Equivalent test device and method for exploring gravity energy storage power characteristics

Abstract

The invention provides an equivalent test device and method for exploring gravity energy storage power characteristics. The device is characterized in that a test circuit is connected with an upper computer after being connected to a power grid; the test circuit is built based on a gravity energy storage grid-connected type and is used for outputting a torque curve corresponding to an equivalent torque curve signal of gravity energy storage so as to equivalently convert the reference power of the gravity energy storage into the torque of a motor for an equivalent test; the upper computer is used for generating a torque curve signal based on the reference power of gravity energy storage and writing the torque curve signal into the test circuit; and measuring the network side power of the test circuit in the test as a test result. According to the invention, the topological structure can be flexibly changed according to the gravity energy storage grid-connected type so as to be suitable for equivalent tests of different gravity energy storage grid-connected schemes; limitation of a gravity energy storage test site can be overcome, power characteristics of the gravity energy storage system in steady-state operation under different grid-connected topologies can be truly restored, equivalent tests of gravity energy storage technologies of different power levels can be carried out, and the accuracy of power test data can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric energy storage, and in particular to an equivalent test device and method for exploring the power characteristics of gravity energy storage. Background Art

[0002] Gravity energy storage is a form of mechanical energy storage. Its main principle is to use surplus electrical energy to lift a gravity block for "charging." When electricity consumption peaks, the gravity block is lowered and gravity is used to "discharge" the block, thereby providing electricity to the grid. Gravity energy storage technology can be divided into two technical routes: vertical gravity energy storage technology and slope gravity energy storage technology. Vertical gravity energy storage technology can be further divided into above-ground building type and underground mine type. Slope gravity energy storage technology is usually built on mountainous terrain. However, regardless of the technical route of gravity energy storage, there are problems with large project footprints and complex systems. Even if a gravity energy storage system with a capacity of hundreds of kilowatts is to be built, in addition to the large footprint, a height difference of hundreds of meters is required. Therefore, it is impossible to conduct gravity energy storage tests on actual sites.

[0003] To address the limited testing site for gravity energy storage, researchers have proposed using a scaled-down method to explore the power characteristics of gravity energy storage. This allows for an equivalent restoration of the gravity energy storage system to obtain relevant data. However, while existing equivalent testing methods can overcome site limitations, they still suffer from low accuracy and limited flexibility. They are unable to accurately restore the power characteristics of gravity energy storage systems in steady-state operation under different grid-connected topologies, making equivalent testing of gravity energy storage technologies at different power levels impossible. Summary of the Invention

[0004] In order to solve the problem of low flexibility of the existing gravity energy storage test technology, the present invention proposes an equivalent test device for exploring the power characteristics of gravity energy storage, including: a test circuit and a host computer 7;

[0005] The test circuit is connected to the host computer 7 after being connected to the power grid;

[0006] The test circuit is built based on the gravity energy storage grid-connected type and is used to output a torque curve corresponding to the equivalent torque curve signal of the gravity energy storage, so as to convert the reference power of the gravity energy storage into the torque of the motor to perform an equivalent test on the power characteristics of the gravity energy storage;

[0007] The host computer 7 is configured to generate the torque curve signal based on the reference power of the gravity energy storage, and write the torque curve signal into the test circuit; and measure the grid-side power of the test circuit in the equivalent test as the result of the equivalent test;

[0008] The types of gravity energy storage grid connection include direct grid connection through synchronous motors, grid connection through doubly-fed motors, and grid connection through full-power converters.

[0009] Preferably, the test circuit comprises: a torque sensor 1, a permanent magnet synchronous motor 2, a wound rotor motor 3, a first four-quadrant frequency converter 4, a second four-quadrant frequency converter 5 and a coupling 6;

[0010] The permanent magnet synchronous motor 2, the torque sensor 1 and the wound rotor motor 3 are connected in sequence via a coupling 6;

[0011] When the gravity energy storage grid-connected type is gravity energy storage directly connected to the grid through a synchronous motor or connected to the grid through a doubly fed motor, the permanent magnet synchronous motor 2 is connected to the first four-quadrant frequency converter 4, the rotor side of the winding-rotor motor 3 is connected to the second four-quadrant frequency converter 5, and the winding-rotor motor 3 is also connected to the power grid; when the gravity energy storage grid-connected type is gravity energy storage connected to the grid through a full-power converter, the permanent magnet synchronous motor 2 is connected to the second four-quadrant frequency converter 5, the winding-rotor motor 3 is connected to the first four-quadrant frequency converter 4, and the rotor side of the winding-rotor motor 3 is short-circuited;

[0012] The first four-quadrant frequency converter 4 and the second four-quadrant frequency converter 5 are both connected to the power grid; the first four-quadrant frequency converter 4 is connected to the host computer 7, and is used to calculate the torque curve based on the equivalent torque curve signal and input it into the directly connected permanent magnet synchronous motor 2 or the winding-rotor motor 3, and perform the equivalent test by controlling the operation of the directly connected permanent magnet synchronous motor 2 or the winding-rotor motor 3; the second four-quadrant frequency converter 5 is used to perform excitation control on the directly connected permanent magnet synchronous motor 2 or the winding-rotor motor 3, so that the permanent magnet synchronous motor 2 and the winding-rotor motor 3 are dragged to perform the equivalent test; the grid-connected side of the second four-quadrant frequency converter 5 is also connected to the host computer 7;

[0013] The torque sensor 1 is connected to the host computer 7;

[0014] The capacities of the permanent magnet synchronous motor 2 and the wound rotor motor 3 are determined based on the reference power of the gravity energy storage.

