Energy recovery control method and system for landing of shear fork arm

Abstract

The invention discloses an energy recovery control method and system for landing of a shear fork arm. The energy recovery control method for landing of the shear fork arm comprises the steps that a PCU operates the shear fork arm to descend, and a controller controls a lifting electromagnetic valve to be powered on, controls a descending electromagnetic valve to be powered on and starts a driver; the descending electromagnetic valve is electrified to enable the variable-amplitude oil cylinder to retract, and the shear fork arm falls down; when the lifting electromagnetic valve is electrified, hydraulic oil in a large cavity of the variable-amplitude oil cylinder reaches a CSE port of a main valve through an oil cylinder valve block and then reaches an outlet of the gear pump through the lifting electromagnetic valve, and the gear pump rotates reversely; the gear pump rotates reversely to drive the two-way pump motor to rotate reversely; the controller controls the reverse rotation speed of the gear pump by detecting the current value of reverse power generation of the two-way pump motor; the inverted bi-directional pump motor charges the battery through the driver. And the endurance of the shear forklift truck is improved while the energy consumption is reduced.

Description

Technical Field

[0001] The invention relates to an energy recovery control method and a system for the landing of a scissor lift arm, belonging to the technical field of scissor lift trucks. Background Art

[0002] As competition in the aerial work platform industry continues to intensify at home and abroad, improving the performance of scissor-type aerial work platforms while maintaining low prices is an important direction of current design.

[0003] With the increase in usage, extremely high requirements are placed on the battery life of electric scissor lifts. Current electric scissor lifts do not have energy recovery function. Summary of the invention

[0004] The present invention provides an energy recovery control method and system for scissor arm landing, which solves the problems disclosed in the background technology.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: Energy recovery control method for scissor arm landing: When the energy recovery function is enabled, the controller obtains the instruction from the PCU to operate the scissor arm to lower, and controls the lifting solenoid valve to be energized, the lowering solenoid valve to be energized, and the driver to be turned on; The descending solenoid valve is energized to retract the luffing cylinder, the scissor arm falls, the lifting solenoid valve is energized, and the hydraulic oil in the large chamber of the luffing cylinder passes through the cylinder valve block to the CSE port of the main valve, and then passes through the lifting solenoid valve to the gear pump outlet. The falling potential energy drives the gear pump to reverse; The gear pump reverses to drive the bidirectional pump motor to reverse; The controller detects the current value of the bidirectional pump motor in reverse power generation, and controls the reverse speed of the gear pump according to the current value; The reversing bidirectional pump motor charges the battery via the drive.

[0006] Further, the energy function of lowering the scissor arms cannot be performed when the energy recovery function is disabled.

[0007] Furthermore, when the storage battery is a lead-acid battery, energy recovery is allowed at any ambient temperature and any SOC.

[0008] Furthermore, when the storage battery is a lithium battery, energy recovery is only allowed under the conditions of a temperature of [0°C, 10°C), an SOC of [0%, 90%) and a temperature of [10°C, 60°C).

[0009] Furthermore, it also includes a controller that detects the current value of the reverse power generation of the bidirectional pump motor. When the current value exceeds the set limit value, the lifting solenoid valve is energized, and the falling speed is controlled by controlling the reverse speed of the bidirectional pump motor to reduce the current value to within the limit value.

[0010] Furthermore, the current value of the bidirectional pump motor reverse power generation ; Among them, k is the motor constant; Ф is the magnetic flux; N is the number of coil turns; R is the motor internal resistance; and n is the motor speed.

[0011] Furthermore, when energy recovery is prohibited, if the reversal of the bidirectional pump motor is detected during descent, the controller alarms but does not prohibit the action; When energy recovery is enabled, if it is detected that the bidirectional pump motor is not reversing during descent, the controller will alarm and prohibit the falling action and lifting action.

