Negative feedback closed-loop control method for constant-flow hydraulic pump

Abstract

The invention relates to a negative feedback closed-loop control method for a constant-flow hydraulic pump, which comprises the following steps of: transmitting power of an air blower to the hydraulic pump, monitoring the rotating speed of the hydraulic pump by a rotating speed sensor and transmitting an acquired signal to a PLC (Programmable Logic Controller), quickly analyzing and processing the signal by the PLC, and controlling the hydraulic pump according to a preset control strategy. A corresponding control instruction is generated and then sent to the servo driver, the servo driver accurately regulates and controls the servo electric cylinder to move according to the received instruction, the swing angle of the hydraulic pump is adjusted in real time through stretching and retracting of the servo electric cylinder, and after the swing angle is adjusted, the output flow of the hydraulic pump is also changed. And the change of the rotating speed of the hydraulic pump again can be captured by the rotating speed sensor and fed back to the system again for a new round of adjustment, and the cycle is repeated, so that a closed-loop real-time control process is formed. The torque of wind power is completely converted into hydraulic pressure, it is guaranteed that the output flow of the hydraulic pump is constant, and stable power generation of the hydraulic motor generator is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of wind power generation, and in particular to a negative feedback closed-loop control method for a constant flow hydraulic pump. Background Art

[0002] Marine power generation is mainly driven by diesel power to drive generators, thereby generating electricity for ship navigation and life. Diesel engines are noisy, affecting the crew's rest, and diesel is a non-renewable fossil energy with high energy loss. Therefore, offshore wind power generation is gradually replacing diesel power generation, but wind power is unstable, and the hydraulic energy transmitted by the hydraulic pump is also variable, which will affect the efficiency of wind power generation. Therefore, it is urgent to design a constant flow hydraulic pump negative feedback closed-loop control method to ensure that the output flow of the hydraulic pump is always stable within the specified range to achieve efficient wind power generation. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a constant flow hydraulic pump negative feedback closed-loop control method, which mainly solves the frequency and voltage of energy stable power generation in wind changes. There is no need to change the blade angle and lose wind energy. The wind torque is completely converted into hydraulic pressure, which greatly improves the wind energy conversion rate. The speed sensor and the servo electric cylinder are coordinated to monitor the speed of the hydraulic pump in real time. The flow rate output by the hydraulic pump forms an inverse proportional relationship with the speed of the fan, ensuring that the output flow of the hydraulic pump is constant and ensuring stable power generation of the hydraulic motor generator.

[0004] The object of the present invention is achieved in that: A negative feedback closed-loop control method for a constant flow hydraulic pump includes a hydraulic pump, which includes a pump housing, a main shaft, a variable swing, a return spring, a variable push rod, a plunger and a cylinder body. The main shaft is rotatably arranged in the pump housing, and a variable swing is arranged on the main shaft. The variable swing is connected to the plunger, and the plunger is slidably arranged in the cylinder body. The cylinder body is fixedly sleeved on the main shaft, and the variable swing is connected to the variable push rod. The servo electric cylinder is fixed outside the pump housing, and the movable end of the servo electric cylinder extends into the pump housing to connect the variable push rod. The shaft end of the main shaft extends out of the pump housing and is rigidly connected to the fan. A speed sensor is installed at the input end of the main shaft, and the servo electric cylinder is electrically connected to a servo controller. The servo controller and the speed sensor are both electrically connected to a PLC programming controller.

[0005] Preferably, the variable push rod is arranged on one side of the variable swing, and a return spring is arranged on the other side of the variable swing.

[0006] Preferably, the variable push rod and the return spring are symmetrically arranged on both sides of the main shaft, and the variable push rod and the return spring are distributed on the outside of the plunger.

[0007] Preferably, the movable end of the servo electric cylinder is extended to push the variable push rod on one side of the variable swing to move, the variable swing swings, and the return spring on the other side of the variable swing is compressed, so that the product of the displacement and the speed of the hydraulic pump is constant at the initial set value; The active end of the servo electric cylinder is shortened, pulling the variable push rod on one side of the variable swing to move, the variable swing swings, and the return spring on the other side of the variable swing resets, so that the product of the displacement and speed of the hydraulic pump is constant at the initial set value.

