A four-quadrant load device

Abstract

The present invention discloses a four-quadrant load device, including a hydraulic dynamometer, a variable frequency motor, a frequency converter matched with the variable frequency motor, and a host computer unit; the hydraulic dynamometer is directly connected to the variable frequency motor in series; the load output of the hydraulic dynamometer and the variable frequency motor is accurately controlled by a speed torque sensor, and the water volume of the hydraulic dynamometer inlet and outlet and the speed and torque output of the variable frequency motor are adjusted by the host computer unit to achieve the simulation of four load operating conditions of positive steering positive torque, positive steering negative torque, negative steering negative torque and negative steering positive torque. The four-quadrant load device has two working modes, namely, decentralized and combined, which can make the hydraulic dynamometer and the variable frequency motor operate separately or form a four-quadrant load operation mode by combining the two, and fully simulate the operating state of the actual ship propulsion system.

Description

Technical Field

[0001] The invention relates to the technical field of electric propulsion system detection, in particular to a four-quadrant load device. Background Art

[0002] With the development of modern science and technology, electric propulsion systems have begun to be used in the field of ship shipping. Due to the space limitations of ships, the scientific research and operation commissioning of ship electric propulsion systems generally need to be carried out on land. Therefore, how to simulate the operating conditions of ship electric propulsion systems on land has become a prominent issue in the test process of ship electric propulsion systems.

[0003] At present, the equipment for testing ship electric propulsion systems mainly uses four-quadrant loads, but the technical threshold itself is high. A four-quadrant load of 10 megawatts can easily cost more than 10 million yuan, and the related high-end equipment and control methods are monopolized by a few multinational companies, which limits its large-scale application in the field of ship electric propulsion testing. At the same time, since the ship's braking power does not exceed one-fourth of the propulsion power, the traditional four-quadrant motor plus inverter solution has a huge waste of system configuration under positive steering negative torque and negative steering positive torque operating conditions. In addition, the existing four-quadrant load will generate huge electrical energy when operating under positive steering positive torque and negative steering negative torque operating conditions. Under the test conditions where it is impossible to connect to the public power grid, how to deal with this electrical energy is another prominent contradiction. Summary of the invention

[0004] In view of the above problems and technical requirements, the inventors have proposed a four-quadrant load device. The technical solution of the present invention is as follows:

[0005] A four-quadrant load device includes a hydraulic dynamometer, a variable frequency motor, a frequency converter matched with the variable frequency motor, and a host computer unit; the hydraulic dynamometer and the variable frequency motor are directly connected in series; the working method of the four-quadrant load device includes:

[0006] The host computer unit determines the ship operating conditions simulated by the four-quadrant load;

[0007] When the four-quadrant load simulates the forward sailing or reverse reversing condition of the ship, the upper computer unit turns off the inverter and adjusts the output torque of the four-quadrant load by controlling the water inlet and outlet of the hydraulic dynamometer;

[0008] When the four-quadrant load simulates the ship braking condition, the host computer unit adjusts the output torque of the four-quadrant load by controlling the water inlet and outlet of the hydraulic dynamometer and the output voltage of the inverter, so that the speed-torque curve of the four-quadrant load meets the set braking curve.

[0009] Furthermore, the working method of the four-quadrant load device also includes:

[0010] When the four - quadrant load simulates the ship's fluctuating working conditions, the host computer unit controls the output torque of the hydraulic dynamometer to be a fixed value and adjusts the output voltage of the frequency converter so that the output torque of the frequency - conversion motor changes periodically.

[0011] Furthermore, controlling the water inflow and outflow of the hydraulic dynamometer includes:

[0012] When the four - quadrant load simulates the ship's forward - sailing working conditions, the host computer unit controls the hydraulic dynamometer to open the forward water - inlet valve and the forward water - outlet valve, and controls the water inflow and outflow of the hydraulic dynamometer by adjusting the opening of the valves;

[0013] When the four - quadrant load simulates the ship's reverse - backing working conditions, the host computer unit controls the hydraulic dynamometer to open the reverse water - inlet valve and the reverse water - outlet valve, and controls the water inflow and outflow of the hydraulic dynamometer by adjusting the opening of the valves.

