module that connects the foregoing modules. When the mechanical brake is not actuated in the present cycle, the switching module generates an output value of the speed command on different bases according to the content of the trimming flag, and when the mechanical brake is actuated in the present cycle, generates an output value of the speed command based on the brake mode selection signal, and the switching module outputs the output value to the motor of the electric vehicle.

Description

Technical Field

[0001] The present invention relates to an electric vehicle, and particularly to a speed command generation unit and a speed command generation method applied to an electric vehicle. Background Art

[0002] At present, electric vehicles on the market can be mainly divided into two architectures: torque control and speed control. Generally speaking, civilian vehicles (such as electric motorcycles) mainly adopt the torque control architecture because the requirements are relatively simple. In contrast, industrial vehicles (such as forklifts) need a relatively stable speed during use, and some industrial vehicles also need to have a decelerating braking force when the driver releases the accelerator, so they mostly adopt the speed control architecture to achieve this.

[0003] Generally speaking, industrial vehicles still have certain basic requirements for maneuverability and ride comfort. However, due to cost considerations, the transmission system and suspension system of industrial vehicles are relatively simple compared to civilian vehicles. Therefore, how to improve the control technology to make up for the congenital deficiencies in the structure of industrial vehicles to meet the driver's maneuverability and riding comfort is an important issue for each manufacturer.

[0004] Please refer to Figure 1 , which is a schematic diagram of a speed command generation unit in related technologies. As Figure 1 shown, in a common speed control architecture, the speed command input value 11 and the previous calculated value 12 are continuously input into the speed command unit 10, so that the speed command unit 10 calculates and outputs the corresponding speed command output value 13. Moreover, during periodic control, this speed command output value 13 is used as the previous calculated value 12 and then input into the speed command unit 10 again.

[0005] However, the speed command unit 10 adopted in related technologies mainly only has basic acceleration, deceleration, and S-curve functions. In such a control architecture, when the driver actuates the mechanical brake of the electric vehicle, the speed command unit 10 cannot know it, so it will not immediately provide braking torque to cooperate. And when the driver steps on the accelerator hard to accelerate, or makes the electric vehicle perform heavy load or climb, the throttle signal (corresponding to the speed command input value 11) may be temporarily invalid due to torque saturation. When the above situations occur, the driver will temporarily lose control of the movement behavior of the electric vehicle, thus causing an accident. Summary of the Invention

[0006] The main purpose of the present invention is to provide a speed command generation unit and a speed command generation method for an electric vehicle, which can switch or trim the speed command based on the actuation state of the mechanical brake of the electric vehicle and the way of using the recovery brake.

[0007] To achieve the above object, the speed command generation unit of the present invention is applied to a driver of an electric vehicle. The driver is used to drive a motor of the electric vehicle, and the speed command generation unit includes: an accelerator module that calculates a set value of a speed command according to an accelerator operation signal generated by an external operation; a calculation module that generates a calculated value of the speed command based on the set value; a mechanical brake sensing module that continuously detects an actuation state of a mechanical brake of the electric vehicle; a brake mode selection module; a trimming module connected to the mechanical brake sensing module and the calculation module, wherein the trimming module sets a trimming flag to Disable when the mechanical brake was not actuated during the previous sampling, and sets the trimming flag to Enable when the mechanical brake was actuated during the previous sampling; and

[0008] a switching module connected to the calculation module, the mechanical brake sensing module, the brake mode selection module and the trimming module. When the mechanical brake sensing module samples that the mechanical brake is not actuated and the trimming flag is Disable during the current sampling, it uses the calculated value as a basis to generate an output value of the speed command to drive and control the motor. When the mechanical brake sensing module samples that the mechanical brake is not actuated and the trimming flag is Enable during the current sampling, it uses the current motor speed of the motor as a basis to generate the output value of the speed command to drive and control the motor. And when the mechanical brake sensing module samples that the mechanical brake is actuated during the current sampling, it switches the brake mode based on a brake mode selection signal provided by the brake mode selection module, and uses the brake mode selection signal as a basis to generate the output value of the speed command to drive and control the motor.

[0009] To achieve the above object, the speed command generation method of the present invention is applied to a driver of an electric vehicle. The driver is used to drive a motor of the electric vehicle. The driver includes a speed command generation unit. The speed command generation unit calculates a set value of a speed command according to an accelerator signal and generates a calculated value of the speed command based on the set value. The speed command generation method includes:

[0010] a) Continuously detecting an actuation state of a mechanical brake of the electric vehicle.

[0011] b) Setting a trimming flag according to the actuation state during the previous sampling, wherein when the trimming flag is Disable, it means that the mechanical brake was not actuated during the previous sampling, and when the trimming flag is Enable, it means that the mechanical brake was actuated during the previous sampling.

[0012] c) When it is determined in step a) that the mechanical brake is not actuated during the current sampling and the trimming flag is set to Disable in step b), using the calculated value of the speed command during the current sampling as a basis to generate an output value of the speed command.

[0013] d) When it is determined in step a) that the mechanical brake is not actuated during this sampling, and when it is set in step b) that the trimming flag is enabled, use the current motor speed of the motor as a basis to generate the output value of the speed command.

[0014] e) After step c) or step d), output the output value to the motor to drive and control the motor.

[0015] f) When it is determined in step a) that the mechanical brake is actuated during this sampling, switch the braking mode based on a braking mode selection signal, and use the braking mode selection signal as a basis to generate the output value of the speed command to drive and control the motor.

[0016] Compared with the related art, the present invention at least switches or trims the output value of the speed command based on the actuation state of the mechanical brake on the electric vehicle and the way of using the regenerative brake, thereby effectively solving the problem that when the driver generally actuates the mechanical brake, the system may temporarily lose control of the movement behavior of the electric vehicle because it fails to promptly know the driver's operation. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of a speed command generation unit of the related art.

[0018] Figure 2 It is a schematic diagram of an electric vehicle using a multi-motor system of the present invention.

