A pure electric cement mixer truck mounted power taking control circuit and method

Abstract

The present invention discloses a power-taking control circuit and method for a pure electric cement mixer. It includes a key ignition switch for outputting an ON signal; a vehicle controller for outputting a closing instruction for the main negative contactor of the power battery and a closing instruction for the upper power circuit contactor; a power battery system for controlling the closing of the main negative contactor of the power battery to output high voltage electricity to the vehicle power distribution unit; a vehicle power distribution unit for controlling the closing of the upper power circuit contactor to complete the upper high-voltage power distribution; an upper motor controller for outputting an upper power-taking request CAN message signal to the vehicle controller after being enabled, and outputting an upper power-taking request hard-wire signal to the vehicle controller, the power battery system and the vehicle power distribution unit, for controlling the upper motor to work after the upper high-voltage power distribution is completed. The upper motor controller power-taking request of the cement mixer of the present invention adopts CAN line and hard-wire redundant control to ensure the reliability of upper power taking.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile control, and in particular relates to a power taking control circuit and method for a pure electric cement mixer truck. Background Art

[0002] At present, the cement tanks on pure electric cement mixer trucks are mostly powered by electricity, that is, the motor controller on the upper part obtains high voltage electricity from the vehicle upper or chassis power battery and high-voltage power distribution device, and then drives the upper cement tank to rotate. At present, there are two control schemes for the motor controller on the upper part to obtain electricity from the vehicle chassis power battery and high-voltage power distribution device:

[0003] Solution 1: The upper motor controller sends a power-on request to the high-voltage vehicle control unit (VCU) via a CAN message. The VCU sends a power-on instruction to the battery management system (BMS) and the high-voltage power distribution unit (PDU) to power the relevant contactors based on the power-on request from the upper motor controller, thereby realizing power supply to the upper motor controller.

[0004] Solution 2: The upper motor controller transmits the power-drawing request through the hard-wired connection between the I / O port of the VCU and the PDU. It is agreed that when there is a request for upper motor power, the relevant I / O ports of the VCU and PDU are set to a high level, and the power battery and the relevant contactors of the PDU are controlled to be attracted through a certain timing to realize the power supply of the upper motor controller.

[0005] The existing technical solutions all have the disadvantages of unreliable power supply and unloading:

[0006] Solution 1: When the upper-mounted high voltage is powered on, if the CAN line is disconnected or the CAN communication fails, the VCU cannot receive the power-on request from the upper-mounted motor controller in time, and cannot coordinate the BMS and PDU to respond to the high-voltage power-on demand of the upper-mounted motor controller, causing the cement tank of the cement mixer to stop and the cement inside to solidify; when the upper-mounted motor controller is working, if the CAN line is disconnected or the CAN communication fails, the VCU mistakenly determines that the upper-mounted high-voltage power-on request is invalid, and enters the upper-mounted high-voltage power-off process. If the driver makes a mistake and does not turn off the upper-mounted equipment, the vehicle is turned off first and a load disconnect instruction is issued to the PDU for the upper-mounted power-on circuit contactor, causing the upper-mounted power-on circuit contactor inside the PDU to be disconnected with load, resulting in adhesion.

[0007] Solution 2: When the upper body high voltage is powered on, the upper body motor controller's high voltage power request hard-wire signal is lost due to problems such as I / O pin cold soldering, wire harness breakage, and poor connector contact. The chassis's VCU and PDU modules cannot respond to the upper body motor controller's high voltage power demand in time, causing the cement tank of the cement mixer truck to stop and the cement inside to solidify. When the upper body motor controller is working, if the upper body power hard-wire signal is disconnected, the VCU mistakenly determines that the upper body high voltage power request is invalid and enters the upper body high voltage power-off process. If the driver makes a mistake and does not turn off the upper body equipment, he will first turn off the vehicle and send a load disconnect command to the PDU for the upper body power-on circuit contactor, causing the upper body power-on circuit contactor inside the PDU to be disconnected with load, resulting in adhesion. Summary of the invention

[0008] The purpose of the present invention is to solve the deficiencies of the above-mentioned background technology and to provide a power supply control circuit and method for a pure electric cement mixer truck to improve the reliability of power supply.