[0015] Preferably, the first four-quadrant frequency converter 4 is specifically used for:

[0016] calculating the torque curve based on the equivalent torque curve signal;

[0017] When the gravity energy storage grid-connected type is direct grid-connected through a synchronous motor or grid-connected through a doubly-fed motor, the torque curve is input into the permanent magnet synchronous motor 2 to control the permanent magnet synchronous motor 2 to operate in a torque control mode to perform the equivalent test;

[0018] When the gravity energy storage grid-connected type is gravity energy storage connected to the grid via a full-power converter, the torque curve is input into the winding motor 3 to control the operation of the winding motor 3 in a torque control mode, and the torque curve is output to the permanent magnet synchronous motor 2 for the equivalent test.

[0019] Preferably, the second four-quadrant frequency converter 5 is specifically used for:

[0020] When the gravity energy storage grid-connected type is direct grid-connected gravity energy storage through a synchronous motor, a DC excitation is applied to the rotor side of the wound-rotor motor 3 to simulate the characteristics of an electrically excited synchronous motor so that the permanent magnet synchronous motor 2 and the wound-rotor motor 3 are subjected to the equivalent test;

[0021] When the gravity energy storage grid-connected type is gravity energy storage grid-connected through a doubly-fed generator, AC excitation is passed to the rotor side of the winding-rotor motor 3 and vector control is applied to enable the permanent magnet synchronous motor 2 and the winding-rotor motor 3 to perform the equivalent test.

[0022] Preferably, the host computer 7 is specifically used for:

[0023] An equivalent torque curve expression of gravity energy storage is obtained based on the reference power calculation of gravity energy storage, and the torque curve expression is converted into the torque curve signal and written into the first four-quadrant inverter 4; and is used to obtain the grid-side power of the grid-connected side of the second four-quadrant inverter 5 as the result of the equivalent test.

[0024] Preferably, the torque curve expression is expressed as follows:

[0025]

[0026] Where, T L is the torque converted from gravitational potential energy, η c is the transmission efficiency, M is the mass of the weight, g is the acceleration of gravity, v is the speed of the weight, θ is the angle between the slope where the gravity energy storage is located and the horizontal plane, ω w is the mechanical angular velocity of the motor, and j is the speed ratio.

[0027] Preferably, the host computer 7 is further used for:

[0028] Obtaining parameters of the torque sensor 1 and the first four-quadrant frequency converter 4 in the equivalent test;

[0029] Adjusting the torque curve signal based on the parameter and sending the signal to the first four-quadrant frequency converter 4 to control the first four-quadrant frequency converter 4 to stably output the torque curve equivalent to the reference power of the gravity energy storage;

[0030] The parameters include mechanical torque, mechanical power and motor speed.

[0031] In another aspect, the present invention further provides an equivalent test method for exploring the power characteristics of gravity energy storage, wherein the method uses the above-mentioned equivalent test device for exploring the power characteristics of gravity energy storage to perform an equivalent test of the power characteristics of gravity energy storage, and the method comprises:

[0032] Based on the reference power of the gravity energy storage, an equivalent torque curve signal of the gravity energy storage is generated by the host computer 7, and the torque curve signal is written into the test circuit;

[0033] Outputting a torque curve corresponding to the torque curve signal through the test circuit to equivalently convert the reference power of the gravity energy storage into the torque of the motor to perform an equivalent test on the power characteristics of the gravity energy storage;

[0034] Measuring the grid-side power of the test circuit by the host computer 7 in the equivalent test as a result of the equivalent test;

[0035] Among them, the test circuit is built based on the gravity energy storage grid-connected type; the gravity energy storage grid-connected type includes gravity energy storage directly connected to the grid through a synchronous motor, connected to the grid through a doubly fed motor, and connected to the grid through a full power converter.

[0036] Preferably, the test circuit outputs a torque curve corresponding to the torque curve signal to convert the reference power of the gravity energy storage into the torque of the motor to perform an equivalent test on the power characteristics of the gravity energy storage, including:

[0037] Based on the equivalent torque curve signal, the torque curve is calculated by the first four-quadrant frequency converter 4 in the test circuit, and is input into the directly connected permanent magnet synchronous motor 2 or the wound-rotor motor 3 to control the directly connected permanent magnet synchronous motor 2 or the wound-rotor motor 3 to operate and perform the equivalent test;

[0038] The excitation control of the directly connected permanent magnet synchronous motor 2 or winding rotor motor 3 is performed through the second four-quadrant frequency converter 5 in the test circuit, so that the permanent magnet synchronous motor 2 and winding rotor motor 3 can be driven to perform the equivalent test.

[0039] Preferably, the torque curve is calculated by the first four-quadrant frequency converter 4 in the test circuit, and is input into the directly connected permanent magnet synchronous motor 2 or the wound-rotor motor 3 to control the directly connected permanent magnet synchronous motor 2 or the wound-rotor motor 3 to perform the equivalent test, including:

[0040] When the gravity energy storage grid-connected type is direct grid-connected through a synchronous motor or grid-connected through a doubly-fed motor, the torque curve is calculated by the first four-quadrant inverter 4 and input into the permanent magnet synchronous motor 2, so as to control the permanent magnet synchronous motor 2 to operate in a torque control mode to perform the equivalent test;

[0041] When the gravity energy storage grid-connected type is gravity energy storage connected to the grid via a full-power converter, the torque curve is calculated by the first four-quadrant inverter 4 and input into the winding motor 3 to control the operation of the winding motor 3 in the torque control mode, and the torque curve is output to the permanent magnet synchronous motor 2 for the equivalent test.