[0019] Figure 3 It is a block diagram of a speed command generation unit according to a first specific embodiment of the present invention.

[0020] Figure 4 It is a flowchart of a speed command generation method according to a first specific embodiment of the present invention.

[0021] Figure 5 It is a schematic diagram of the torque command upper limit according to a first specific embodiment of the present invention.

[0022] Figure 6 It is a flowchart of a speed command generation method according to a second specific embodiment of the present invention.

[0023] Figure 7A and Figure 7B It is a schematic diagram of speed command optimization according to a first specific embodiment of the present invention.

[0024] Figure 8A and Figure 8B It is a schematic diagram of speed command optimization according to a second specific embodiment of the present invention.

[0025] Figure 9A and Figure 9BSchematic diagram of speed command optimization for the third specific embodiment of the present invention.

[0026] The reference numerals are as follows:

[0027] 10…Speed command unit

[0028] 11…Speed command input value

[0029] 12…Previous calculated value

[0030] 13…Speed command output value

[0031] 21…First driver

[0032] 22…First sensor

[0033] 23…First peripheral controller

[0034] 24…First motor

[0035] 31…Second driver

[0036] 32…Second sensor

[0037] 33…Second peripheral controller

[0038] 34…Second motor

[0039] 41…Instrument

[0040] 42…Battery

[0041] 43…Switch

[0042] 44…Relay

[0043] 51…Throttle module

[0044] 52…Calculation module

[0045] 53…Mechanical brake sensing module

[0046] 54…Brake mode selection module

[0047] 55…Switching module

[0048] 56…Trimming module

[0049] 57…Waiting module

[0050] 61…Set value

[0051] 62…Calculated value

[0052] 63…Output value

[0053] 64…Previous calculated value

[0054] 65…Actuation state

[0055] 66…Motor speed

[0056] 67…Torque command

[0057] 71…Controller

[0058] 72…Torque limit form

[0059] 81, 91…Motor speed

[0060] 82, 92…Speed command

[0061] 83, 93…Torque

[0062] S10~S24, S30~S46…Command generation steps Detailed implementation manners

[0063] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0064] The present invention discloses a speed command generation unit for an electric vehicle, and the speed command generation unit is mainly applied to the driver of any electric vehicle (such as a stacker, an electric motorcycle, an electric vehicle, etc.). Specifically, the speed command generation unit of the present invention is mainly implemented in the form of software or firmware, and the driver can switch or trim the speed command through logical judgment when the driver actuates the mechanical brake, steps on the accelerator heavily to accelerate, or makes the electric vehicle carry heavy loads or climb slopes. Thereby, the problem that the driver of the existing electric vehicle is prone to temporarily lose control of the movement behavior of the electric vehicle when the driver performs the above operations is solved.

[0065] Refer to Figure 2 , which is a schematic diagram of an electric vehicle using a multi-motor system of the present invention. Generally speaking, an electric vehicle can be divided into a single-motor system that uses a single driver to control a single motor, and a multi-motor system that uses at least one driver to control a plurality of motors. Figure 2 The embodiment of

[0066] As shown in Figure 2As shown in the figure, inside an electric vehicle, there may be a first driver 21, a first sensor 22 that senses specific data and provides it to the first driver 21, a first peripheral controller 23 that controls the first driver 21 according to specific information, and a first motor 24 that receives a speed command or a torque command from the first driver 21 and is driven to rotate. In a multi-motor system, inside the same electric vehicle, there may also be a second driver 31 independent of the first driver 21, a second sensor 32 that senses specific data and provides it to the second driver 31, a second peripheral controller 33 that controls the second driver 31 according to specific information, and a second motor 34 that receives a speed command or a torque command from the second driver 31 and is driven to rotate.

[0067] Generally speaking, the first motor 24 rotates under the control of the first driver 21, and the second motor 34 rotates under the control of the second driver 31. The rotations of the first motor 24 and the second motor 34 can theoretically be independent of each other without interference. In the present invention, the speed command generating unit can be configured in the first driver 21 or the second driver 31 in the form of software or firmware, or can be configured in both the first driver 21 and the second driver 31 simultaneously and operate independently, but it is not limited thereto.

[0068] As Figure 2 shown in the figure, the electric vehicle may also have a meter 41 that connects the first driver 21 and the second driver 31 to receive motor information and display it for the driver to read. In addition, the electric vehicle has a battery 42 to provide power for the system operation. The battery 42 is connected to the first driver 21 and the second driver 31 through a switch 43. When the switch 43 is turned on (for example, after the driver starts the electric vehicle with a key), the first driver 21 and the second driver 31 receive the power from the battery 42 and start, and can generate a speed command or a torque command for controlling the first motor 24 / second motor 34 according to the throttle signal generated based on the driver's manipulation of the throttle unit (not shown in the figure) and the speed command generating unit of the present invention. In addition, the battery 42 can also be connected to the first driver 21 and the second driver 31 through a relay 44 to adjust or convert the power provided by the battery 42 through the relay 44.

[0069] Continuing to refer to Figure 3 , it is a block diagram of the speed command generating unit of the first specific embodiment of the present invention. As Figure 3As shown in the figure, based on the functions to be executed, the speed command generation unit in this case can be divided into multiple functional modules that can operate independently or in cooperation, including at least a throttle module 51, a calculation module 52, a mechanical brake sensing module 53, a brake mode selection module 54, a switching module 55, and a trimming module 56. It should be noted that the above modules include software modules implemented by program codes, and physical modules such as circuits used to connect to physical components on the electric vehicle, but are not limited thereto.

[0070] The throttle module 51 is mainly used to connect to the physical throttle unit (not shown in the figure) on the electric vehicle, and generate corresponding throttle operation signals based on the external operations applied by the driver on the throttle unit (such as stepping on the throttle pedal or turning the throttle grip). In an embodiment, the speed command generation unit directly generates the output value 63 of the speed command based on the driver's operation on the throttle unit (that is, there is no need to switch or trim the speed command). Therefore, the throttle module 51 can directly use the throttle operation signal as the set value 61 of the speed command.