[0008] The beneficial effects of the present invention are: 1. High precision: With its advanced feedback adjustment mechanism, it can realize real-time and precise control of pump output under various working conditions, ensuring the high-precision requirements of system operation; it can achieve higher control accuracy, reaching 0.5~±1% high accuracy. The servo electric cylinder itself has high-precision position and speed control characteristics, and directly acts on the variable push rod to change the swing angle of the hydraulic pump, reducing the error transmission in the intermediate links, and can more accurately control the flow of the hydraulic pump; the execution time is shorter, which can be between 5 milliseconds and 20 milliseconds. The servo electric cylinder can quickly respond to the control signal and directly drive the variable push rod to move, reducing the delay links such as the intermediate hydraulic transmission, and has a faster dynamic response speed; 2. High stability: Through effective regulation of flow and pressure, the system can maintain a stable output state under different working conditions, greatly enhancing the reliability of system operation; 3. Strong adaptability: Regardless of the complex and ever-changing working environment or the diverse work tasks, the system can respond quickly and adjust flexibly to fully meet the special needs of different working conditions. It can be widely used in various technical fields such as fixed land wind power generation and wind power generation for sailing ships, vehicles, and mobile platforms; 4. High energy conversion rate: In the process of adjusting unit flow, hydraulic energy is cleverly used to optimize system pressure, effectively reduce unnecessary energy loss, significantly improve energy utilization efficiency, reduce wind energy consumption, and thus maximize wind energy conversion rate, providing strong support for sustainable energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a structural schematic diagram of a negative feedback closed-loop control method for a constant flow hydraulic pump of the present invention.

[0010] Figure 2 Schematic diagram of the internal structure of the hydraulic pump.

[0011] Figure 3 This is a schematic diagram of wind power generation using the present invention.

[0012] Among them: hydraulic pump 1; pump housing 1.1; main shaft 1.2; variable swing 1.3; return spring 1.4; variable push rod 1.5; plunger 1.6; cylinder body 1.7; servo electric cylinder 2; servo controller 3; PLC programming controller 4; speed sensor 5; fan 6; hydraulic motor 7; generator 8; inverter energy storage device 9. DETAILED DESCRIPTION

[0013] See also Figure 1-3 The present invention relates to a negative feedback closed-loop control method for a constant flow hydraulic pump, comprising a hydraulic pump 1, a servo electric cylinder 2, a servo controller 3, a PLC programming controller 4 and a speed sensor 5. The hydraulic pump 1 comprises a pump housing 1.1, a main shaft 1.2, a variable swing 1.3, a reset spring 1.4, a variable push rod 1.5, a plunger 1.6 and a cylinder body 1.7. The main shaft 1.2 is rotatably arranged in the pump housing 1.1 through a bearing, and a variable swing 1.3 is arranged on the main shaft 1.2. The variable swing 1.3 is connected to the plunger 1.6, and the plunger 1.6 is slidably arranged in the cylinder body 1.7. The cylinder body 1.7 is fixedly sleeved on the main shaft 1.2. The main shaft 1.2 rotates, driving the variable swing 1.3, the plunger 1.6 and the cylinder body 1.7 to rotate. The variable swing 1.3 is also connected with a variable push rod 1.5 and a return spring 1.4, which are symmetrically arranged on both sides of the main shaft 1.2, and the variable push rod 1.5 and the return spring 1.4 are distributed on the outside of the plunger 1.6. The servo electric cylinder 2 is fixed outside the pump housing 1.1 of the hydraulic pump 1, and the movable end of the servo electric cylinder 2 is connected with the variable push rod 1.5. The shaft end of the main shaft 1.2 extends out of the pump housing 1.1 and is rigidly connected to the air extraction fan 6. A speed sensor 5 is installed at the input end of the main shaft 1.2. The servo electric cylinder 2 is electrically connected to the servo controller 3, and the servo controller 3 and the speed sensor 5 are both electrically connected to the PLC programming controller 4.