[0042] Preferably, the excitation control of the directly connected permanent magnet synchronous motor 2 or the winding-rotor motor 3 is performed by the second four-quadrant frequency converter 5 in the test circuit, so that the permanent magnet synchronous motor 2 and the winding-rotor motor 3 are subjected to the equivalent test, including:

[0043] When the gravity energy storage grid-connected type is direct grid-connected gravity energy storage through a synchronous motor, a DC excitation is applied to the rotor side of the wound-rotor motor 3 through the second four-quadrant inverter 5 to simulate the characteristics of an electrically excited synchronous motor so that the permanent magnet synchronous motor 2 and the wound-rotor motor 3 are subjected to the equivalent test;

[0044] When the gravity energy storage grid-connected type is gravity energy storage grid-connected through a doubly-fed generator, AC excitation is passed to the rotor side of the winding-rotor motor 3 through the second four-quadrant inverter 5 and vector control is applied to enable the permanent magnet synchronous motor 2 and the winding-rotor motor 3 to perform the equivalent test.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention provides an equivalent test device and method for exploring the power characteristics of gravity energy storage, the device comprising: a test circuit and a host computer 7; the test circuit is connected to the host computer 7 after being connected to the power grid; the test circuit is constructed based on the grid-connected type of gravity energy storage, and is used to output a torque curve corresponding to an equivalent torque curve signal of the gravity energy storage, so as to convert the reference power of the gravity energy storage into the torque of the motor for an equivalent test of the power characteristics of the gravity energy storage; the host computer 7 is used to generate the torque curve signal based on the reference power of the gravity energy storage, and write the torque curve signal into the test circuit; and measure the grid-side power of the test circuit in the equivalent test as the equivalent test The results of the test are presented; wherein, the types of gravity energy storage grid connection include direct grid connection of gravity energy storage through a synchronous motor, grid connection through a doubly fed motor, and grid connection through a full power converter; the device proposed in the present invention can flexibly change the topology structure on the basis of existing equipment according to the different types of gravity energy storage grid connection, so as to be applicable to equivalent tests of different gravity energy storage grid connection schemes; the present invention converts the reference power of gravity energy storage into the torque of the motor for equivalent testing, which can overcome the limitations of the gravity energy storage test site and truly restore the power characteristics of the gravity energy storage system in steady-state operation under different grid-connected topologies, and conduct equivalent tests of gravity energy storage technologies with different power levels, thereby achieving the purpose of improving the accuracy of power equivalent test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A structural diagram of an equivalent test device for exploring the power characteristics of gravity energy storage provided by the present invention when the gravity energy storage is directly connected to the grid through a synchronous motor or a doubly fed generator;

[0048] Figure 2 A structural diagram of an equivalent test device for exploring the power characteristics of gravity energy storage provided by the present invention when the gravity energy storage is connected to the grid via a full-power converter;

[0049] Figure 3 A flow chart of an equivalent test method for exploring the power characteristics of gravity energy storage provided by the present invention;

[0050] Figure 4 A schematic diagram of the structure of conventional gravity energy storage provided by the present invention;

[0051] Figure 5 This is a schematic diagram of the equivalent topology of the conventional gravity energy storage system provided by the present invention;

[0052] Explanation of the accompanying figures: 1-torque sensor, 2-permanent magnet synchronous motor, 3-wound-rotor motor, 4-first four-quadrant inverter, 5-second four-quadrant inverter, 6-coupling, 7-host computer. DETAILED DESCRIPTION

[0053] The present invention proposes an equivalent test device and method for exploring the power characteristics of gravity energy storage, so as to facilitate the study of the power characteristics of gravity energy storage under different grid-connected topologies.

[0054] In order to better understand the present invention, the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0055] Example 1:

[0056] An equivalent test device for exploring the power characteristics of gravity energy storage, the structural diagram of which is shown in the figure Figure 1 As shown, it includes: a test circuit and a host computer 7;

[0057] The test circuit is connected to the host computer 7 after being connected to the power grid;

[0058] The test circuit is built based on the gravity energy storage grid-connected type and is used to output a torque curve corresponding to the equivalent torque curve signal of the gravity energy storage, so as to convert the reference power of the gravity energy storage into the torque of the motor to perform an equivalent test on the power characteristics of the gravity energy storage;

[0059] The host computer 7 is configured to generate the torque curve signal based on the reference power of the gravity energy storage, and write the torque curve signal into the test circuit; and measure the grid-side power of the test circuit in the equivalent test as the result of the equivalent test;

[0060] The types of gravity energy storage grid connection include direct grid connection through synchronous motors, grid connection through doubly-fed motors, and grid connection through full-power converters.