[0071] The calculation module 52 is connected to the throttle module 51, used to receive the set value 61 from the throttle module 51, and provide the calculated value 62 of the speed command based on the set value 61. In an embodiment, the calculation module 52 is similar to the speed controller used in the related art (that is, having basic acceleration and deceleration functions and S-zone line functions), which will not be elaborated here.

[0072] During the periodic detection process and when there is no need to switch or trim the speed command, after outputting the calculated value 62, the calculation module 52 will use the calculated value 62 as the previous calculated value 64 and then transmit it back to the input end of the calculation module 52 to generate the calculated value 62 of the next cycle based on the set value 61 and the previous calculated value 64.

[0073] The mechanical brake sensing module 53 can mainly be a physical module, used to periodically detect the actuation state of the mechanical brake (not shown in the figure) of the electric vehicle during the operation of the electric vehicle. When the mechanical brake is actuated, it means that the driver has actively performed a braking action; when the mechanical brake is not actuated, it means that the driver has no intention of actively braking.

[0074] In an embodiment, the mechanical brake sensing module 53 can be a mechanical detector that has a direct contact relationship with the mechanical brake of the electric vehicle (such as a brake switch set under the brake pedal), or an electronic detector that does not directly contact the mechanical brake (such as a light sensor that judges the depth of the brake pedal through a light interruption signal). However, the above is only one specific implementation manner of the present invention, but is not limited thereto.

[0075] The speed command generation unit of the present invention is mainly applied to electric vehicles powered by batteries, and some electric vehicles further have a motor regenerative braking assist function. Such technologies are also known as energy recovery brake function, kinetic energy recovery system (KERS) function, or regenerative braking function, which vary depending on the respective technologies and naming of manufacturers. It mainly refers to the related technologies that can recover electrical energy through kinetic energy when the motor brakes, which will not be elaborated here. In an embodiment, the braking mode selection module 54 can be a software module or a physical module (such as a graphical interface on an electric vehicle) for the driver to operate and select whether to activate the motor regenerative braking assist function.

[0076] Specifically, the braking mode selection module 54 can generate and provide a corresponding braking mode selection signal after the driver selects a braking mode. For example, when the motor regenerative braking assist function is turned on, it outputs the signal "1", indicating a regenerative braking demand; when the motor regenerative braking assist function is not turned on, it outputs the signal "0", indicating no regenerative braking demand. When the mechanical brake is detected to be actuated during the operation of the electric vehicle, the switching module 55 can then switch the braking mode of the electric vehicle based on the braking mode selection signal provided by the braking mode selection module 54 (i.e., perform motor regenerative braking assist or not perform motor regenerative braking assist).

[0077] The switching module 55 is mainly a software module and is connected to the calculation module 52, the mechanical brake sensing module 53, and the braking mode selection module 54. The switching module 55 is used to determine whether to switch or trim the output value 63 of the speed command based on the actuation state 65 of the mechanical brake of the electric vehicle, thereby avoiding the problem that the driver may briefly lose control of the movement behavior of the electric vehicle when actuating / releasing the mechanical brake.

[0078] As Figure 3 shown, the switching module 55 mainly receives the calculated value 62 of the speed command from the calculation module 52, receives the actuation state 65 of the mechanical brake from the mechanical brake sensing module 53, receives the braking mode selection signal from the braking mode selection module 54, and receives the currently detected motor speed 66 of the motor (such as Figure 2 the first motor 24 and / or the second motor 34 shown).

[0079] In the first embodiment, when the switching module 55 samples this time (i.e., this detection cycle), the mechanical brake is not actuated (i.e., the mechanical brake actuation state 65 indicates that the mechanical brake is not actuated), and when a trimming mark is set to the first content, it is determined that the driver does not use the mechanical brake. At this time, the switching module 55 directly uses the calculated value 62 provided by the calculation module 52 as a basis to generate an output value 63 of the speed command. In other words, the switching module 55 can directly use this calculated value 62 as the output value 63 and output it to the motor to drive and control the motor. In this embodiment, the switching module 55 does not perform any processing on the output value 63 of the speed command. In this embodiment, the first content can be, for example, Disable or the parameter "0" for easy software interpretation.

[0080] In the second embodiment, when the switching module 55 samples this time and the mechanical brake is not actuated, and when the trimming mark is set to the second content (different from the aforementioned first content), it is determined that the actuation state of the mechanical brake has changed. At this time, the switching module 55 uses the current motor speed 66 of the motor as a basis to trim the speed command to generate an output value 63 of the speed command. In other words, the switching module 55 can directly use the current motor speed 66 of the motor as the output value 63 and output it to the motor to drive and control the motor. In this embodiment, the second content can be, for example, Enable or the parameter "1".

[0081] In this embodiment, the switching module 55 makes the motor speed 66 and the output value 63 of the speed command consistent with each other, thereby avoiding discomfort caused by the inconsistency between the speed command and the actual motor speed 66.

[0082] In the third embodiment, when the mechanical brake is actuated during this sampling by the switching module 55, the braking mode is switched based on the braking mode selection signal (i.e., perform motor recovery braking assistance or not perform motor recovery braking assistance). And the switching module 55 uses the braking mode selection signal as a basis to generate an output value 63 of the speed command. Specifically, when the motor recovery braking assistance function is activated, the electric vehicle can obtain additional braking force other than the existing mechanical brake through the reverse torque during motor deceleration control, making it easier to control the electric vehicle to decelerate and reducing the burden on the mechanical brake (e.g., reducing the wear of the brake pads); if the motor recovery braking assistance function is not activated, the electric vehicle only decelerates by the driver's operation of the mechanical brake. Since the total braking force of the electric vehicle is different when the motor recovery braking assistance function is activated / not activated, the switching module 55 needs to perform additional processing on the output value 63 of the speed command to achieve smooth driving.