[0009] The technical solution adopted by the present invention is: a power taking control circuit installed on a pure electric cement mixer, comprising

[0010] The key ignition switch is used to close when high voltage power is required and output an ON signal;

[0011] The vehicle controller is used to send a power battery main negative contactor closing instruction and a body power request CAN message signal to the power battery system when receiving an ON signal and a body power request CAN message signal, and send a body power circuit contactor closing instruction and a body power request CAN message signal to the vehicle power distribution unit; and is used to send a power battery main negative contactor closing instruction to the power battery system and a body power circuit contactor closing instruction to the vehicle power distribution unit when receiving an ON signal and a body power request hard-line signal;

[0012] The power battery system is used to control the power battery main negative contactor to close and output high voltage electricity to the vehicle power distribution unit when receiving the power battery main negative contactor closing instruction, and the upper installation power taking request CAN message signal and / or the upper installation power taking request hard line signal;

[0013] The vehicle power distribution unit is used to control the closing of the body power circuit contactor to complete the body high-voltage power distribution when receiving the body power circuit contactor closing instruction, the body power request CAN message signal and / or the body power request hard-line signal;

[0014] The upper motor controller is used to output the upper power request CAN message signal to the vehicle controller after being enabled, and output the upper power request hard-line signal to the vehicle controller, the power battery system and the vehicle power distribution unit, so as to control the upper motor to work after the upper high-voltage power distribution is completed;

[0015] The upper body start switch is used to close when the upper body high voltage power is required to enable the upper body motor controller.

[0016] Furthermore, when the vehicle controller and the vehicle power distribution unit have not received the CAN message signal of the upper installation power request or the hard-wire signal of the upper installation power request, the vehicle controller reports a CAN line timeout failure or a upper installation power request hard-wire signal loss failure, or the vehicle power distribution unit reports a CAN line timeout failure or a upper installation power request hard-wire signal loss failure.

[0017] Furthermore, when the vehicle controller, the power battery system and the vehicle power distribution unit simultaneously receive a CAN message signal of a top-mounted power-drawing request and a hard-wire signal of a top-mounted power-drawing request, it is preferred to respond to the CAN message signal of a top-mounted power-drawing request.

[0018] Furthermore, when the vehicle power distribution unit controls the body power circuit contactor to close, it first controls the body power circuit pre-charging contactor to close, and at the same time detects the pressure difference between the front and rear ends of the body power circuit main contactor. When the front and rear end pressure difference is less than the preset value and lasts for a certain period of time, the body power circuit main contactor is controlled to close.

[0019] A method for controlling power supply of a pure electric cement mixer, including power supply and power supply process:

[0020] Turn the vehicle key ignition switch to the ON position to wake up the vehicle controller, the battery management system in the power battery system and the vehicle power distribution unit; press the body start switch to enable the body motor controller;

[0021] After being enabled, the upper motor controller outputs the upper power-taking request CAN message signal to the vehicle controller, and outputs the upper power-taking request hard-wire signal to the vehicle controller, the power battery system and the vehicle power distribution unit;

[0022] The vehicle controller sends a power battery main negative contactor closing command and a bodywork power-taking request CAN message signal to the battery management system, and sends a bodywork power circuit contactor closing command and a bodywork power-taking request CAN message signal to the vehicle power distribution unit;

[0023] When the battery management system receives the closing command of the main negative contactor of the power battery, as well as the CAN message signal of the upper equipment power-taking request and / or the hard-line signal of the upper equipment power-taking request, it controls the main negative contactor of the power battery to close and output high voltage electricity to the vehicle power distribution unit;

[0024] When the vehicle power distribution unit receives the closing instruction of the body power circuit contactor, as well as the body power request CAN message signal and / or the body power request hard wire signal, it controls the body power circuit contactor to close to complete the body high-voltage power distribution.

[0025] Furthermore, when the vehicle controller and the vehicle power distribution unit have not received the CAN message signal of the upper installation power request or the hard-wire signal of the upper installation power request, the vehicle controller reports a CAN line timeout failure or a upper installation power request hard-wire signal loss failure, or the vehicle power distribution unit reports a CAN line timeout failure or a upper installation power request hard-wire signal loss failure.

[0026] Furthermore, when the vehicle controller, the power battery system and the vehicle power distribution unit simultaneously receive a CAN message signal of a top-mounted power-drawing request and a hard-wire signal of a top-mounted power-drawing request, it is preferred to respond to the CAN message signal of a top-mounted power-drawing request.

[0027] Furthermore, when the vehicle power distribution unit controls the body power circuit contactor to close, it first controls the body power circuit pre-charging contactor to close, and at the same time detects the pressure difference between the front and rear ends of the body power circuit main contactor. When the front and rear end pressure difference is less than the preset value and lasts for a certain period of time, the body power circuit main contactor is controlled to close.

