An AC magnetohydrodynamic propulsion system based on series winding drive

Abstract

The present invention provides an AC magnetohydrodynamic propulsion system based on series winding drive, which provides a new technology for ship magnetohydrodynamic propulsion. By adopting a series winding drive mode, the system integration is improved, and the voltage utilization rate is improved compared with the traditional three-phase full-bridge drive mode; compared with the "H-bridge" drive mode, the demand for controllable switching devices is reduced, and the system cost and complexity are reduced; compared with the traditional propeller-shaft propulsion mode, the vibration noise of the propeller during operation is reduced, and the concealment is improved; the existing propeller-shaft drive mode solves the problems of large vibration noise and speed limit, as well as the problem that the traditional drive device requires more switching devices and their auxiliary circuits.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetofluid propulsion, and in particular relates to an AC magnetofluid propulsion system based on series winding drive. Background Art

[0002] The current propulsion method for ships is mainly propeller-shaft propulsion, which generates large vibration noise and is prone to cavitation at high speeds, which can easily cause propeller blade damage and other accidents. Especially for underwater vehicles, the propeller-shaft propulsion method is not conducive to improving their concealment and also limits the increase in speed.

[0003] Magnetohydrodynamic propulsion is a new type of propulsion method that uses the interaction between the electric current and the magnetic field in the seawater to make the seawater move and generate propulsion. A magnetic field is established in the channel using magnets, and power is supplied to the seawater through electrodes. When current passes through the seawater, the magnetic field generates an electromagnetic force on the current-carrying seawater, and the seawater moves under this electromagnetic force. The generated reaction force, i.e., the propulsion force, drives the ship to move. The magnetic field in the channel is established by the winding coil. According to the form of the winding current, the magnetohydrodynamic propulsion method can be divided into DC magnetohydrodynamic propulsion and AC magnetohydrodynamic propulsion. AC magnetohydrodynamic propulsion does not require the use of electrodes, thereby avoiding the electrolysis of seawater and electrode corrosion caused by the presence of electrodes, and also greatly reduces the noise and bubble problems generated by the movement of the ship's magnetohydrodynamic propulsor. For AC magnetohydrodynamic propulsors, the drive and control of their winding current is of vital importance for propulsion control and ship speed control. The AC magnetohydrodynamic propulsion system generates three-phase current in the windings. The commonly used driving structure is the three-phase full-bridge structure, which has the disadvantage of relatively low voltage utilization. Although using an "H full-bridge" to drive each winding can improve voltage utilization, it requires more switching devices and their ancillary circuits, which is not conducive to reducing weight and volume, and is not conducive to further improving endurance. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an AC magnetohydrodynamic propulsion system based on series winding drive, which is used to solve the problems of large vibration and noise caused by the existing propeller-shaft system drive method, limiting the increase in speed, and the problem that the traditional drive device requires more switching devices and their associated circuits.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: an AC magnetohydrodynamic propulsion system based on series winding drive, comprising a speed control device, a series winding drive device and a magnetohydrodynamic propulsion device connected in sequence; the speed control device is used to receive a preset or upper computer speed command RefH, a speed measurement value MesH collected by a speed sensor, a fluid flow rate Mesh collected by a flow rate sensor of the magnetohydrodynamic propulsion device, and a three-phase current measurement value Ia, Ib, Ic collected by a three-phase current sensor of the series winding drive device, and generate a corresponding gate extreme control signal to control the switch device of the series winding drive device to turn on and off; the series winding drive device is used to provide AC current for the winding of the magnetohydrodynamic propulsion device; the series winding drive device includes a DC power supply Vdc, a controllable switch device Si, a unidirectional conduction device Di and three-phase current sensors Ma, Mb, Mc, i=1~ 8; the controllable switch device Si is connected in reverse parallel with the unidirectional conducting device Di: the output end of the controllable switch device Si is connected to the input end of the unidirectional conducting device Di, and the input end of the controllable switch device Si is connected to the output end of the unidirectional conducting device Di; when i is an odd number, the input end of the controllable switch device Si and the output end of the unidirectional conducting device Di are connected to the positive pole of the DC power supply Vdc; when i is an even number, the output end of the controllable switch device Si and the input end of the unidirectional conducting device Di are connected to the negative pole of the DC power supply Vdc; the midpoint of the bridge arm of the series winding drive device is connected to the corresponding winding of the magnetohydrodynamic propulsion device, and the corresponding three-phase current sensors Ma, Mb, Mc are used to measure and output the three-phase current measurement values ​​Ia, Ib, Ic respectively; the magnetohydrodynamic propulsion device includes three-phase windings La, Lb, Lc, as well as a fluid channel, an inlet guide vane, an outlet guide vane, a flow rate sensor, an electrolyte adder and an electrolyte recoverer.