[0012] Furthermore, when a partial fault alarm related to the bidirectional pump motor, driver, and battery occurs, the energy recovery function is turned off.

[0013] Furthermore, the lowering solenoid valve is opened for a preset time later than the lifting solenoid valve.

[0014] The second invention of the present invention provides an energy recovery control system for scissor arm lowering, comprising a PCU, a lifting solenoid valve, a lowering solenoid valve, a driver, a gear pump, a bidirectional pump motor and a battery; The PCU operates the scissor arm to descend, and the controller controls the lifting solenoid valve to be energized, the descending solenoid valve to be energized, and the driver to be turned on; The descending solenoid valve is energized to retract the luffing cylinder, the scissor arm falls, the lifting solenoid valve is energized, and the hydraulic oil in the large chamber of the luffing cylinder passes through the cylinder valve block to the CSE port of the main valve, and then passes through the lifting solenoid valve to the gear pump outlet. The falling potential energy drives the gear pump to reverse; The gear pump reverses to drive the bidirectional pump motor to reverse; The controller detects the current value of the bidirectional pump motor in reverse power generation, and controls the reverse speed of the gear pump according to the current value; The reversing bidirectional pump motor charges the battery via the drive.

[0015] The beneficial effects achieved by the present invention are: The present invention keeps the lifting solenoid valve energized when the scissor arm falls, and the large-cavity hydraulic oil of the variable-length oil cylinder reaches the CSE port of the main valve through the oil cylinder valve block, and then reaches the outlet of the gear pump through the lifting solenoid valve. The falling potential energy drives the gear pump to reverse, and the reverse rotation of the gear pump drives the motor to reverse and generate electricity, and then the battery is charged through the driver, thereby saving energy consumption and improving the endurance of the scissor lift truck. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is a schematic diagram of the control flow of the present invention; Figure 2 It is a schematic diagram of the gear pump control knob in the present invention. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0018] Example 1: Figure 1 As shown, this embodiment provides an energy recovery control method for scissor arm landing, comprising the following steps: The PCU operates the scissor arm to descend, and the controller controls the lifting solenoid valve to be energized, the descending solenoid valve to be energized, and the driver to be turned on; The descending solenoid valve is energized to retract the luffing cylinder, the scissor arm falls, the lifting solenoid valve is energized, and the large-chamber hydraulic oil of the luffing cylinder passes through the cylinder valve block to the CSE port of the main valve, and then passes through the lifting solenoid valve to the gear pump outlet. The falling potential energy drives the gear pump to reverse; The gear pump reverses to drive the bidirectional pump motor to reverse; The controller controls the reverse speed of the gear pump by detecting the current value of the reverse power generation of the bidirectional pump motor; The reversing bidirectional pump motor charges the battery via the drive.

[0019] The gear pump adopts a bidirectional gear pump that can rotate forward and reverse. The gear pump reversing function recovers the potential energy of the scissor arm falling and transmits it to the motor. The electrical system detects the voltage level and current direction, calculates and judges the received data, and transmits it to the battery to recover the falling potential energy for reuse. At the same time, the damping in the descending solenoid valve is cancelled, and the potential energy of the oil cylinder falling will not be consumed by the damping, and it can be better transmitted to the motor through the reverse rotation of the gear pump. The electrical system detects this part of energy and charges the battery, and then provides it to the vehicle load as energy again.

[0020] Energy recovery control logic 1. The controller panel configuration options include energy recovery function options: enable / disable.

[0021] 2. When the energy recovery function is set to "Disable", the machine will enter the normal lifting mode and the energy recovery function will not be enabled.