[0028] Furthermore, it also includes the process of loading, taking power and unloading power:

[0029] Disconnect the upper load power switch, unload the upper load motor controller, and reset the upper load power request CAN message signal and the upper load power request hard line signal;

[0030] When the vehicle controller detects that the power-on request is invalid based on the CAN message signal of the power-on request and the hard-wire signal of the power-on request, it sends a CAN communication timeout fault and a power-on circuit contactor disconnection instruction to the vehicle power distribution unit.

[0031] When the vehicle power distribution unit receives the disconnection instruction of the body power circuit contactor and detects that the body power supply request is invalid, it controls the body power circuit contactor to disconnect and feeds back the body power circuit contactor status and rear-end voltage to the vehicle controller;

[0032] After the vehicle controller confirms that the body power circuit contactor is disconnected, it sends a body power request CAN message signal and a power battery main negative contactor disconnection instruction to the battery management system, and feeds back the body power circuit contactor status and rear-end voltage to the body motor controller;

[0033] When the bodywork motor controller confirms that the bodywork power circuit contactor is disconnected and the voltage at the rear end of the bodywork power circuit main contactor is less than the set voltage, active discharge is performed;

[0034] When the battery management system receives the power battery main negative contactor disconnection instruction and detects that the upper load power request is invalid, it controls the power battery main negative contactor to disconnect.

[0035] Furthermore, the detection of the upper power-drawing request is invalid when the following conditions are met at the same time:

[0036] 1) CAN communication timeout failure; 2) The CAN message signal of the upper power request is invalid; 3) The hard-wire signal of the upper power request is low level.

[0037] The beneficial effects of the present invention are:

[0038] The power request of the upper motor controller of the cement mixer truck of the present invention adopts CAN line and hard line redundant control to avoid the erroneous judgment of entering the power-off process of the upper power installation due to the loss of the upper high-voltage power request signal along the way, thereby ensuring the reliability of the upper power installation; and the CAN line signal and the hard-line request signal are fault-checked to identify the possible risk of power request signal loss, and promptly remind the driver to check related line faults to avoid the situation where the upper high-voltage power request CAN signal and the hard-line signal are lost at the same time, thereby further improving the reliability of the upper power installation; at the same time, the present invention refers to the two-way redundant power request signal to formulate a delayed power-off strategy for the PDU upper power installation circuit contactor to avoid the risk of adhesion caused by the contactor short-circuiting under load. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The figure is a schematic diagram of the principle of the high-voltage power taking control circuit installed in the present invention.

[0040] Figure 2 This is a flow chart of the high voltage power supply and controller of the present invention.

[0041] Figure 3 This is a flow chart of installing high voltage power supply and powering up the VCU according to the present invention.

[0042] Figure 4 This is a flow chart of installing high voltage power supply and powering BMS in the present invention.

[0043] Figure 5 This is a flow chart of installing a high-voltage power supply PDU according to the present invention.

[0044] Figure 6 This is a flow chart of the controller for installing high voltage power taking and lowering power in the present invention.

[0045] Figure 7 This is a flow chart of the present invention for installing high voltage power supply and powering VCU.

[0046] Figure 8 This is a flow chart of the present invention for installing high voltage power supply and powering BMS.

[0047] Fig. 9 This is a flow chart of installing a high-voltage power-taking and power-down PDU according to the present invention. DETAILED DESCRIPTION

[0048] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0049] like Figure 1 As shown, the present invention provides a power taking control circuit for a pure electric cement mixer, comprising

[0050] The key ignition switch 101 is used to close when high voltage power is required and output an ON signal;

[0051] The vehicle controller (VCU) 102 is used to send a power battery main negative contactor closing instruction and a body power request CAN message signal to the power battery system when receiving an ON signal and a body power request CAN message signal, and send a body power circuit contactor closing instruction and a body power request CAN message signal to the vehicle power distribution unit; it is used to send a power battery main negative contactor closing instruction to the power battery system and send a body power circuit contactor closing instruction to the vehicle power distribution unit when receiving an ON signal and a body power request hard-line signal;

[0052] The power battery system 103 is used to control the power battery main negative contactor 105 to close and output high voltage electricity to the vehicle power distribution unit when the battery management system (BMS) 104 receives a power battery main negative contactor closing instruction, as well as a CAN message signal of a power-taking request from an upper body and / or a hard-wire signal of a power-taking request from an upper body;