[0083] In this embodiment, the switching module 55 mainly generates an output value 65 of the speed command based on the current motor speed 66 of the motor when the mechanical brake in this sampling is actuated and the brake mode selection signal indicates that the motor boost brake assist function is not actuated. In other words, the switching module 55 can directly use the current motor speed 66 of the motor as the output value 63 and output it to the motor to drive and control the motor. At this time, since the speed command is adjusted to be the same as the actual motor speed 66, the driver will not have torque output. In this state, the motor does not output any power at all, and braking is completely performed by the driver's operation of the mechanical brake, which makes the deceleration control easier to execute and avoids excessive wear of the mechanical brake (for example, part of the braking force is used to resist the motor torque).

[0084] In addition, when the mechanical brake in this sampling is actuated and the brake mode selection signal indicates that the motor boost brake assist function is actuated, the switching module 55 changes to use a zero speed command as the basis to generate an output value 65 of the speed command. In other words, the switching module 55 can directly use the zero speed command as the output value 63 and output it to the motor to drive and control the motor. At this time, since the speed command is zero, the driver will calculate and output a relatively large reverse torque to the motor for deceleration. In this state, the electric vehicle can achieve the purpose of deceleration by the reverse torque of the motor boost brake and the braking force of the mechanical brake at the same time, which makes the deceleration control easier to execute and avoids excessive wear of the mechanical brake (for example, the reverse torque provided by the motor assists to reduce the mechanical brake force).

[0085] The trimming module 56 is mainly used to mark the actuation state 65 of the mechanical brake detected in the previous cycle to determine whether to perform a trimming process on the calculated output value 63 of the speed command before outputting it this time. As Figure 3 shown, the trimming process in the present invention refers to determining whether to input the previous calculated value 64 to the calculation module 52 so that the switching module 55 generates the output value 63 based on the normal calculated value 62 (that is, not trimming the output value 63), or determining whether to input the current motor speed 66 to the calculation module 52 so that the switching module 55 generates the output value 63 based on the motor speed 66 (that is, trimming the original output value 63 to another output value 63 that is the same as the motor speed 66).

[0086] The trimming module 56 is mainly connected to the mechanical brake sensing module 53 and the calculation module 52, and the trimming module 56 can receive the actuation state 65 of the mechanical brake from the mechanical brake sensing module 53. In one embodiment, when the mechanical brake was not actuated in the previous sampling, the trimming module 56 sets the trimming mark to the first content ( Figure 3is presented with the mark "0", indicating that the decision for the trimming process is in a disabled state. In another embodiment, when the mechanical brake was actuated during the previous sampling, the trimming module 56 sets the trimming mark to a second content ( Figure 3 is presented with the mark "1", indicating that the decision for the trimming process is in an enabled state.

[0087] In the foregoing embodiment, if the switching module 55 determines that the mechanical brake is not actuated during the current sampling and the current trimming mark is set to the first content, it means that the driver did not actuate the mechanical brake during the previous cycle detection and also did not actuate the mechanical brake during the current cycle (i.e., during the current detection), indicating that the driver still has no deceleration requirement. If the switching module 55 determines that the mechanical brake is not actuated during the current sampling, but the current trimming mark is set to the second content, it means that the driver actuated the mechanical brake during the previous cycle detection, but has released the mechanical brake during the current cycle (i.e., the actuation state 65 of the mechanical brake has changed), indicating that the driver is satisfied with the current speed and may even need to accelerate (so the mechanical brake is released). By the actuation state of the mechanical brake and the setting of the trimming mark, the speed command generation unit of the present invention can determine whether the driver intends to maintain the current speed or accelerate.

[0088] After considering all the data of the electric vehicle, including the calculated value of the previous cycle (i.e., the previous calculated value 64), the actuation state of the mechanical brake during the current cycle, the actuation state 65 of the mechanical brake during the previous cycle (i.e., the trimming mark), the current motor speed 66 of the motor, and the brake mode selection signal and other information, the switching module 55 can decide how to adjust the final output value 63, and then output the adjusted output value 63 to the motor to drive and control the operation of the motor.

[0089] As Figure 3 shown, the speed command generation unit of the present invention may further include a waiting module 57, and the waiting module 57 is mainly a software module connected to the calculation module 52.

[0090] Specifically, the electric vehicle can continuously detect the torque and torque current of the motor through an internal sensor (not shown in the figure), and determine whether the torque is saturated and whether the torque current is saturated, that is, determine whether the output of the driver has reached the upper limit. If the output of the driver reaches the upper limit (i.e., the torque saturation or torque current saturation state), it means that even if the driver continuously operates the throttle to accelerate, the motor of the electric vehicle can no longer generate additional power. At this time, the speed command generation unit of the present invention can lock the speed command (mainly the set value 61 of the locked speed command) through the waiting module 57 to achieve the effect of waiting for the speed command, for example, temporarily ignoring the throttle operation signal until the torque or torque current saturation state is released.

[0091] In one embodiment, when the torque and torque current of the motor are not saturated, the waiting module 57 sets the waiting flag to a third content (for example, sets the waiting flag to "non - waiting" or parameter "0" for software interpretation), indicating that there is no need to wait for the speed command, and the speed command setting value 61 can be normally accepted. Moreover, when the torque or torque current of the motor is saturated, the waiting module 57 sets the waiting flag to a fourth content (for example, sets the waiting flag to "waiting" or parameter "1"), indicating that the speed command needs to wait, and the speed command setting value 61 is not accepted temporarily before the content of the waiting flag is changed.

[0092] It is worth mentioning that in the previous embodiment, the calculation module 52 mainly provides the corresponding calculated value 62 according to the setting value 61 of the speed command when the mechanical brake is not actuated in this sampling, the trimming flag is set to the first content (that is, the mechanical brake was not actuated during the previous sampling), and the waiting flag is the third content (that is, neither the torque nor the torque current of the motor is saturated), without trimming the speed command and without waiting.