[0061] The test circuit includes: a torque sensor 1, a permanent magnet synchronous motor 2, a wound rotor motor 3, a first four-quadrant frequency converter 4, a second four-quadrant frequency converter 5 and a coupling 6;

[0062] The permanent magnet synchronous motor 2, the torque sensor 1 and the wound rotor motor 3 are connected in sequence via a coupling 6;

[0063] The torque sensor 1 is connected to the host computer 7;

[0064] The first four-quadrant frequency converter 4 and the second four-quadrant frequency converter 5 are both connected to the power grid; the first four-quadrant frequency converter 4 is connected to the host computer 7; the grid-connected side of the second four-quadrant frequency converter 5 is also connected to the host computer 7;

[0065] The capacities of the permanent magnet synchronous motor 2 and the wound rotor motor 3 are determined based on the reference power of the gravity energy storage.

[0066] When the gravity energy storage grid-connected type is gravity energy storage directly connected to the grid through a synchronous motor or connected to the grid through a doubly fed motor, the permanent magnet synchronous motor 2 is connected to the first four-quadrant frequency converter 4, the rotor side of the winding motor 3 is connected to the second four-quadrant frequency converter 5, and the winding motor 3 is also connected to the grid, that is, Figure 1 connection method.

[0067] When the gravity energy storage grid-connected type is direct grid-connected gravity energy storage through a synchronous motor or grid-connected through a doubly fed motor, the permanent magnet synchronous motor 2 is used as a torque simulation motor for gravity energy storage, the wound-rotor motor 3 is used as a generator / motor for gravity energy storage, the second four-quadrant frequency converter 5 is used as an excitation converter, and the first four-quadrant frequency converter 4 is used as a torque control converter.

[0068] When the gravity energy storage grid-connected type is gravity energy storage directly connected to the grid through a synchronous motor or connected to the grid through a doubly fed motor, the first four-quadrant frequency converter 4 calculates the torque curve based on the equivalent torque curve signal and inputs the torque curve into the permanent magnet synchronous motor 2 to control the operation of the permanent magnet synchronous motor 2 in the torque control mode to perform the equivalent test. When the gravity energy storage grid-connected type is gravity energy storage directly connected to the grid through a synchronous motor, the second four-quadrant frequency converter 5 is used to pass DC excitation to the rotor side of the winding motor 3 to simulate the characteristics of the electrically excited synchronous motor so that the permanent magnet synchronous motor 2 and the winding motor 3 can be dragged to perform the equivalent test; when the gravity energy storage grid-connected type is gravity energy storage connected to the grid through a doubly fed motor, the second four-quadrant frequency converter 5 is used to pass AC excitation to the rotor side of the winding motor 3 and apply vector control so that the permanent magnet synchronous motor 2 and the winding motor 3 can be dragged to perform the equivalent test.

[0069] When the gravity energy storage grid-connected type is gravity energy storage grid-connected via a full-power converter, the permanent magnet synchronous motor 2 is connected to the second four-quadrant frequency converter 5, the winding motor 3 is connected to the first four-quadrant frequency converter 4, and the rotor side of the winding motor 3 is short-circuited. The structural diagram under this gravity energy storage grid-connected type is as follows: Figure 2 shown.

[0070] When the gravity energy storage grid-connected type is gravity energy storage connected to the grid via a full-power converter, the permanent magnet synchronous motor 2 is used as a generator / motor, the wound-rotor motor 3 is used as a torque simulation motor for gravity energy storage, the second four-quadrant frequency converter 5 is used as a grid-connected converter, and the first four-quadrant frequency converter 4 is used as a torque control converter.

[0071] When the gravity energy storage grid-connected type is gravity energy storage connected to the grid via a full-power converter, the first four-quadrant inverter 4 calculates the torque curve based on the equivalent torque curve signal, and inputs the torque curve into the winding motor 3 to control the operation of the winding motor 3 in the torque control mode, and outputs the torque curve to the permanent magnet synchronous motor 2 for the equivalent test.

[0072] The host computer 7 is specifically used to calculate the expression of the torque curve of the gravity energy storage that needs to be input to the torque simulation motor (that is, the equivalent torque curve expression of the gravity energy storage) based on the power instruction of the gravity energy storage (that is, the reference power), and convert the torque curve expression into the torque curve signal and write it into the first four-quadrant inverter 4; and to obtain the grid-side power of the grid-connected side of the second four-quadrant inverter 5 as the result of the equivalent test.

[0073] The host computer 7 is further configured to obtain parameters of the torque sensor 1 and the first four-quadrant frequency converter 4 in the equivalent test; adjust the torque curve signal based on the parameters and send the signal to the first four-quadrant frequency converter 4 to control the first four-quadrant frequency converter 4 to stably output the torque curve equivalent to the reference power of the gravity energy storage;

[0074] The parameters include mechanical torque, mechanical power and motor speed.

[0075] Furthermore, the device provided by the present invention can also incorporate a PLC as a slave computer. The PLC is connected to the master computer 7 and is also connected to the grid-connected sides of the torque sensor 1, the first four-quadrant inverter 4, and the second four-quadrant inverter 5. The PLC serves as a transmitter and receiver. Specifically, it is used to receive the torque curve signal from the host computer 7 and write the torque curve signal into the first four-quadrant frequency converter 4; and to obtain the grid-side power of the grid-connected side of the second four-quadrant frequency converter 5, and upload it to the host computer 7 as the result of the equivalent test; it is also used to obtain the parameters of the torque sensor 1 and the first four-quadrant frequency converter 4 in the equivalent test and upload them to the host computer 7, and the host computer 7 analyzes and calculates the parameters of the torque sensor 1 and the first four-quadrant frequency converter 4 to generate a new torque curve signal. The PLC receives the new torque curve signal and sends it to the first four-quadrant frequency converter 4 to control the first four-quadrant frequency converter 4 to stably output the torque curve equivalent to the reference power of the gravity energy storage.