[0014] Furthermore, if the host computer unit includes a hydraulic - dynamometer control unit and a frequency - converter control unit, then when the four - quadrant load simulates the ship's forward - sailing or reverse - backing working conditions, the hydraulic - dynamometer control unit is used to control the water inflow and outflow of the hydraulic dynamometer, and the frequency - converter control unit is used to turn off the frequency converter.

[0015] Furthermore, if the host computer unit includes a centralized control unit, then when the four - quadrant load simulates the ship's braking working conditions, the centralized control unit is used to control the water inflow and outflow of the hydraulic dynamometer and the output voltage of the frequency converter.

[0016] Furthermore, the four - quadrant load simulating the ship's forward - sailing working conditions means that the four - quadrant load operates in the positive - rotation positive - torque mode; the four - quadrant load simulating the ship's reverse - backing working conditions means that the four - quadrant load operates in the negative - rotation negative - torque mode.

[0017] Furthermore, the four - quadrant load simulating the ship's braking working conditions includes simulating the ship's forward - braking working conditions and reverse - braking working conditions; when the four - quadrant load simulates the ship's forward - braking working conditions, the operating states of the four - quadrant load include the positive - rotation positive - torque mode stage and the positive - rotation negative - torque mode stage; when the four - quadrant load simulates the ship's reverse - braking working conditions, the operating states of the four - quadrant load include the negative - rotation negative - torque mode stage and the negative - rotation positive - torque mode stage.

[0018] Furthermore, when simulating the ship's braking working conditions, the host computer unit adjusts the output torque of the four - quadrant load by controlling the water inflow and outflow of the hydraulic dynamometer and the output voltage of the frequency converter, so that the speed - torque curve of the four - quadrant load meets the set braking curve, including:

[0019] When the four - quadrant load operates in the positive - rotation positive - torque mode or the negative - rotation negative - torque mode stage, the host computer unit adjusts the output torque of the hydraulic dynamometer by controlling the water inflow and outflow of the hydraulic dynamometer;

[0020] The rotational speed and torque sensor detects the output torque and the current rotational speed of the four - quadrant load in real - time and transmits them to the upper computer unit;

[0021] The upper computer unit calculates the difference between the output torque of the four - quadrant load and the torque corresponding to the current rotational speed in the set braking curve;

[0022] According to the difference, the upper computer unit adjusts the output torque of the variable - frequency motor by controlling the output voltage of the frequency converter, so that the output torque of the four - quadrant load meets the torque corresponding to the current rotational speed in the set braking curve;

[0023] When the four - quadrant load operates in the positive - rotation negative - torque mode or the negative - rotation positive - torque mode stage, the upper computer unit controls the hydraulic dynamometer not to do work, and adjusts the output torque of the variable - frequency motor by controlling the output voltage of the frequency converter, so that the rotational speed - torque curve output by the four - quadrant load meets the set braking curve.

[0024] Furthermore, the upper computer unit controls the output torque of the hydraulic dynamometer to be a fixed value, and adjusts the output voltage of the frequency converter so that the output torque of the variable - frequency motor changes periodically, including:

[0025] The upper computer unit adjusts the inflow and outflow water volume of the hydraulic dynamometer so that the output torque of the hydraulic dynamometer is fixed at the positive maximum peak value of the torque fluctuation waveform;

[0026] The upper computer unit controls the output torque of the variable - frequency motor to fluctuate between 0 and the difference between the positive maximum value and the negative maximum value of the torque fluctuation waveform by adjusting the output voltage of the frequency converter.

[0027] Furthermore, the rated power of the variable - frequency motor is not greater than one - quarter of the rated power of the hydraulic dynamometer.