[0093] In addition, the calculation module 52 can also determine whether the setting value 61 is less than the calculated value 62 (that is, determine whether the driver has released the accelerator and intends to decelerate, but the mechanical brake has not been actuated yet) when the mechanical brake is not actuated in this sampling, the trimming flag is set to the first content, and the waiting flag is the fourth content (that is, the torque or torque current of the motor is saturated). In this embodiment, the calculation module 52 can pre - provide the corresponding calculated value 62 according to the current motor speed 66 of the motor when the setting value 61 is less than the calculated value 62 (equivalent to the signal path where the trimming flag is set to "1" in Figure 3 to make the driving stable and reduce jerks. And when the setting value 61 is greater than or equal to the calculated value 62, the calculation module 52 ignores the current calculated value 62 (that is, determines that the torque or torque current is saturated and the driver intends to accelerate, and makes the speed command wait), and directly uses the calculated value of the previous cycle (that is, the previous calculated value 64) as the calculated value 62 of this cycle (equivalent to the signal path where the trimming flag is set to "0" in Figure 3 .

[0094] As described above, after determining the calculated value 62, the driver then uses the calculated value 62 provided by the calculation module 52 as the basis through the switching module 55 to generate the output value 63 of the speed command.

[0095] In the present invention, the waiting module 57 is mainly used to solve the problem of torque or torque current saturation of the motor. The trimming module 56 is mainly used to solve the problem that when the driver releases the accelerator pedal to decelerate or releases the mechanical brake to accelerate during this sampling, the current speed command does not match the actual motor speed. The switching module 55 is mainly used to distinguish the influence on the speed command when the motor recovery brake assist function is turned on / off when the driver uses the mechanical brake.

[0096] Through the design of the above modules, the speed command control unit of the present invention can switch or trim the output value 63 of the speed command when the driver uses the mechanical brake and the brake recovery assist function, so that the speed command is consistent with the actual motor speed 66, and solve the problem of temporarily losing the braking force. In addition, when the driver steps on the accelerator pedal to accelerate or releases the accelerator pedal to decelerate, the speed command control unit of the present invention can also make the speed command wait, so that the speed command is consistent with the actual motor speed 66, and solve the problem that the driver may temporarily lose control of the electric vehicle. When the driver makes the electric vehicle carry heavy loads or climb slopes, the speed command control unit of the present invention can also quickly process the speed command by waiting / trimming the speed command to solve the problem that the driver will temporarily lose control of the electric vehicle.

[0097] Please also refer to Figure 3 and Figure 4 , where Figure 4 is a flowchart of the speed command generation method according to the first specific embodiment of the present invention. The present invention further discloses a speed command generation method for an electric vehicle (hereinafter simply referred to as the generation method in the specification). The generation method can be implemented by a speed command generation unit as shown in Figure 3 , and is mainly applied to the driver of the electric vehicle to control the motor of the electric vehicle.

[0098] It is worth mentioning that Figure 4 mainly discloses the operation logic of a set of program codes. The present invention regards the time required for the speed command generation unit to execute the operation logic shown in Figure 4 once between the start and end nodes as a cycle. And during the operation of the electric vehicle, the speed command generation unit will continuously execute the operation logic shown in Figure 4 in a loop for detection.

[0099] Such as Figure 4As shown, during the operation of the electric vehicle in the present invention, the driver (equipped with the speed command generation unit) continuously detects the actuation state 65 of the mechanical brake (step S10), and determines whether the driver actuates the mechanical brake in this cycle of detection based on the actuation state 65. When the driver determines that the mechanical brake is actuated in this cycle, it further determines whether the motor recovery brake assist function of the electric vehicle is activated (step S12), and correspondingly sets a switching flag.

[0100] In one embodiment, the driver can set the switching flag to the fifth content (for example, set to "non-recovering" or parameter "0" for software interpretation) or the sixth content (for example, set to "recovering" or parameter "1"). When the switching flag is set to the fifth content, it indicates that the motor recovery brake assist function is not actuated, and when the switching flag is set to the sixth content, it indicates that the motor recovery brake assist function is actuated. It is worth mentioning that after the driver determines that the mechanical brake is actuated and the switching flag has been set, it can control the electric vehicle to execute the corresponding braking method based on the content of the switching flag (that is, use / do not use the motor recovery brake assist function).

[0101] The above is only one specific embodiment of the present invention, but it is not limited thereto.

[0102] In the same detection cycle, when the driver determines that the motor recovery brake assist is not turned on (that is, the switching flag is set to the fifth content), it takes the current motor speed 66 of the electric vehicle motor as the basis to generate the output value 63 of the speed command (step S14). When the driver determines that the motor recovery brake assist is activated (that is, the switching flag is set to the sixth content), it takes the zero speed command as the basis to generate the output value 63 of the speed command (step S16). After step S14 or step S16, the driver can (through the switching module 55) determine the final output value 63, and output the output value 63 to the motor to perform drive control on the motor (step S18).

[0103] It is worth mentioning that in step S16, the driver mainly takes the zero speed command as the output value 63 of the speed command. Therefore, the torque command generated by the driver based on this output value 63 may be too large, resulting in too strong braking of the electric vehicle, too high instantaneous battery recharge power, and the problem that the battery cannot bear it. To solve the above problems, it is necessary to suppress the torque command calculated by the driver.

[0104] Please also refer to Figure 5 , the schematic diagram of the upper limit of the torque command in the first specific embodiment of the present invention. In Figure 5In an embodiment, the driver of the electric vehicle further has a controller 71 and a torque limit form 72, where the torque limit form 72 records the torque upper limit of the motor of the electric vehicle at different speeds. Specifically, the torque upper limit refers to the maximum torque that the motor can bear without causing damage to the motor, which is set during the original factory production of the motor.