[0006] According to the above scheme, the speed control device includes a speed control module, a current control module and a modulation signal generating module which are connected in sequence; the speed control module is used to perform calculations according to the speed instruction RefH, the speed measurement value MesH, the fluid flow rate Mesh and the control algorithm, and output the three-phase current control instructions RIa, RIb, RIc respectively; the current control module is used to perform calculations according to the three-phase current control instructions RIa, RIb, RIc and the three-phase current measurement values ​​Ia, Ib, Ic and the control algorithm, and output the duty cycle di of the controllable switch device Si of the series winding drive device; the modulation signal generating module is used to generate the corresponding gate terminal control signal Pi according to the duty cycle di, so as to control the controllable switch device Si of the series winding drive device to be turned on and off.

[0007] According to the above scheme, the unidirectional conducting device Di is unidirectionally conducted from the corresponding input end to the output end; the controllable switch device Si is conducted from the corresponding input end to the output end, and is turned on and off by the corresponding gate pole, and the gate pole control signal comes from the speed control device; the gate pole control signal of the controllable switch device Si is a pulse modulation signal with adjustable duty cycle, and the controllable switch device Si changes the conduction time by changing its gate control signal; the conduction time of the controllable switch device Si is the duty cycle of the pulse width modulation signal multiplied by the switching cycle length.

[0008] According to the above scheme, a diode is used as the unidirectional conducting device; and an insulated gate bipolar transistor is used as the controllable switch device.

[0009] According to the above scheme, the connection point between the output end of the controllable switch device S1 and the input end of the controllable switch device S2 is set as the midpoint of the bridge arm No. 1, and the midpoint of the bridge arm No. 1 is connected to the first end La+ of the winding La of the magnetic fluid propulsion device; the current sensor Ma is used to measure the current of the winding La to obtain the current measurement value Ia; the connection point between the output end of the controllable switch device S3 and the input end of the controllable switch device S4 is set as the midpoint of the bridge arm No. 2, and the midpoint of the bridge arm No. 2 is connected to the second end La- of the winding La of the magnetic fluid propulsion device and the first end Lb of the winding Lb+; the current sensor Mb is used to measure the current of the winding La. The current of group Lb is obtained to obtain the current measurement value Ib; the connection point between the output end of the controllable switch device S5 and the input end of the controllable switch device S6 is set as the midpoint of bridge arm No. 3, and the midpoint of bridge arm No. 3 is connected to the second end of winding Lb of the magnetohydrodynamic propulsion device, i.e. Lb-, and the first end of winding Lc, i.e. Lc+; the current sensor Mc is used to measure the current of winding Lc to obtain the current measurement value Ic; the connection point between the output end of the controllable switch device S7 and the input end of the controllable switch device S8 is set as the midpoint of bridge arm No. 4, and the midpoint of bridge arm No. 4 is connected to the second end of winding Lc of the magnetohydrodynamic propulsion device, i.e. Lc-.

[0010] According to the above scheme, the winding material is superconducting material; the winding arrangement adopts a cylindrical internal magnetic type; each phase winding includes an inner cylinder part and an outer cylinder part, and at the same axial position of the cylinder, the winding current direction of the inner cylinder part is opposite to the winding current direction of the outer cylinder part; the inlet end of the fluid channel is used to input the fluid, and the outlet end of the fluid channel is used to output the fluid; the inlet guide vane and the outlet guide vane are respectively arranged at the inlet end and the outlet end of the fluid channel, respectively used to adjust the flow direction when the fluid enters and flows out of the fluid channel, and reduce the fluid resistance; the flow rate sensor is arranged in the fluid channel, used to measure the flow rate of the fluid in the fluid channel, and send the flow rate measurement value to the speed control device; the electrolyte adder is arranged at the inlet end of the fluid channel, used to add electrolyte to the fluid entering the fluid channel, used to enhance the conductivity of the fluid when the underwater vehicle travels in a freshwater area or a low-salinity seawater area; the electrolyte recovery device is arranged at the outlet end of the fluid channel, used to recover electrolyte from the fluid leaving the fluid channel, to avoid the contamination of the original water area by the outlet fluid due to the action of the electrolyte adder, and to improve the concealment.