[0014] Working principle: The power of the fan is transmitted to the hydraulic pump. The speed sensor is responsible for monitoring the speed of the hydraulic pump and transmitting the collected signal to the PLC programming controller. The PLC programming controller quickly analyzes and processes the signal, generates corresponding control instructions according to the preset control strategy, and then sends the instructions to the servo driver. The servo driver accurately controls the movement of the servo electric cylinder according to the received instructions, and adjusts the swing angle of the hydraulic pump in real time through the extension and retraction of the servo electric cylinder. After the swing angle is adjusted, the output flow of the hydraulic pump also changes accordingly. The speed of the hydraulic pump changes again and is captured by the speed sensor, and fed back to the system for a new round of adjustment. This cycle is repeated to form a closed-loop real-time control process, which enables the servo electric cylinder to continuously and dynamically adjust the swing angle of the hydraulic pump, thereby ensuring that the output flow of the hydraulic pump is always stable within the specified range.

[0015] Specifically: When the wind force increases, the spindle speed increases, the speed sensor sends a signal, the PLC programming controller generates data instructions, the servo controller processes the signal and amplifies the instruction, the active end of the servo electric cylinder moves, pushing the variable push rod on one side of the variable swing to swing, the variable swing swings, and the return spring on the other side of the variable swing is compressed, so that the product of the displacement of the hydraulic pump and the speed is constant at the initial set value; when the wind force becomes stronger (the speed increases) or weaker (the speed decreases), the above-mentioned variable displacement process is repeated.

[0016] In addition to the above embodiments, the present invention also includes other implementation modes. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the protection scope of the claims of the present invention.

Claims

1. A negative feedback closed-loop control method for a constant flow hydraulic pump, characterized in that: A constant flow hydraulic pump negative feedback closed-loop control system is adopted, the negative feedback closed-loop control system includes a hydraulic pump, a servo electric cylinder, a servo controller, a PLC programming controller and a speed sensor, the hydraulic pump includes a pump housing, a main shaft, a variable swing and a variable push rod, the main shaft drives the variable swing and the plunger to rotate, the variable swing is connected with the variable push rod, the servo electric cylinder is fixed outside the pump housing, the active end of the servo electric cylinder extends into the pump housing to connect the variable push rod, the shaft end of the main shaft extends out of the pump housing and is rigidly connected to the fan, the main shaft input end is installed with a speed sensor, the servo electric cylinder is electrically connected to the servo controller, the servo controller and the speed sensor are both electrically connected to the PLC programming controller; The negative feedback closed-loop control method comprises the following steps: the power of the fan is transmitted to the hydraulic pump, the speed sensor is responsible for monitoring the speed of the hydraulic pump, and the collected signal is transmitted to the PLC programming controller, the PLC programming controller quickly analyzes and processes the signal, generates corresponding control instructions according to the preset control strategy, and then sends the instructions to the servo driver, the servo driver accurately controls the movement of the servo electric cylinder according to the received instructions, and adjusts the swing angle of the hydraulic pump in real time by extending and retracting the servo electric cylinder. After the swing angle is adjusted, the output flow of the hydraulic pump also changes accordingly, and the speed of the hydraulic pump changes again and is captured by the speed sensor, and fed back to the system for a new round of adjustment, and this cycle is repeated to form a closed-loop real-time control process.

2. A negative feedback closed-loop control method for a constant flow hydraulic pump according to claim 1, characterized in that: The variable push rod is arranged on one side of the variable swing, and a return spring is arranged on the other side of the variable swing.

3. A negative feedback closed-loop control method for a constant flow hydraulic pump according to claim 2, characterized in that: The variable push rod and the return spring are symmetrically arranged on both sides of the main shaft, and the variable push rod and the return spring are distributed on the outside of the plunger.

4. A negative feedback closed-loop control method for a constant flow hydraulic pump according to claim 2 or 3, characterized in that: The active end of the servo electric cylinder extends, pushing the variable push rod on one side of the variable swing to move, causing the variable swing to swing, and the return spring on the other side of the variable swing to compress, so that the product of the displacement and speed of the hydraulic pump is constant at the initial set value; The active end of the servo electric cylinder is shortened, pulling the variable push rod on one side of the variable swing to move, the variable swing swings, and the return spring on the other side of the variable swing resets, so that the product of the displacement and speed of the hydraulic pump is constant at the initial set value.

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