[0105] In an embodiment, the controller 71 can be, for example, a Proportional-Integral-Derivative (PID) controller, or a PID controller without using the derivative function (i.e., a PI controller), which is not limited. In this embodiment, the controller 71 calculates the torque command 67 of the motor based on the output value 63 of the foregoing speed command, the current motor speed 66, and the torque upper limit of the motor, and controls the motor to rotate forward or backward through the torque command 67. Among them, the torque command 67 does not exceed the torque upper limit recorded in the torque limit form 72. For example, when the motor rotates in reverse, it will enter the power generation mode, and excessive torque may cause excessive current to flow back to the battery and damage the battery.

[0106] Specifically, the controller 71 mainly takes the difference between the output value 63 of the speed command and the current motor speed 66 as the output to calculate the torque command 67 for controlling the motor. The method for the controller 71 to calculate the torque command 67 is a common technical means in the technical field and will not be elaborated here.

[0107] In the present invention, the controller 71 queries the torque limit form 72 based on the current motor speed 66 of the electric vehicle motor to obtain the corresponding torque upper limit. In an embodiment, the electric vehicle can further be provided with an accelerator sensor (not shown in the figure), such as a brake switch or a light interrupter, for detecting the depression depth of the accelerator unit. However, the above is only one implementation example of the present invention and is not limited thereto.

[0108] Next, the controller 71 compares the calculated torque command 67 with the obtained torque upper limit to determine whether the torque command 67 exceeds the torque upper limit of the motor. If the torque command 67 does not exceed the torque upper limit, the controller 71 can directly output the torque command 67 to the motor. If the torque command 67 exceeds the torque upper limit, the controller 71 updates the torque command 67 with the torque upper limit, and then outputs the updated torque command 67 to the motor to drive and control the motor.

[0109] Through the above technical means, it is possible to effectively avoid the problem that when the motor recovery brake assist function is activated, the battery is damaged due to excessive torque causing too strong braking and the battery being unable to withstand the excessive current flowing back.

[0110] Back to Figure 4, if the driver of the electric vehicle determines in step S10 that the mechanical brake has not been actuated during the current cycle detection, it can further determine whether the mechanical brake was actuated during the previous sampling (i.e., the previous cycle detection) (step S20), and set a corresponding trimming flag. As described above, the driver mainly sets the trimming flag to the first content (for example, set to "disabled" or parameter "0") when determining that the mechanical brake was not actuated during the previous cycle, and sets the trimming flag to the second content (for example, set to "enabled" or parameter "1") when determining that the mechanical brake was actuated during the previous cycle.

[0111] In this embodiment, if the mechanical brake was not actuated during the previous cycle (i.e., the trimming flag is the first content), the driver will use the calculated value 62 of the speed command output by the calculation module 52 as a basis to generate the output value 63 of the speed command (step S22). Conversely, if the mechanical brake was actuated during the previous cycle (i.e., the trimming flag is the second content), the driver trims the speed command. At this time, the driver uses the current motor speed 66 of the motor as a basis to generate the output value 63 of the speed command (step S24).

[0112] Specifically, when executing Figure 4 step S22, it means that the mechanical brake was not actuated during the previous cycle and the current cycle, that is, the actuation state of the mechanical brake has not changed for at least a period of time. Therefore, the driver can directly use the calculated value 62 output by the calculation module 52 as a basis to generate the output value 63, without having to process and trim the speed command to accelerate the operation. And when executing Figure 4 step S24, it means that the mechanical brake was actuated during the previous cycle, but the driver has released the mechanical brake during the current cycle, that is, the actuation state of the mechanical brake has changed, and the driver may want to maintain a constant speed or accelerate. Therefore, the driver trims the output value 63 of the speed command to the motor speed 66, thereby avoiding the discomfort caused by the inconsistency between the speed command 61 and the actual motor speed 66.

[0113] After step S22 or step S24, the driver can (through the switching module 55) determine the final output value 63, and output the output value 63 to the motor to perform drive control on the motor (step S18).

[0114] Specifically, as Figure 3 shown, the speed command generation unit used by the driver may further include a waiting module 57. In the case where the mechanical brake was not actuated during the previous cycle and the current cycle, the driver can further consider the waiting flag set by the waiting module 57 to determine how to process the speed command.

[0115] Please also refer toFigure 6 , which is a flowchart of the speed command generation method according to the second specific embodiment of the present invention. In this embodiment, the driver first determines that the mechanical brake has not been actuated in both the detection of the previous cycle and the detection of the current cycle (step S30). At this time, the driver uses the throttle operation signal sent by the throttle module 51 as the set value 61 of the speed command (step S32). Then, the driver determines whether the torque or torque current of the motor is saturated (step S34).

[0116] If it is determined in step S34 that both the torque and the torque current are not saturated, the driver can set the waiting flag to a third content (for example, set to "not wait" or the parameter "0" for easy software interpretation) to represent that the speed command does not need to wait in the current cycle. At this time, the driver provides a corresponding calculated value 52 of the speed command based on the set value 61 of the speed command (step S36), and uses the calculated value 52 as the basis to generate the output value 63 of the speed command to drive and control the motor (step S38). In other words, in steps S36 and S38, the driver does not process or trim the speed command, but directly calculates the output value 63 of the speed command according to the general procedure based on the throttle operation signal and the previous calculated value 64 (that is, the calculated value 62 of the speed command in the previous cycle), that is, bypasses the speed command trimming process.

[0117] If it is determined in step S34 that the torque of the motor is saturated or the torque current of the motor is saturated, the driver can set the waiting flag to a fourth content (for example, set to "wait" or the parameter "1") to represent that the speed command needs to wait in the current cycle. At this time, the driver further determines whether the set value 61 is less than the calculated value 62 provided by the calculation module 52 (step S40), that is, determines whether the driver releases the throttle and has the intention of decelerating.

[0118] If it is determined in step S40 that the set value 61 is greater than or equal to the calculated value 62, it means that the driver does not have the intention of decelerating and may even be accelerating. At this time, the driver can ignore the calculated value 62 of this time (step S42), and directly use the calculated value of the previous cycle (that is, the previous calculated value 64) as the basis to generate the output value 63 of the speed command of the current cycle to drive and control the motor (step S44), that is, bypasses the speed command trimming process.