[0053] The vehicle power distribution unit (PDU) 106 is used to control the body power circuit contactor 107 to close and complete the body high voltage power distribution when receiving the body power circuit contactor closing instruction, and the body power request CAN message signal and / or the body power request hard line signal;

[0054] The upper motor controller 108 is used to output the upper power supply request CAN message signal to the vehicle controller after being enabled, and output the upper power supply request hard-line signal to the vehicle controller, the power battery system and the vehicle power distribution unit, so as to control the upper motor 109 to work after the upper high-voltage power distribution is completed;

[0055] The upper body start switch 110 is used to close when the upper body needs to take high voltage power to enable the upper body motor controller.

[0056] In the above scheme, when the vehicle controller does not receive the upper-mounted power-drawing request CAN message signal or the upper-mounted power-drawing request hard-wire signal, it reports a CAN line timeout fault or an upper-mounted power-drawing request hard-wire signal loss fault. Or when the vehicle power distribution unit does not receive the upper-mounted power-drawing request CAN message signal or the upper-mounted power-drawing request hard-wire signal, it reports a CAN line timeout fault or an upper-mounted power-drawing request hard-wire signal loss fault. The vehicle controller or vehicle power distribution unit of the present invention can identify the possible risk of power-drawing request signal loss by performing fault verification on the CAN line signal and the hard-wire request signal in real time, and promptly remind the driver to check related line faults to avoid the situation where the upper-mounted high-voltage power-drawing request CAN signal and the hard-wire signal are lost at the same time; and when the response request signal is not received at the same time, only one unit reports a fault, avoiding repeated fault reporting and saving computing resources.

[0057] In the above scheme, when the vehicle controller, the power battery system and the vehicle power distribution unit simultaneously receive the upper installation power request CAN message signal and the upper installation power request hard wire signal, it is preferred to respond to the upper installation power request CAN message signal.

[0058] In the above scheme, when controlling the closing of the main negative contactor of the power battery and the closing of the upper power supply circuit contactor, the corresponding status is fed back to the vehicle controller after a certain delay, which can avoid the risk of adhesion caused by the contactor short circuit under load.

[0059] Based on the above-mentioned pure electric cement mixer truck top-mounted power supply control system, the present invention also provides a pure electric cement mixer truck top-mounted power supply control method, including a top-mounted power supply power-on process and a top-mounted power supply power-off process.

[0060] The process of powering on the upper part is as follows:

[0061] Turn the vehicle key ignition switch to the ON position to wake up the vehicle controller, the battery management system in the power battery system and the vehicle power distribution unit; press the body start switch to enable the body motor controller;

[0062] After the upper motor controller is enabled, it outputs the upper power-taking request CAN message signal to the vehicle controller through the CAN bus, and outputs the upper power-taking request hard-wire signal to the vehicle controller, the power battery system and the vehicle power distribution unit through the physical hard wire;

[0063] After receiving the CAN message signal of the upper body power supply request, the vehicle controller sends the power battery main negative contactor closing instruction and the upper body power supply request CAN message signal to the battery management system, and sends the upper body power supply circuit contactor closing instruction and the upper body power supply request CAN message signal to the vehicle power distribution unit;

[0064] When the battery management system receives the closing command of the main negative contactor of the power battery, as well as the CAN message signal of the upper equipment power-taking request and / or the hard-line signal of the upper equipment power-taking request, it controls the main negative contactor of the power battery to close and output high voltage electricity to the vehicle power distribution unit;

[0065] When the vehicle power distribution unit receives the closing instruction of the body power circuit contactor, as well as the body power request CAN message signal and / or the body power request hard wire signal, it controls the body power circuit contactor to close to complete the body high-voltage power distribution.

[0066] The process of taking power from the upper part and removing power from the upper part is as follows:

[0067] Disconnect the upper load power switch, unload the upper load motor controller, and reset the upper load power request CAN message signal and the upper load power request hard line signal;

[0068] When the vehicle controller detects that the power-on request is invalid based on the CAN message signal of the power-on request and the hard-wire signal of the power-on request, it sends a CAN communication timeout fault and a power-on circuit contactor disconnection instruction to the vehicle power distribution unit.