[0028] The beneficial technical effects of the present invention are:

[0029] The present invention discloses a four - quadrant load device, which can adjust the inflow and outflow water volume of the hydraulic dynamometer and the rotational speed and torque output by the variable - frequency motor through the upper computer unit, and realize the simulation of four load operation conditions: positive - rotation positive - torque, positive - rotation negative - torque, negative - rotation negative - torque, and negative - rotation positive - torque; the device has two working modes: decentralized and combined, and can make the hydraulic dynamometer and the variable - frequency motor operate alone or form a four - quadrant load operation mode by combining the two, so as to comprehensively simulate the operation state of the actual ship propulsion system. At the same time, the configuration of the power of the variable - frequency motor and the power of the hydraulic dynamometer is flexible, the equipment cost is low, the upgrade is convenient, and it is easy to implement technically. Furthermore, since the motor of this four - quadrant load is always in the torque output state and only obtains energy from the power grid, complex grid - connection problems are avoided. Brief Description of the Drawings

[0030] Figure 1It is a schematic structural diagram of the four-quadrant load device of the present invention.

[0031] Figure 2 It is a schematic diagram of the operating principle of the four-quadrant load of the present invention. Specific embodiments

[0032] The following further describes the specific embodiments of the present invention with reference to the accompanying drawings.

[0033] The present invention discloses a four-quadrant load device. Please combine Figure 1 , which mainly includes a hydraulic dynamometer 1, a variable-frequency motor 2, an inverter connected in supporting with the variable-frequency motor, and a host computer unit. Preferably, the host computer unit includes a hydraulic dynamometer control unit, an inverter control unit, and a centralized control unit; the hydraulic dynamometer 1 is directly connected in series with the variable-frequency motor 2; the working method of the four-quadrant load device mainly includes:

[0034] (1) The host computer unit determines the ship operating conditions simulated by the four-quadrant load; wherein, the ship operating conditions include ship forward navigation, reverse backing, forward braking, reverse braking, and ship fluctuations, etc.

[0035] (2) When the four-quadrant load simulates the ship forward navigation or reverse backing conditions, the host computer unit turns off the inverter and adjusts the output torque of the four-quadrant load by controlling the water inflow and outflow of the hydraulic dynamometer; at this time, the variable-frequency motor only rotates following the hydraulic dynamometer and does not work, while the hydraulic dynamometer is in an independent operating state, and the water flows through the hydraulic dynamometer to consume energy;

[0036] Specifically, the four-quadrant load simulating the ship forward navigation condition is that the four-quadrant load operates in the positive rotation and positive torque mode; the four-quadrant load simulating the ship reverse backing condition is that the four-quadrant load operates in the negative rotation and negative torque mode;

[0037] When the four-quadrant load simulates the ship forward navigation condition, the inverter control unit turns off the inverter, and the hydraulic dynamometer control unit controls the hydraulic dynamometer to open the forward water inlet valve and the forward water outlet valve, and controls the water inflow and outflow of the hydraulic dynamometer by adjusting the opening of the valve;

[0038] When the four-quadrant load simulates the ship reverse backing condition, the inverter control unit turns off the inverter; the hydraulic dynamometer control unit controls the hydraulic dynamometer to open the reverse water inlet valve and the reverse water outlet valve, and controls the water inflow and outflow of the hydraulic dynamometer by adjusting the opening of the valve.

[0039] (3) When the four - quadrant load simulates the ship braking condition, the host computer unit adjusts the output torque of the four - quadrant load by controlling the water inflow and outflow of the hydraulic dynamometer and the output voltage of the frequency converter, so that the speed - torque curve of the four - quadrant load meets the set braking curve; among them, the set braking curve is determined by relevant parameters such as the tonnage of the ship to be simulated, and this braking curve is the relationship curve between the speed and torque of the ship's propeller; the speed of the four - quadrant load is determined by the tested propulsion equipment and is consistent with the speed in the set braking curve.