[0119] On the other hand, if it is determined in step S40 that the set value 61 is less than the calculated value 62, it means that the driver releases the accelerator pedal with the intention of decelerating. At this time, the driver changes to provide the calculated value 62 according to the current motor speed 66 of the motor (that is, the calculation module 52 replaces the previous calculated value 64 with the motor speed 66 and inputs it into the calculation module 52), and uses this calculated value 62 as the basis to generate the output value 63 of the speed command for this cycle to drive and control the motor (step S46).

[0120] As described above, the speed command generation unit and generation method of the present invention are based on information such as the actuation states of the mechanical brakes detected this time and last time on the electric vehicle, the braking method selected by the driver, and the conditions of the upper limit of the motor torque and torque current, etc., to switch or trim the speed command. Thereby, it can solve the problem that when the output torque of the electric vehicle is saturated, or when the driver steps on the mechanical brake, the controllability of the movement behavior of the electric vehicle may be temporarily lost.

[0121] Please refer to Figure 7A and Figure 7B 、 Figure 8A and Figure 8B and Figure 9A and Figure 9B and Figure 7A and Figure 7B respectively show the schematic diagrams of speed command optimization for the first to third specific embodiments of the present invention. Among them, Figure 8A and Figure 8B disclose the situation when the driver actuates the mechanical brake, Figure 9A and Figure 9B disclose the situations when the driver steps on the accelerator pedal hard to accelerate and releases the accelerator pedal to decelerate,

[0122] such as Figure 7A and Figure 7B shown, in the related art (as shown in Figure 7A ), if the horizontal axis represents time, the motor speed 81 on the vertical axis will lag slightly behind the speed command 82 when the electric vehicle starts to accelerate (the left half of the attached drawing), and will first rapidly decrease due to the braking torque provided by the mechanical brake (the box part in the right half of the attached drawing). However, the speed command 82 is not modified due to the actuation of the mechanical brake, thus causing jerks. At this time, since the speed command 82 is greater than the actual motor speed 81, the controller will still calculate a positive torque command. After the motor receives the torque command, it will generate an accelerating torque that resists the mechanical brake, resulting in a decrease in braking efficiency and even causing the electric vehicle to have no braking force for a short time. In this case, the driver will feel an abnormal riding experience and unexpected movement behavior.

[0123] In the present invention (as shown in Figure 7BAs shown (in the right - hand side boxed part of the attached drawing), when the mechanical brake is actuated, in addition to the motor speed 91 decreasing, the speed command 92 is also immediately modified (for example Figure 4 as shown in step S14 of Figure 7A wherein its value is specified as the current motor speed). At this time, since the speed command 92 is consistent with the motor speed 91, the controller does not calculate the torque command, so the motor does not generate an accelerating torque that resists the mechanical brake. From Figure 7B it can be seen that if the technical solution of the present invention is adopted, the driver will not have an abnormal riding feeling when actuating the mechanical brake, nor will they feel unexpected motion behavior.

[0124] Next, as shown in Figure 8A and Figure 8B in the related art (as shown in Figure 8A ), when the driver presses the accelerator pedal hard to accelerate, causing the motor to exhibit torque saturation, as shown by the curve of torque 83 in the attached drawing, after continuously pressing the accelerator pedal, the torque 83 curve tends to be horizontal and cannot increase further. At this time, the motor speed 81 cannot effectively track the speed command 82. Because in the related art, the driver does not properly process the speed command 82. Even if the driver releases the accelerator pedal at this time, the electric vehicle will not immediately decelerate, but will wait until the speed command 82 continuously decreases and is lower than the motor speed 81 before starting to decelerate. In this case, the driver will briefly lose control of the electric vehicle.

[0125] In the present invention (as shown in Figure 8B ), when the torque 93 is saturated (the boxed part in the attached drawing), the driver makes the speed command 92 wait (for example Figure 6 steps S42 and S44 shown in Figure 6 ignoring the current speed command and based on the previous calculated value). At this time, since the acceleration of the speed command 92 is less than the preset value due to the trigger command waiting, the speed command 92 and the motor speed 91 can be kept consistent. For example

[0126] as shown in step S46 of Figure 8B using the current motor speed as the calculated value.

[0127] Next, as shown in Figure 9A and Figure 9B in the related art (as shown in Figure 9A ), when the driver operates an electric vehicle for heavy load or climbing, causing the motor to exhibit torque saturation, the motor speed 81 cannot effectively track the speed command 82. At this time, as shown in the right half of the attached drawing, since the driver does not properly process the speed command 82 in the related art, after the driver releases the accelerator (the speed command 82 curve starts to decline smoothly), the electric vehicle does not immediately decelerate (the motor speed 81 curve does not immediately follow and decline), but only starts to decelerate after the speed command 82 continues to decline and is lower than the motor speed 81. In this case, the driver will briefly lose control of the electric vehicle.

[0128] In the present invention (as shown in Figure 9B ), the driver makes the speed command 92 wait when torque saturation occurs, and when the driver releases the accelerator, by trimming the speed command 92, the electric vehicle can immediately respond to the throttle operation signal and perform a corresponding deceleration action (for example, step S46 shown in Figure 6 ), based on the current motor speed as the calculated value). As can be seen from Figure 9B , by adopting the technical solution of the present invention, the driver will not briefly lose control of the electric vehicle due to torque saturation. As shown in the right half of the attached drawing, the speed command is calculated based on the current motor speed at the moment when the driver releases the accelerator, without waiting for a period of time.

[0129] The above are only the preferred specific examples of the present invention, and thus do not limit the patent scope of the present invention. Therefore, all equivalent changes made by using the content of the present invention are similarly included in the scope of the present invention, and are hereby stated.