[0076] The device proposed in the present invention can flexibly change the topology structure based on existing equipment according to the different types of gravity energy storage grid-connected schemes, so as to be suitable for equivalent tests of different gravity energy storage grid-connected schemes; the present invention converts the reference power of gravity energy storage into the torque of the motor for equivalent testing, which can overcome the limitations of the gravity energy storage test site and truly restore the power characteristics of the gravity energy storage system under different grid-connected topologies during steady-state operation, and conduct equivalent tests of gravity energy storage technologies with different power levels, thereby achieving the purpose of improving the accuracy of power equivalent test data.

[0077] Example 2:

[0078] Based on the same inventive concept, the present invention also provides an equivalent test method for exploring the power characteristics of gravity energy storage. The method uses an equivalent test device for exploring the power characteristics of gravity energy storage described in Example 1 to perform an equivalent test of the power characteristics of gravity energy storage. The flow chart is as follows: Figure 3 As shown, the method includes:

[0079] Step 1. Based on the reference power of the gravity energy storage, an equivalent torque curve signal of the gravity energy storage is generated by the host computer 7, and the torque curve signal is written into the test circuit;

[0080] Step 2. Outputting a torque curve corresponding to the torque curve signal through the test circuit to convert the reference power of the gravity energy storage into the torque of the motor to perform an equivalent test on the power characteristics of the gravity energy storage;

[0081] Step 3. Measuring the grid-side power of the test circuit in the equivalent test by the host computer 7 as the result of the equivalent test;

[0082] Among them, the test circuit is built based on the gravity energy storage grid-connected type; the gravity energy storage grid-connected type includes gravity energy storage directly connected to the grid through a synchronous motor, connected to the grid through a doubly fed motor, and connected to the grid through a full power converter.

[0083] Step 2 specifically includes:

[0084] Based on the equivalent torque curve signal, the torque curve is calculated by the first four-quadrant frequency converter 4 in the test circuit, and is input into the directly connected permanent magnet synchronous motor 2 or the wound-rotor motor 3 to control the directly connected permanent magnet synchronous motor 2 or the wound-rotor motor 3 to operate and perform the equivalent test;

[0085] The excitation control of the directly connected permanent magnet synchronous motor 2 or winding rotor motor 3 is performed through the second four-quadrant frequency converter 5 in the test circuit, so that the permanent magnet synchronous motor 2 and winding rotor motor 3 can be driven to perform the equivalent test.

[0086] The calculation of the torque curve by the first four-quadrant frequency converter 4 in the test circuit and the input of the torque curve into the directly connected permanent magnet synchronous motor 2 or the wound-rotor motor 3 to control the directly connected permanent magnet synchronous motor 2 or the wound-rotor motor 3 to perform the equivalent test include:

[0087] When the gravity energy storage grid-connected type is direct grid-connected through a synchronous motor or grid-connected through a doubly-fed motor, the torque curve is calculated by the first four-quadrant inverter 4 and input into the permanent magnet synchronous motor 2, so as to control the permanent magnet synchronous motor 2 to operate in a torque control mode to perform the equivalent test;

[0088] When the gravity energy storage grid-connected type is gravity energy storage connected to the grid via a full-power converter, the torque curve is calculated by the first four-quadrant inverter 4 and input into the winding motor 3 to control the operation of the winding motor 3 in the torque control mode, and the torque curve is output to the permanent magnet synchronous motor 2 for the equivalent test.

[0089] The excitation control of the directly connected permanent magnet synchronous motor 2 or the winding rotor motor 3 is performed by the second four-quadrant frequency converter 5 in the test circuit, so that the permanent magnet synchronous motor 2 and the winding rotor motor 3 are subjected to the equivalent test, including:

[0090] When the gravity energy storage grid-connected type is direct grid-connected gravity energy storage through a synchronous motor, a DC excitation is applied to the rotor side of the wound-rotor motor 3 through the second four-quadrant inverter 5 to simulate the characteristics of an electrically excited synchronous motor so that the permanent magnet synchronous motor 2 and the wound-rotor motor 3 are subjected to the equivalent test;

[0091] When the gravity energy storage grid-connected type is gravity energy storage grid-connected through a doubly-fed generator, AC excitation is passed to the rotor side of the winding-rotor motor 3 through the second four-quadrant inverter 5 and vector control is applied to enable the permanent magnet synchronous motor 2 and the winding-rotor motor 3 to perform the equivalent test.

[0092] Step 1 specifically includes:

[0093] Based on the reference power of the gravity energy storage, the host computer 7 calculates the equivalent torque curve expression of the gravity energy storage, and converts the torque curve expression into the torque curve signal and writes it into the first four-quadrant inverter 4.

[0094] The torque curve expression is expressed as follows:

[0095]

[0096] Where, T L is the torque converted from gravitational potential energy, η cis the transmission efficiency, M is the mass of the weight, g is the acceleration of gravity, v is the speed of the weight, θ is the angle between the slope where the gravity energy storage is located and the horizontal plane, ω W is the mechanical angular velocity of the motor, and j is the speed ratio.