[0040] Specifically, the four - quadrant load simulating the ship braking condition includes simulating the ship's forward braking condition and reverse braking condition; during the simulation of the forward braking process, since it simulates the process of the ship's propeller gradually decelerating during actual navigation, at this time, the operating state of the four - quadrant load is in the stage of positive rotation and positive torque. And due to the large inertia of the hull, after the ship's propeller no longer does work on the water, the water flow will continue to push the propeller to rotate forward, and at this time, the situation where the water flow does work on the propeller occurs, that is, the stage of positive rotation and negative torque appears; similarly, during the simulation of the reverse braking process, the operating state of the four - quadrant load includes the stage of negative rotation and negative torque mode and the stage of negative rotation and positive torque mode.

[0041] When the four - quadrant load operates in the positive rotation and positive torque mode or negative rotation and negative torque mode stage, the centralized control unit adjusts the output torque of the hydraulic dynamometer by controlling the water inflow and outflow of the hydraulic dynamometer.

[0042] The speed - torque sensor detects the output torque and the current speed of the four - quadrant load in real - time and transmits them to the centralized control unit.

[0043] The centralized control unit calculates the difference between the output torque of the four - quadrant load and the torque corresponding to the current speed in the set braking curve.

[0044] According to this difference, the centralized control unit adjusts the output torque of the frequency - conversion motor by controlling the output voltage of the frequency converter, so that the output torque of the four - quadrant load meets the torque corresponding to the current speed in the set braking curve.

[0045] When the four - quadrant load operates in the positive rotation and negative torque mode or negative rotation and positive torque mode stage, the centralized control unit controls the inlet valve of the hydraulic dynamometer to be fully closed and the outlet valve to be fully open, so that the hydraulic dynamometer is in a follow - up state of not doing work, and adjusts the output torque of the frequency - conversion motor by controlling the output voltage of the frequency converter, so that the speed - torque curve output by the four - quadrant load meets the set braking curve.

[0046] Preferably, the working method of the four - quadrant load device further includes;

[0047] When the four-quadrant load simulates the ship's fluctuating working condition, the upper computer unit controls the output torque of the hydraulic dynamometer to be a fixed value, and adjusts the output voltage of the frequency converter so that the output torque of the variable frequency motor changes periodically; preferably, the hydraulic dynamometer and the frequency converter are controlled by a centralized control unit;

[0048] Specifically, the upper computer unit adjusts the water inlet and outlet of the hydraulic dynamometer so that the output torque of the hydraulic dynamometer is fixed to the maximum positive peak value of the torque fluctuation waveform;

[0049] The host computer unit controls the output torque of the variable frequency motor to fluctuate between 0 and the difference between the positive maximum value and the negative maximum value of the torque fluctuation waveform by adjusting the output voltage of the inverter, thereby realizing the working condition in which the four-quadrant load output changes periodically around a fixed value.

[0050] Preferably, the rated power of the variable frequency motor is not greater than one quarter of the rated power of the hydraulic dynamometer.

[0051] The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A four-quadrant load device, characterized in that, It includes a hydraulic dynamometer, a variable-frequency motor, a frequency converter connected in a supporting manner with the variable-frequency motor, and a host computer unit; the hydraulic dynamometer is directly connected in series with the variable-frequency motor on the same axis; the working method of the four-quadrant load device includes: The host computer unit determines the ship operation conditions simulated by the four-quadrant load. When the four-quadrant load simulates the forward sailing or reverse backing conditions of the ship, the host computer unit turns off the frequency converter and adjusts the output torque of the four-quadrant load by controlling the water inflow and outflow of the hydraulic dynamometer. When the four-quadrant load simulates the braking condition of the ship, the host computer unit adjusts the output torque of the four-quadrant load by controlling the water inflow and outflow of the hydraulic dynamometer and the output voltage of the frequency converter, so that the speed-torque curve of the four-quadrant load meets the set braking curve, including: When the four-quadrant load operates in the positive rotation positive torque mode or negative rotation negative torque mode stage, the host computer unit adjusts the output torque of the hydraulic dynamometer by controlling the water inflow and outflow of the hydraulic dynamometer. The speed-torque sensor detects the output torque and the current speed of the four-quadrant load in real time and transmits them to the host computer unit. The host computer unit calculates the difference between the output torque of the four-quadrant load and the torque corresponding to the current speed in the set braking curve. According to the difference, the host computer unit adjusts the output torque of the variable-frequency motor by controlling the output voltage of the frequency converter, so that the output torque of the four-quadrant load meets the torque corresponding to the current speed in the set braking curve. When the four-quadrant load operates in the positive rotation negative torque mode or negative rotation positive torque mode stage, the host computer unit controls the hydraulic dynamometer not to do work and adjusts the output torque of the variable-frequency motor by controlling the output voltage of the frequency converter, so that the speed-torque curve output by the four-quadrant load meets the set braking curve.