[0069] When the vehicle power distribution unit receives the disconnection instruction of the body power circuit contactor and detects that the body power supply request is invalid, it controls the body power circuit contactor to disconnect and feeds back the body power circuit contactor status and rear-end voltage to the vehicle controller;

[0070] After the vehicle controller confirms that the body power circuit contactor is disconnected, it sends a body power request CAN message signal and a power battery main negative contactor disconnection instruction to the battery management system, and feeds back the body power circuit contactor status and rear-end voltage to the body motor controller;

[0071] When the bodywork motor controller confirms that the bodywork power circuit contactor is disconnected and the voltage at the rear end of the bodywork power circuit main contactor is less than the set voltage, active discharge is performed;

[0072] When the battery management system receives the power battery main negative contactor disconnection instruction and detects that the upper load power request is invalid, it controls the power battery main negative contactor to disconnect.

[0073] The power request of the upper motor controller of the cement mixer truck of the present invention adopts CAN line and hard line redundant control, which avoids the erroneous judgment of entering the upper power-on power-off process due to the loss of the upper high-voltage power request signal along the way, thereby ensuring the reliability of upper power-on power-on.

[0074] When the upper-mounted power is powered on, the present invention reduces the failure rate of "the upper-mounted high-voltage power request signal is lost" by verifying the upper-mounted high-voltage power request CAN message signal and the hard-wire signal: when the upper-mounted high-voltage power request CAN message signal and the hard-wire signal are valid at the same time, the VCU and the PDU give priority to responding to the CAN message signal; when a CAN communication failure or timeout occurs and the upper-mounted high-voltage power request hard-wire signal is valid, the VCU and the PDU distribute power to the upper-mounted motor controller according to the hard-wire signal, and the VCU or the PDU reports a CAN line timeout failure; when the CAN bus has no abnormality or timeout, and the upper-mounted high-voltage power request CAN signal is valid and the hard-wire signal is invalid, the VCU and the PDU module distribute power to the upper-mounted motor controller according to the CAN signal, and the PDU module reports a failure of the upper-mounted power request hard-wire signal being lost, so as to remind the driver to go to the service station to check the relevant line failure, so as to avoid the situation where the upper-mounted high-voltage power request CAN signal and the hard-wire signal are lost at the same time.

[0075] The VCU and PDU of the present invention can detect the CAN signal and hard-wire signal of the upper-mounted high-voltage power request to avoid the risk of adhesion caused by the disconnection of the contactor under load, which may lead to the erroneous judgment of entering the upper-mounted power supply power-off process due to the loss of the upper-mounted high-voltage power request signal along the way: when the PDU upper-mounted power supply circuit has a high-voltage output and the CAN signal or hard-wire signal of the upper-mounted high-voltage power request is lost, the PDU module can judge whether to maintain the upper-mounted high-voltage power supply or enter the upper-mounted high-voltage power supply power-off process according to the hard-wire signal or CAN signal of the upper-mounted high-voltage power request.

[0076] Figure 2-5 The present invention is based on Figure 1 The control system of a pure electric cement mixer truck is equipped with a high-voltage power distribution power-on flow chart.

[0077] Figure 2 The control flow chart of the upper body controller when the upper body is powered on is shown. First, the upper body controller low-voltage self-test is performed at 201. After the self-test is completed, 202 is executed, that is, whether the upper body start switch is closed. If it is pressed, 203 is executed in sequence to set the upper body power request hard-wire pin DO_upper level, 204 sends the upper body power request CAN signal Enable_upper to the VCU, and 205 receives the PDU status message (upper body power main contactor status and rear-end voltage) forwarded by the VCU. Then the upper body controller enters 206 to judge whether the upper body power is completed, that is, the upper body circuit main contactor is closed Relay_upper_sat==1 and the contactor rear-end voltage Uo_Relay rises to more than 90% of the rated voltage Uo_bat of the power battery. If the condition 206 is true, the upper body controller executes 207 and starts normal operation, otherwise it continues to wait for the upper body power circuit to be powered on.

[0078] Figure 3The control flow chart of the VCU when the upper body is powered on is shown. The VCU first executes 208 to receive and parse the upper body power request CAN signal in the message sent by the upper body controller and 209 to detect the upper body power request hard-line signal, that is, the DI_upper pin level. Then enter 210 to determine whether the upper body power request is valid, that is, the upper body power request CAN signal is valid Enable_upper==1 or the hard-line signal is valid and the DI_upper pin is high. If it is valid, execute 211 to send the power battery negative contactor closing instruction to the BMS and wait for the negative contactor to act. When it is determined in 212 that the power battery negative contactor is closed, execute 213 to set the upper body power enable bit in the PDU control message, and finally execute 214 to receive the PDU status message (upper body power main contactor status and rear-end voltage) and 215 to forward the PDU status message (upper body power main contactor status and rear-end voltage).