[0097] After executing step 2 and before executing step 3, the following steps are also required:

[0098] Obtaining parameters of the torque sensor 1 and the first four-quadrant frequency converter 4 by the host computer 7 during the test;

[0099] The torque curve signal is adjusted by the host computer 7 based on the parameters and sent to the first four-quadrant frequency converter 4, so as to control the first four-quadrant frequency converter 4 to stably output the torque curve equivalent to the reference power of the gravity energy storage;

[0100] The parameters include mechanical torque, mechanical power and motor speed.

[0101] The method proposed in the present invention can flexibly change the topology structure based on existing equipment according to the different types of gravity energy storage grid-connected schemes, so as to be suitable for equivalent tests of different gravity energy storage grid-connected schemes; the present invention converts the reference power of gravity energy storage into the torque of the motor for equivalent tests, which can overcome the limitations of the gravity energy storage test site and truly restore the power characteristics of the gravity energy storage system under different grid-connected topologies during steady-state operation, and conduct equivalent tests of gravity energy storage technologies with different power levels, thereby achieving the purpose of improving the accuracy of power equivalent test data.

[0102] Example 3:

[0103] This embodiment takes slope-type gravity energy storage as an example to introduce the design concept of the device of the present invention and the method of using the device of the present invention. The mechanical system of gravity energy storage is usually composed of a high-level storage yard, a low-level storage yard, a slope track, a transmission device, an energy storage mass block, a load trolley and a crane. The structural diagram of this type of conventional gravity energy storage is shown in the figure below. Figure 4 shown.

[0104] When the gravity energy storage is working in the power generation mode, the crane in the high-rise yard lifts the energy storage mass block and loads it onto the load trolley. The load trolley uses its own power to move to the slope track and is fixed to the slope track through a mechanical device. The torque characteristics generated on the slope track are transmitted to the rotor side of the motor through the transmission device, thereby driving the motor to work in the power generation mode. In this process, the mechanical power generated by the energy storage mass block is expressed as follows:

[0105] P m =nmgvsinθ (1)

[0106] Where, P mis the output power of the mechanical system, n is the number of energy storage mass blocks on the transmission chain, m is the mass of a single energy storage mass block, v is the movement speed of the energy storage mass block (i.e. the speed of the weight), g is the acceleration of gravity, θ is the angle between the gravity energy storage slope and the horizontal plane, and for vertical gravity energy storage, θ = 90°.

[0107] The mechanical power generated by the mechanical system applies driving torque to the generator from the transmission device. The transmission device usually consists of a clutch and a gearbox. One end is connected to the conveyor chain of the load trolley and the other end is connected to the motor. The linear speed of the transmission device is the same at both ends. The speed relationship between the two sides can be expressed as:

[0108] v N =ω L r L =ω w r w (2)

[0109] Where, v N is the rated linear speed of the clutch and gearbox, ω w is the mechanical angular velocity of the transmission motor side (i.e. the mechanical angular velocity of the motor), ω L is the mechanical angular velocity on the motor side, r L and r w They are the transmission shaft radius of the transmission device on the motor side and the transmission shaft radius on the load trolley side respectively.

[0110] From this, the speed ratio j of the transmission device can be expressed as:

[0111]

[0112] When the energy storage mass block is generating electricity, the absorbed power of the transmission mechanism can be expressed as:

[0113] P w =ω w T w (4)

[0114] Where, P w is the mechanical power absorbed by the transmission device, T w is the mechanical torque of the transmission mechanism on the trolley side.

[0115] The mechanical power generated by the energy storage mass block and the absorbed power of the transmission mechanism are balanced in real time, that is, P m =P m ,have:

[0116]

[0117] Since the transmission device will cause power loss during operation, the transmission efficiency η c It can be expressed as:

[0118]

[0119] Where P L is the mechanical power output from the transmission to the motor, T L It is the mechanical torque output by the transmission device to the motor side.

[0120] From formula (6), the mechanical torque of the transmission device on the trolley side converted to the motor side is:

[0121]

[0122] Substituting formula (5) into formula (7), we can obtain the following equation:

[0123]

[0124] At this point, the torque characteristics of gravity energy storage are obtained. Formula (8) is the equivalent torque curve expression of gravity energy storage, which is then converted into the torque curve signal and written into the first four-quadrant inverter 4. After completing the above analysis and calculation, the mechanical device of gravity energy storage can use the host computer, four-quadrant inverter and motor to perform equivalent torque simulation of gravity energy storage. Its equivalent topology is as follows: Figure 5 shown.

[0125] If the power characteristics of gravity energy storage directly connected to the grid through synchronous motors are studied, the test topology is as follows Figure 1 As shown, the second four-quadrant inverter 5 connected to the rotor side of the wound-rotor motor 3 is connected to a DC excitation to simulate an electrically excited synchronous motor. Based on equation (8), and taking into account the rise time and fall time of the torque, the torque curve T is converted to L The first four-quadrant frequency converter 4 is written into the host computer 7 to control the operation of the torque simulation motor in the torque control mode so that the torque simulation motor outputs a given torque curve.

[0126] If the power characteristics of the gravity energy storage system connected to the grid through the doubly fed generator are studied, the test topology is as follows: Figure 1 As shown, the second four-quadrant inverter 5 connected to the rotor side of the wound-rotor motor 3 is connected to AC excitation, and vector control is applied to the doubly fed motor in the second four-quadrant inverter 5. Based on formula (8), and considering the rise time and fall time of the torque, the torque curve T is converted to L The first four-quadrant frequency converter 4 is written into the host computer to control the permanent magnet synchronous motor 2 as a torque simulation motor to operate in the torque control mode, so that the torque simulation motor outputs a given torque curve.