2. The four-quadrant load device according to claim 1, wherein The working method of the four-quadrant load device further includes; When the four-quadrant load simulates the ship fluctuation condition, the host computer unit controls the output torque of the hydraulic dynamometer to be a fixed value and adjusts the output voltage of the frequency converter so that the output torque of the variable-frequency motor changes periodically.

3. The quadrant load device according to claim 1, wherein The control of the water inflow and outflow of the hydraulic dynamometer includes: When the four-quadrant load simulates the forward sailing condition of the ship, the host computer unit controls the hydraulic dynamometer to open the forward water inlet valve and the forward water outlet valve and controls the water inflow and outflow of the hydraulic dynamometer by adjusting the valve opening. When the four-quadrant load simulates the reverse backing condition of the ship, the host computer unit controls the hydraulic dynamometer to open the reverse water inlet valve and the reverse water outlet valve and controls the water inflow and outflow of the hydraulic dynamometer by adjusting the valve opening.

4. The four-quadrant load device according to claim 1 or 3, characterized in that, The host computer unit includes a hydraulic dynamometer control unit and a frequency converter control unit. When the four-quadrant load simulates the forward sailing or reverse backing conditions of the ship, the hydraulic dynamometer control unit is used to control the water inflow and outflow of the hydraulic dynamometer, and the frequency converter control unit is used to turn off the frequency converter.

5. The quadrant load device according to claim 1, characterized in that, The host computer unit includes a centralized control unit. When the four-quadrant load simulates the ship braking condition, the centralized control unit is used to control the water inflow and outflow of the hydraulic dynamometer and the output voltage of the frequency converter.

6. The four-quadrant load device according to claim 1, wherein The four-quadrant load simulating the ship's forward sailing condition is that the four-quadrant load operates in the positive rotation and positive torque mode; the four-quadrant load simulating the ship's reverse braking condition is that the four-quadrant load operates in the negative rotation and negative torque mode.

7. The four-quadrant load device according to claim 1, characterized in that, The four-quadrant load simulating the ship braking condition includes simulating the ship's forward braking condition and reverse braking condition; when the four-quadrant load simulates the ship's forward braking condition, the operating states of the four-quadrant load include the positive rotation and positive torque mode stage and the positive rotation and negative torque mode stage; when the four-quadrant load simulates the ship's reverse braking condition, the operating states of the four-quadrant load include the negative rotation and negative torque mode stage and the negative rotation and positive torque mode stage.

8. The four-quadrant load device according to claim 2, characterized in that, The host computer unit controls the output torque of the hydraulic dynamometer to be a fixed value and adjusts the output voltage of the frequency converter so that the output torque of the frequency conversion motor changes periodically, including: The host computer unit adjusts the water inflow and outflow of the hydraulic dynamometer so that the output torque of the hydraulic dynamometer is fixed at the positive maximum peak of the torque fluctuation waveform; The host computer unit controls the output torque of the frequency conversion motor to fluctuate between 0 and the difference between the positive maximum value and the negative maximum value of the torque fluctuation waveform by adjusting the output voltage of the frequency converter.

9. The four-quadrant load device according to claim 1, wherein The rated power of the frequency conversion motor is not greater than one-fourth of the rated power of the hydraulic dynamometer.

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