[0079] Figure 4 This is the control flow chart of the BMS when the upper part is powered on. The BMS first executes 216 to receive and parse the BMS control message sent by the VCU, and 217 to detect the upper part power request hard-line signal, that is, the DI_upper pin level. Then the BMS enters 218 to determine whether the upper part power request is valid, that is, the upper part power request CAN signal is valid Enable_neg == 1 or the hard-line signal is valid DI_upper pin is high level. If it is valid, execute 219 to close the negative contactor of the power battery, and execute 220 after a delay of 100ms, and feedback the negative contactor status of the power battery Relay_neg_sat is closed.

[0080] Figure 5This is the control flow chart of the PDU when the upper load is powered on. The PDU first executes 221 to receive and parse the PDU control message sent by the VCU, and 222 to detect the upper load power request hard-wire signal, that is, the DI_upper pin level. Then, the PDU enters 223 to determine whether the upper load power request is valid. When the CAN signal and the hard-wire signal are valid at the same time, that is, Enable_upper==1&&DI_upper pin is high, the upper load power circuit contactor closing process 228 and the upper load power circuit status feedback process 229 are sequentially executed. If the judgment condition 223 is false, enter 224 to continue to determine whether the upper load power request is valid. When the CAN signal is valid and the hard-wire signal is invalid, that is, Enable_upper==1&&DI_upper pin is low, execute 225 to report the "upper load power request hard-wire signal loss" fault through the DM1 message, and then execute 228 and 229. If the judgment condition in 224 is false, then proceed to 226 to continue to judge whether the upper-mounted power-on request is valid. When the CAN signal is invalid and the hard-line signal is valid, that is, Enable_upper==0&&DI_upper pin is high level, then execute 227 to report the "CAN communication timeout or interruption" fault through DM1 message, and delay 200ms to wait for the power battery negative contactor to close, and then execute 228 and 229. If 227 is also false, it is determined that there is no upper-mounted high-voltage power-on request.

[0081] Figure 6-9 The present invention is based on Figure 1 The control system of a pure electric cement mixer truck is equipped with a high-voltage power distribution flow chart.

[0082] Figure 6 The control flow chart of the upper-mounted controller when the upper-mounted power is taken off and powered off is shown. First, the upper-mounted controller performs a self-test during operation at 301. After the self-test is completed, 302 is executed to determine whether the upper-mounted start switch is disconnected. If it is disconnected, 303 is executed to unload the upper-mounted controller and the IGBT is turned off. Then, 304 is executed to judge and wait for the upper-mounted unloading. When the judgment condition at 304 is true, 305 is sequentially executed to reset the upper-mounted power-taking request hard-wire pin DO_upper level, 306 resets the upper-mounted power-taking request CAN signal Enable_upper sent to the VCU, and 307 receives the PDU status message (upper-mounted power-taking main contactor status and rear-end voltage) forwarded by the VCU. Finally, enter 308 to determine whether the upper-mounted power-taking circuit contactor of the PDU is disconnected, that is, Relay_upper_sat==1&&Uo_Relay<Uo_bat*80%. If it is true, 309 is executed for the upper-mounted controller to discharge the high voltage actively. If it is false, go to 307 and wait for the upper-mounted power-taking circuit contactor of the PDU to be disconnected before executing 309.

[0083] Figure 7The control flow chart of VCU when the upper part is powered on and off is shown. VCU first executes 310 to receive and parse the upper part power request CAN signal Enable_upper in the message sent by the upper part controller, and 311 detects the upper part power request hard-line signal, that is, the DI_upper pin level. Then enter 312 to judge whether the upper part power request is invalid, that is, the upper part power request CAN signal is valid Enable_upper==0 and the hard-line signal is valid DI_upper pin is low level. If it is invalid, execute 313 to send the upper part power circuit contactor disconnection instruction to PDU, 314 to receive PDU status message (upper part power main contactor status and rear-end voltage), and 315 to forward PDU status message (upper part power main contactor status and rear-end voltage). Then enter 316 to judge whether the upper part power circuit contactor is disconnected. If the contactor is disconnected, the power battery main negative contactor disconnection instruction is sent to BMS, otherwise go to 314 to continue waiting for the disconnection of the upper part contactor.