[0127] If the power characteristics of the gravity energy storage system connected to the grid through a full power converter are studied, the test topology is as follows: Figure 2As shown, the permanent magnet synchronous motor 2 is connected to the mains via a full power converter. Based on formula (8), and considering the rise time and fall time of the torque, the torque curve T L By writing into the first four-quadrant frequency converter 4 via the host computer, the winding motor 3, which serves as a torque simulation motor, is controlled to operate in the torque control mode so that the torque simulation motor outputs a given torque curve. Under the input torque curve, the permanent magnet synchronous motor 2 can complete test designs such as speed regulation or forward and reverse rotation, so as to conduct test simulations of power modulation and charging and discharging operating condition switching of the gravity energy storage system connected to the grid via a full-power converter.

[0128] The present invention proposes an equivalent test device for exploring the power characteristics of gravity energy storage, which can realize the power characteristic research of gravity energy storage of different capacities (or different powers) under different grid-connected topologies. The rated capacity of the torque simulation motor can be selected according to the capacity (or power) of the gravity energy storage under study, and the system connection can be flexibly changed according to the grid-connected topology under study. According to the torque characteristics of the established gravity energy storage, the motor is operated in a torque control mode to output the equivalent torque of the gravity energy storage, thereby carrying out the power characteristic research of gravity energy storage under different grid-connected topologies.

[0129] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0130] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0131] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0132] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0133] The above are merely embodiments of the present invention and are not intended 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. An equivalent test device for exploring the power characteristics of gravity energy storage, characterized in that: include: Test circuit and host computer (7); The test circuit is connected to the host computer (7) after being connected to the power grid; The test circuit is built based on the gravity energy storage grid-connected type and is used to output a torque curve corresponding to the equivalent torque curve signal of the gravity energy storage, so as to convert the reference power of the gravity energy storage into the torque of the motor to perform an equivalent test on the power characteristics of the gravity energy storage; The host computer (7) is used to generate the torque curve signal based on the reference power of the gravity energy storage, and write the torque curve signal into the test circuit; and measure the grid-side power of the test circuit in the equivalent test as the result of the equivalent test; The types of gravity energy storage grid connection include direct grid connection through synchronous motors, grid connection through doubly-fed motors, and grid connection through full-power converters.

2. The device according to claim 1, wherein The test circuit comprises: a torque sensor (1), a permanent magnet synchronous motor (2), a wound rotor motor (3), a first four-quadrant frequency converter (4), a second four-quadrant frequency converter (5) and a coupling (6); The permanent magnet synchronous motor (2), the torque sensor (1) and the wound-rotor motor (3) are connected in sequence via a coupling (6); When the gravity energy storage grid-connected type is gravity energy storage directly connected to the grid through a synchronous motor or connected to the grid through a doubly fed motor, the permanent magnet synchronous motor (2) is connected to the first four-quadrant frequency converter (4), the rotor side of the winding-rotor motor (3) is connected to the second four-quadrant frequency converter (5), and the winding-rotor motor (3) is also connected to the power grid; when the gravity energy storage grid-connected type is gravity energy storage connected to the grid through a full-power converter, the permanent magnet synchronous motor (2) is connected to the second four-quadrant frequency converter (5), the winding-rotor motor (3) is connected to the first four-quadrant frequency converter (4), and the rotor side of the winding-rotor motor (3) is short-circuited; The first four-quadrant frequency converter (4) and the second four-quadrant frequency converter (5) are both connected to the power grid; the first four-quadrant frequency converter (4) is connected to the host computer (7) and is used to calculate the torque curve based on the equivalent torque curve signal and input it into the directly connected permanent magnet synchronous motor (2) or the winding-type motor (3), and perform the equivalent test by controlling the operation of the directly connected permanent magnet synchronous motor (2) or the winding-type motor (3); the second four-quadrant frequency converter (5) is used to perform excitation control on the directly connected permanent magnet synchronous motor (2) or the winding-type motor (3), so that the permanent magnet synchronous motor (2) and the winding-type motor (3) are driven to perform the equivalent test; the grid-connected side of the second four-quadrant frequency converter (5) is also connected to the host computer (7); The torque sensor (1) is connected to the host computer (7); The capacities of the permanent magnet synchronous motor (2) and the wound rotor motor (3) are determined based on the reference power of the gravity energy storage.

3. The device according to claim 2, wherein The first four-quadrant frequency converter (4) is specifically used for: calculating the torque curve based on the equivalent torque curve signal; When the gravity energy storage grid connection type is direct grid connection via a synchronous motor or grid connection via a doubly-fed motor, the torque curve is input into the permanent magnet synchronous motor (2) to control the permanent magnet synchronous motor (2) to operate in a torque control mode to perform the equivalent test; When the gravity energy storage grid-connected type is gravity energy storage grid-connected via a full-power converter, the torque curve is input into the winding motor (3) to control the winding motor (3) to operate in a torque control mode, and the torque curve is output to the permanent magnet synchronous motor (2) to perform the equivalent test.

4. The device according to claim 2, wherein The second four-quadrant frequency converter (5) is specifically used for: When the gravity energy storage grid connection type is direct grid connection via a synchronous motor, direct current excitation is applied to the rotor side of the wound-rotor motor (3) to simulate the characteristics of an electrically excited synchronous motor so that the permanent magnet synchronous motor (2) and the wound-rotor motor (3) are subjected to the equivalent test; When the gravity energy storage grid connection type is gravity energy storage grid connection through a doubly fed generator, AC excitation is applied to the rotor side of the winding-rotor motor (3) and vector control is applied to enable the permanent magnet synchronous motor (2) and the winding-rotor motor (3) to perform the equivalent test.