[0022] 3. When the energy recovery function is selected as "Enabled", the vehicle will enter the energy recovery mode based on the battery used; Depending on the type of battery, set the following conditions to allow energy recovery: Lead-acid battery: Lead-acid batteries have strong tolerance and temperature adaptability, so lead-acid batteries allow energy recovery at any ambient temperature and any SOC; Lithium battery: Lithium battery has strict requirements on charging current. Different ambient temperatures and SOC conditions allow different charging currents or prohibit charging. Therefore, it is necessary to turn off the energy recovery function when charging is prohibited or the allowed charging current is relatively small. The parameters need to be set according to the different performance of lithium batteries. For reference, please refer to the following:

[0023] Energy recovery function activated: Lifting: The control mode of scissor arm lifting is the same as the normal mode. When lifting, the lifting solenoid valve is energized, the motor drives the gear pump, and the CSE port of the main valve discharges oil to provide hydraulic oil to the large chamber of the lifting cylinder to achieve the lifting action; Lowering: When the scissor arm drops, the lifting solenoid valve is energized, and the hydraulic oil in the large chamber of the luffing cylinder reaches the CSE port of the main valve through the cylinder valve block, and then reaches the gear pump outlet through the lifting solenoid valve. The falling potential energy drives the gear pump to reverse, and the gear pump reverses to drive the motor to reverse and generate electricity. At this time, the bus voltage of the controller increases. When the bus voltage is higher than the battery voltage, the battery is charged to achieve the purpose of energy recovery.

[0024] The controller detects the current value generated by the reverse power generation of the motor. When the current value exceeds the set limit value, the falling speed can be controlled by controlling the reverse speed of the motor to reduce the current value to within the limit value.

[0025] Current value of bidirectional pump motor reverse power generation ; Among them, k is the motor constant; Ф is the magnetic flux; N is the number of coil turns; R is the motor internal resistance; and n is the motor speed.

[0026] This embodiment sets the following security protection measures: When energy recovery is prohibited, if the motor reverses when the scissor arm is lowered, the controller will alarm but will not prohibit the action; When energy recovery is enabled, if the motor is detected not to reverse when the scissors are lowered, the controller will alarm and prohibit the scissors from falling or lifting. When a partial fault alarm related to the bidirectional pump motor, driver, or battery occurs, the energy recovery function is turned off to prevent the fault from worsening, such as: motor temperature is too high, controller temperature is overheated, lithium battery failure uploaded by the BMS, etc.

[0027] Since there is a slight setback at the beginning of the falling action, it is necessary to open the descending solenoid valve later than the lifting solenoid valve. The late opening time is obtained based on actual measurements.

[0028] like Figure 2As shown, in order to simplify the operation, the gear pump knob is turned left to act as a pump, and the gear pump rotates forward to perform the scissor arm lifting action; when the gear pump is turned right to act as a motor, the gear pump reverses to achieve the energy recovery function.

[0029] Embodiment 2: This embodiment provides an energy recovery control system for scissor arm lowering, including a PCU, a lifting solenoid valve, a lowering solenoid valve, a driver, a gear pump, a bidirectional pump motor and a battery; The PCU operates the scissor arm to descend, and the controller controls the lifting solenoid valve to be energized, the descending solenoid valve to be energized, and the driver to be turned on; The descending solenoid valve is energized to retract the luffing cylinder, and the scissor arm falls. The hydraulic oil in the large chamber of the luffing cylinder passes through the cylinder valve block to the CSE port of the main valve, and then passes through the lifting solenoid valve to the gear pump outlet. The falling potential energy drives the gear pump to reverse. The gear pump reverses to drive the bidirectional pump motor to reverse; The controller controls the reverse speed of the gear pump by detecting the current value of the reverse power generation of the bidirectional pump motor; The reversing bidirectional pump motor charges the battery via the drive.

[0030] Embodiment 3: This embodiment provides a scissor lift truck, which is equipped with the energy recovery control system for the descent of the scissor lift arm described in Embodiment 2; the power unit of the scissor lift truck adopts a permanent magnet synchronous pump motor, which has the advantages of high efficiency, small size, high power density, low temperature rise, energy saving and environmental protection compared with AC asynchronous motors; an energy recovery liquid-electric control system is developed to control the safety logic and recovery efficiency during the energy recovery process, and recycle and reuse the energy of the scissor lift arm's own weight when it descends, so as to further improve the endurance of the whole machine.