[0084] Figure 8 This is the control flow chart of the BMS when the upper load is powered on or off. The BMS first executes 318 to receive and parse the BMS control message sent by the VCU, and 319 to detect the upper load power request hard-line signal, that is, the DI_upper pin level. Then, the BMS enters 320 to determine whether the upper load power request is invalid, that is, the upper load power request CAN signal is valid Enable_neg==0 and the hard-line signal is valid DI_upper pin is low level. If it is invalid, execute 321 to disconnect the negative contactor of the power battery, and execute 322 after a delay of 100ms, and feedback the negative contactor status of the power battery Relay_neg_sat is disconnected.

[0085] Fig. 9 This is the control flow chart of the PDU when the upper load is powered on and off. The PDU first executes 323 to receive and parse the PDU control message sent by the VCU, and 324 to detect the upper load power request hard-wire signal, that is, the DI_upper pin level. Then, the PDU enters 325 to determine whether the PDU currently has a CAN communication timeout fault. If there is no CAN communication timeout fault, 326 is executed to determine whether the current CAN communication timeout fault is invalid. If it is invalid, 329 is executed to disconnect the main contactor of the upper load power circuit and delay 100ms, and then 330 is executed to feedback the current upper load power circuit contactor state Relay_upper_sat and the rear end voltage Uo_Relay of the main contactor. If 325 determines that there is a CAN communication timeout fault, 327 is entered to determine whether the current upper load power request hard-wire signal is invalid. If it is invalid, 328 is executed to delay the upper load for 5s to wait for the upper load controller to unload, and then 329 and 330 are executed. If the judgment condition at 327 is invalid, go to 323 to continue waiting and determine whether the upper load high voltage power supply and power off conditions are met.

[0086] The above symbols are explained as follows:

[0087] KeyON——Key ON block signal;

[0088] DO_Upper——upper power hard line request output signal;

[0089] DI_Upper——upper power hard line request input signal;

[0090] Enable_upper——CAN signal for upper power request;

[0091] Enable_neg——Power battery negative contactor enable;

[0092] Relay_upper_sat——upper power main contactor status;

[0093] Relay_neg_sat——power battery main negative contactor status;

[0094] Uo_Relay——the voltage at the rear end of the main contactor of the upper power supply circuit;

[0095] Uo_bat——power battery output voltage.

[0096] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field.

Claims

1. A power-taking control circuit for a pure electric cement mixer, characterized in that: It includes a key ignition switch, which is used to close when high voltage power is required and output an ON signal; The vehicle controller is used to send a power battery main negative contactor closing instruction and a body power request CAN message signal to the power battery system when receiving an ON signal and a body power request CAN message signal, and send a body power circuit contactor closing instruction and a body power request CAN message signal to the vehicle power distribution unit; and is used to send a power battery main negative contactor closing instruction to the power battery system and a body power circuit contactor closing instruction to the vehicle power distribution unit when receiving an ON signal and a body power request hard-line signal; The power battery system is used to control the power battery main negative contactor to close and output high voltage electricity to the vehicle power distribution unit when receiving the power battery main negative contactor closing instruction, and the upper installation power taking request CAN message signal and / or the upper installation power taking request hard line signal; The vehicle power distribution unit is used to control the closing of the body power circuit contactor to complete the body high-voltage power distribution when receiving the body power circuit contactor closing instruction, the body power request CAN message signal and / or the body power request hard-line signal; The upper motor controller is used to output the upper power request CAN message signal to the vehicle controller after being enabled, and output the upper power request hard-line signal to the vehicle controller, the power battery system and the vehicle power distribution unit, so as to control the upper motor to work after the upper high-voltage power distribution is completed; The upper body start switch is used to close when the upper body high voltage power is required to enable the upper body motor controller.

2. The power taking control circuit for a pure electric cement mixer according to claim 1 is characterized in that: When the vehicle controller and the vehicle power distribution unit do not receive the CAN message signal of the upper installation power request or the hard-wire signal of the upper installation power request, the vehicle controller reports a CAN line timeout failure or a upper installation power request hard-wire signal loss failure, or the vehicle power distribution unit reports a CAN line timeout failure or a upper installation power request hard-wire signal loss failure.

3. The power taking control circuit for a pure electric cement mixer according to claim 1 is characterized in that: When the vehicle controller, the power battery system and the vehicle power distribution unit simultaneously receive the upper installation power request CAN message signal and the upper installation power request hard-line signal, it is preferred to respond to the upper installation power request CAN message signal.