Claims

1. A speed command generation unit for an electric vehicle, which is applied to a driver of an electric vehicle. The driver is used to drive a motor of the electric vehicle, and the speed command generation unit comprises: An accelerator module that calculates a set value of a speed command according to an accelerator operation signal generated by an external operation; A calculation module that generates a calculated value of the speed command based on the set value; A mechanical brake sensing module that continuously detects an actuation state of a mechanical brake of the electric vehicle; A brake mode selection module; A trimming module connected to the mechanical brake sensing module and the calculation module. The trimming module sets a trimming flag to disabled when the mechanical brake was not actuated during the previous sampling, and sets the trimming flag to enabled when the mechanical brake was actuated during the previous sampling; and A switching module connected to the calculation module, the mechanical brake sensing module, the brake mode selection module, and the trimming module. When the mechanical brake sensing module samples that the mechanical brake is not actuated and the trimming flag is disabled during this sampling, the switching module uses the calculated value as a basis to generate an output value of the speed command to drive and control the motor. When the mechanical brake sensing module samples that the mechanical brake is not actuated and the trimming flag is enabled during this sampling, the switching module uses the current motor speed of the motor as a basis to generate the output value of the speed command to drive and control the motor. And when the mechanical brake sensing module samples that the mechanical brake is actuated during this sampling, the switching module switches the brake mode based on a brake mode selection signal provided by the brake mode selection module, and uses the brake mode selection signal as a basis to generate the output value of the speed command to drive and control the motor.

2. The speed command generation unit for an electric vehicle according to claim 1, wherein the brake mode selection module provides the brake mode selection signal to indicate whether a motor regeneration brake assist function is activated. And when the mechanical brake is actuated and the brake mode selection signal indicates that the motor regeneration brake assist function is not activated during this sampling, the switching module uses the motor speed as a basis to generate the output value. And when the mechanical brake is actuated and the brake mode selection signal indicates that the motor regeneration brake assist function is activated during this sampling, the switching module uses a zero speed command as a basis to generate the output value.

3. The speed command generation unit for an electric vehicle according to claim 2, further comprises: A torque limit table that records a torque upper limit of the motor at different speeds; and A controller that calculates a torque command of the motor based on the output value, the motor speed, and the torque upper limit, wherein the torque command does not exceed the torque upper limit.

4. The speed command generation unit for an electric vehicle according to claim 1, further comprises a waiting module connected to the calculation module. The plurality of waiting modules set a waiting flag to not wait when a torque of the motor and a torque current are both not saturated. When the mechanical brake is not actuated, the trimming flag is disabled, and the plurality of waiting flags are not waiting during this sampling, the calculation module provides the calculated value according to the set value, and the switching module uses the calculated value as a basis to generate the output value.

5. The speed command generation unit for an electric vehicle as claimed in claim 4, wherein when the torque or the torque current is saturated, the calculation module sets a plurality of the to-be-marked as waiting, and when the mechanical brake is not actuated in this sampling, the trimming flag is disabled, and a plurality of the to-be-marked are waiting, it determines whether the set value is less than the calculated value. When the set value is greater than or equal to the calculated value, it ignores the calculated value and uses the calculated value of the previous cycle as the calculated value of this cycle, and when the set value is less than the calculated value, it provides the calculated value according to the motor speed.

6. A speed command generation method for an electric vehicle, which is applied to a driver of an electric vehicle. The driver is used to drive a motor of the electric vehicle. The driver includes a speed command generation unit. The speed command generation unit calculates a set value of a speed command according to an accelerator signal and generates a calculated value of the speed command based on the set value. The speed command generation method comprises: a) Continuously detecting an actuation state of a mechanical brake of the electric vehicle; b) Setting a trimming flag according to the actuation state at the previous sampling, wherein when the trimming flag is disabled, it means that the mechanical brake was not actuated at the previous sampling, and when the trimming flag is enabled, it means that the mechanical brake was actuated at the previous sampling; c) When it is determined in step a) that the mechanical brake is not actuated in this sampling, and when the trimming flag is set to be disabled in step b), using the calculated value of the speed command in this sampling as a basis to generate an output value of the speed command; d) When it is determined in step a) that the mechanical brake is not actuated in this sampling, and when the trimming flag is set to be enabled in step b), using a current motor speed of the motor as a basis to generate the output value of the speed command; e) After step c) or step d), outputting the output value to the motor to drive and control the motor; and f) When it is determined in step a) that the mechanical brake is actuated in this sampling, switching the braking mode based on a braking mode selection signal, and using the braking mode selection signal as a basis to generate the output value of the speed command to drive and control the motor.

7. The speed command generation method for an electric vehicle as claimed in claim 6, wherein step f) comprises: f1) Setting a switching flag according to the braking mode selection signal, wherein when the switching flag is no recovery, it means that a motor recovery braking assistance function is not started, and when the switching flag is with recovery, it means that the motor recovery braking assistance function is started; f2) When the switching flag is no recovery, using the motor speed as a basis to generate the output value of the speed command; f3) When the switching flag is with recovery, using a zero speed command as a basis to generate the output value of the speed command; and f4) After step f2) or step f3), outputting the output value to the motor to drive and control the motor.

8. The speed command generation method for an electric vehicle as claimed in claim 6, wherein after step e) or step f), it further comprises: g) Calculate a torque command for the motor based on the output value, the motor speed, and a torque upper limit, where the torque command does not exceed the torque upper limit.

9. The method for generating a speed command in an electric vehicle according to claim 6, wherein the step c) comprises: c1) Determine whether a torque of the motor is saturated; c2) Determine whether a torque current of the motor is saturated; and c3) When both the torque and the torque current are not saturated, provide the calculated value according to the set value, and use the calculated value as a basis to generate the output value.

10. The method for generating a speed command in an electric vehicle according to claim 9, wherein after the step c3), it further comprises: c4) When the torque or the torque current is saturated, determine whether the set value is less than the calculated value; c5) When the set value is greater than or equal to the calculated value, ignore the calculated value, and use the calculated value of the previous cycle as a basis to generate the output value; and c6) When the set value is less than the calculated value, provide the calculated value according to the motor speed, and use the calculated value as a basis to generate the output value.

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