[0031] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention and are not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. The energy recovery control method for the scissor arm landing is characterized by: When the energy recovery function is enabled, the controller obtains the instruction from the PCU to operate the scissor arm to lower, and controls the lifting solenoid valve to be energized, the lowering solenoid valve to be energized, and the driver to be turned on; The descending solenoid valve is energized to retract the luffing cylinder, the scissor arm falls, the lifting solenoid valve is energized, and the hydraulic oil in the large chamber of the luffing cylinder passes through the cylinder valve block to the CSE port of the main valve, and then passes through the lifting solenoid valve to the gear pump outlet. The falling potential energy drives the gear pump to reverse; The gear pump reverses to drive the bidirectional pump motor to reverse; The controller detects the current value of the bidirectional pump motor in reverse power generation, and controls the reverse speed of the gear pump according to the current value; The reversing bidirectional pump motor charges the battery via the drive.

2. The energy recovery control method for scissor arm landing according to claim 1, characterized in that: The energy function of lowering the scissor arms cannot be performed when the energy recovery function is disabled.

3. The energy recovery control method for scissor arm landing according to claim 1, characterized in that: When the storage battery is a lead-acid battery, energy recovery is allowed at any ambient temperature and any SOC.

4. The energy recovery control method for scissor arm landing according to claim 1, characterized in that: When the battery is a lithium battery, energy recovery is only allowed under the conditions of a temperature of [0°C, 10°C), a SOC of [0%, 90%) and a temperature of [10°C, 60°C).

5. The energy recovery control method for scissor arm landing according to claim 1, characterized in that: When the current value exceeds the set limit value, the falling speed is controlled by controlling the reverse rotation speed of the bidirectional pump motor to reduce the current value to within the limit value.

6. The energy recovery control method for scissor arm landing according to claim 1, characterized in that: Current value of bidirectional pump motor reverse power generation ; Among them, k is the motor constant; Ф is the magnetic flux; N is the number of coil turns; R is the motor internal resistance; and n is the motor speed.

7. The energy recovery control method for scissor arm landing according to claim 1, characterized in that: When energy recovery is prohibited, if the bidirectional pump motor is detected to be reversed during descent, the controller will alarm but will not prohibit the action; When energy recovery is enabled, if it is detected that the bidirectional pump motor is not reversing during descent, the controller will alarm and prohibit the falling action and lifting action.

8. The energy recovery control method for scissor arm landing according to claim 1, characterized in that: When a partial fault alarm related to the bidirectional pump motor, driver, and battery occurs, the energy recovery function is turned off.

9. The energy recovery control method for scissor arm landing according to claim 1, characterized in that: The lowering solenoid valve is opened for a preset time later than the lifting solenoid valve.

10. The energy recovery control system for the scissor arm landing is characterized by: Includes PCU, lifting solenoid valve, lowering solenoid valve, driver, gear pump, bidirectional pump motor and battery; When the energy recovery function is enabled, the controller obtains the instruction from the PCU to operate the scissor arm to lower, and controls the lifting solenoid valve to be energized, the lowering solenoid valve to be energized, and the driver to be turned on; The descending solenoid valve is energized to retract the luffing cylinder, the scissor arm falls, the lifting solenoid valve is energized, and the hydraulic oil in the large chamber of the luffing cylinder passes through the cylinder valve block to the CSE port of the main valve, and then passes through the lifting solenoid valve to the gear pump outlet. The falling potential energy drives the gear pump to reverse; The gear pump reverses to drive the bidirectional pump motor to reverse; The controller detects the current value of the bidirectional pump motor in reverse power generation, and controls the reverse speed of the gear pump according to the current value; The reversing bidirectional pump motor charges the battery via the drive.

Images