4. The power taking control circuit for a pure electric cement mixer according to claim 1 is characterized in that: When the vehicle power distribution unit controls the body power circuit contactor to close, it first controls the body power circuit pre-charging contactor to close, and at the same time detects the pressure difference between the front and rear ends of the body power circuit main contactor. When the pressure difference between the front and rear ends is less than the preset value and lasts for a certain period of time, the body power circuit main contactor is controlled to close.

5. A method for controlling power supply of a pure electric cement mixer, characterized in that: Including the process of powering on: Turn the vehicle key ignition switch to the ON position to wake up the vehicle controller, the battery management system in the power battery system and the vehicle power distribution unit; press the body start switch to enable the body motor controller; After being enabled, the upper motor controller outputs the upper power-taking request CAN message signal to the vehicle controller, and outputs the upper power-taking request hard-wire signal to the vehicle controller, the power battery system and the vehicle power distribution unit; The vehicle controller sends a power battery main negative contactor closing command and a bodywork power-taking request CAN message signal to the battery management system, and sends a bodywork power circuit contactor closing command and a bodywork power-taking request CAN message signal to the vehicle power distribution unit; When the battery management system receives the closing command of the main negative contactor of the power battery, as well as the CAN message signal of the upper equipment power-taking request and / or the hard-line signal of the upper equipment power-taking request, it controls the main negative contactor of the power battery to close and output high voltage electricity to the vehicle power distribution unit; When the vehicle power distribution unit receives the closing instruction of the body power circuit contactor, as well as the body power request CAN message signal and / or the body power request hard wire signal, it controls the body power circuit contactor to close to complete the body high-voltage power distribution.

6. The method for controlling power supply of a pure electric cement mixer according to claim 5, characterized in that: When the vehicle controller and the vehicle power distribution unit do not receive the CAN message signal of the upper installation power request or the hard-wire signal of the upper installation power request, the vehicle controller reports a CAN line timeout failure or a upper installation power request hard-wire signal loss failure, or the vehicle power distribution unit reports a CAN line timeout failure or a upper installation power request hard-wire signal loss failure.

7. The method for controlling power supply of a pure electric cement mixer according to claim 5, characterized in that: When the vehicle controller, the power battery system and the vehicle power distribution unit simultaneously receive the upper installation power request CAN message signal and the upper installation power request hard-line signal, it is preferred to respond to the upper installation power request CAN message signal.

8. The method for controlling power supply of a pure electric cement mixer according to claim 5, characterized in that: When the vehicle power distribution unit controls the body power circuit contactor to close, it first controls the body power circuit pre-charging contactor to close, and at the same time detects the pressure difference between the front and rear ends of the body power circuit main contactor. When the pressure difference between the front and rear ends is less than the preset value and lasts for a certain period of time, the body power circuit main contactor is controlled to close.

9. The method for controlling power supply of a pure electric cement mixer according to claim 5, characterized in that: It also includes the process of loading, removing power and removing power: Disconnect the upper load power switch, unload the upper load motor controller, and reset the upper load power request CAN message signal and the upper load power request hard line signal; When the vehicle controller detects that the power-on request is invalid based on the CAN message signal of the power-on request and the hard-wire signal of the power-on request, it sends a CAN communication timeout fault and a power-on circuit contactor disconnection instruction to the vehicle power distribution unit. When the vehicle power distribution unit receives the disconnection instruction of the body power circuit contactor and detects that the body power supply request is invalid, it controls the body power circuit contactor to disconnect and feeds back the body power circuit contactor status and rear-end voltage to the vehicle controller; After the vehicle controller confirms that the body power circuit contactor is disconnected, it sends a body power request CAN message signal and a power battery main negative contactor disconnection instruction to the battery management system, and feeds back the body power circuit contactor status and rear-end voltage to the body motor controller; When the bodywork motor controller confirms that the bodywork power circuit contactor is disconnected and the voltage at the rear end of the bodywork power circuit main contactor is less than the set voltage, active discharge is performed; When the battery management system receives the power battery main negative contactor disconnection instruction and detects that the upper load power request is invalid, it controls the power battery main negative contactor to disconnect.

10. The method for controlling power supply of a pure electric cement mixer according to claim 9, characterized in that: The detection load power request is invalid when the following conditions are met at the same time: 1) CAN communication timeout failure; 2) The CAN message signal of the upper power request is invalid; 3) The hard-wire signal of the upper power request is low level.

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