5. The device according to claim 2, wherein The host computer (7) is specifically used for: An equivalent torque curve expression of the gravity energy storage is calculated based on the reference power of the gravity energy storage, and the torque curve expression is converted into the torque curve signal and written into the first four-quadrant frequency converter (4); and is used to obtain the grid-side power of the grid-connected side of the second four-quadrant frequency converter (5) as the result of the equivalent test.

6. The device according to claim 5, characterized in that The torque curve expression is expressed as follows: Where, T L is the torque converted from gravitational potential energy, η c is the transmission efficiency, M is the mass of the weight, g is the acceleration of gravity, v is the speed of the weight, θ is the angle between the slope where the gravity energy storage is located and the horizontal plane, ω w is the mechanical angular velocity of the motor, and j is the speed ratio.

7. The device according to claim 5, characterized in that The host computer (7) is also used for: Obtaining parameters of the torque sensor (1) and the first four-quadrant frequency converter (4) in the equivalent test; The torque curve signal is adjusted based on the parameter and sent to the first four-quadrant frequency converter (4) to control the first four-quadrant frequency converter (4) to stably output the torque curve equivalent to the reference power of the gravity energy storage; The parameters include mechanical torque, mechanical power and motor speed.

8. An equivalent test method for exploring the power characteristics of gravity energy storage, characterized in that: The method uses an equivalent test device for exploring the power characteristics of gravity energy storage as described in any one of claims 1 to 7 to perform an equivalent test of the power characteristics of gravity energy storage, and the method includes: Based on the reference power of the gravity energy storage, an equivalent torque curve signal of the gravity energy storage is generated by a host computer (7), and the torque curve signal is written into the test circuit; Outputting a torque curve corresponding to the torque curve signal through the test circuit to equivalently convert the reference power of the gravity energy storage into the torque of the motor to perform an equivalent test on the power characteristics of the gravity energy storage; Measuring the grid-side power of the test circuit by the host computer (7) in the equivalent test as the result of the equivalent test; Among them, the test circuit is built based on the gravity energy storage grid-connected type; the gravity energy storage grid-connected type includes gravity energy storage directly connected to the grid through a synchronous motor, connected to the grid through a doubly fed motor, and connected to the grid through a full power converter.

9. The method according to claim 8, wherein The test circuit outputs a torque curve corresponding to the torque curve signal to convert the reference power of the gravity energy storage into the torque of the motor to perform an equivalent test on the power characteristics of the gravity energy storage, including: Based on the equivalent torque curve signal, the torque curve is calculated by a first four-quadrant frequency converter (4) in the test circuit, and is input into the directly connected permanent magnet synchronous motor (2) or the wound-rotor motor (3) to control the directly connected permanent magnet synchronous motor (2) or the wound-rotor motor (3) to operate and perform the equivalent test; The excitation control of the directly connected permanent magnet synchronous motor (2) or the wound-rotor motor (3) is performed through the second four-quadrant frequency converter (5) in the test circuit, so that the permanent magnet synchronous motor (2) and the wound-rotor motor (3) are subjected to the equivalent test.

10. The method according to claim 9, wherein The torque curve is calculated by the first four-quadrant frequency converter (4) in the test circuit, and is input into the directly connected permanent magnet synchronous motor (2) or the wound-rotor motor (3) to control the directly connected permanent magnet synchronous motor (2) or the wound-rotor motor (3) to run and perform the equivalent test, comprising: When the gravity energy storage grid connection type is direct grid connection via a synchronous motor or grid connection via a doubly-fed motor, the torque curve is calculated by the first four-quadrant frequency converter (4) and inputted into the permanent magnet synchronous motor (2), so as to control the permanent magnet synchronous motor (2) to operate in a torque control mode and perform the equivalent test; When the gravity energy storage grid-connected type is gravity energy storage grid-connected via a full-power converter, the torque curve is calculated by the first four-quadrant frequency converter (4) and input into the winding-rotor motor (3) to control the winding-rotor motor (3) to operate in a torque control mode, and the torque curve is output to the permanent magnet synchronous motor (2) to perform the equivalent test.

11. The method according to claim 9, wherein The method of controlling the excitation of the directly connected permanent magnet synchronous motor (2) or the wound-rotor motor (3) by the second four-quadrant frequency converter (5) in the test circuit so as to conduct the equivalent test on the permanent magnet synchronous motor (2) and the wound-rotor motor (3) comprises: When the gravity energy storage grid connection type is direct grid connection via a synchronous motor, direct current excitation is applied to the rotor side of the wound-rotor motor (3) via the second four-quadrant frequency converter (5) to simulate the characteristics of an electrically excited synchronous motor so that the permanent magnet synchronous motor (2) and the wound-rotor motor (3) are subjected to the equivalent test; When the gravity energy storage grid-connected type is gravity energy storage grid-connected through a doubly-fed generator, AC excitation is applied to the rotor side of the wound-rotor motor (3) through the second four-quadrant frequency converter (5) and vector control is applied, so that the permanent magnet synchronous motor (2) and the wound-rotor motor (3) are towed to perform the equivalent test.

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