[0011] The beneficial effects of the present invention are:

[0012] 1. The AC magnetohydrodynamic propulsion system based on series winding drive of the present invention provides a new technology for the ship magnetohydrodynamic propulsion method. By adopting the series winding drive method, the system integration is improved, the demand for controllable switching devices in the drive method is reduced, the system cost, volume and weight are reduced, and the problems of large vibration and noise caused by the existing propeller-shaft system drive method and the limitation of speed increase are solved, as well as the problem that the traditional drive device requires more switching devices and their auxiliary circuits.

[0013] 2. Compared with the traditional three-phase full-bridge driving method, the present invention improves the voltage utilization rate.

[0014] 3. Compared with the "H-bridge" driving method, the present invention saves the demand for controllable switching devices and reduces system cost and complexity.

[0015] 4. Compared with the traditional propeller-shaft propulsion method, the present invention reduces the vibration noise of the propeller during operation and improves concealment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a system according to an embodiment of the present invention.

[0017] Figure 2 2 is a circuit structure and current control method diagram of an embodiment of the present invention.

[0018] Figure 3 Schematic diagram of a magnetohydrodynamic propulsion device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0020] See also Figure 1 , an embodiment of the present invention includes a series winding drive device, a speed control device and a magnetohydrodynamic propulsion device.

[0021] 1. Series winding drive device

[0022] See also Figure 2 The series winding driving device is used to provide AC current for the winding of the magnetohydrodynamic propulsion device, including a DC power supply Vdc, 8 controllable switch devices S1, S2, S3, S4, S5, S6, S7, S8, 8 unidirectional conductive devices D1, D2, D3, D4, D5, D6, D7, D8, and 3 current sensors Ma, Mb, Mc;

[0023] Among them, the input ends of the controllable switch devices S1, S3, S5, and S7 are connected to the positive electrode of the DC power supply Vdc, the output ends of the controllable switch devices S2, S4, S6, and S8 are connected to the negative electrode of the DC power supply Vdc, the output ends of the unidirectional conducting devices D1, D3, D5, and D7 are connected to the positive electrode of the DC power supply Vdc, and the input ends of the unidirectional conducting devices D2, D4, D6, and D8 are connected to the negative electrode of the DC power supply Vdc;

[0024] Taking S1 as an example, the input end of S1 is the terminal indicated by label ①, the output end of S1 is the terminal indicated by label ②, and the gate end of S1 is the terminal indicated by label ③;

[0025] Taking D1 as an example, the input end of D1 is the terminal indicated by label ④, and the output end of D1 is the terminal indicated by label ⑤;

[0026] The controllable switch device Sk is connected in reverse parallel with the unidirectional conducting device Dk: the output end of Sk is connected to the input end of Dk, and the input end of Sk is connected to the output end of Dk, where k=1-8;

[0027] The midpoints of the bridge arms of the series winding drive device are connected to the corresponding windings of the magnetohydrodynamic propulsion device, and output three-phase current, including:

[0028] The output end of the controllable switch device S1 is connected to the input end of the controllable switch device S2, and the connection point is called the midpoint of the bridge arm No. 1. The midpoint of the bridge arm No. 1 is connected to the first end (labeled as La+) of the winding La of the magnetohydrodynamic propulsion device. The current of the winding La is Ia, and the current sensor Ma can measure Ia and obtain the measured value;

[0029] The output end of the controllable switch device S3 is connected to the input end of the controllable switch device S4, and the connection point is called the midpoint of the bridge arm No. 2. The midpoint of the bridge arm No. 2 is connected to the first end (labeled as Lb+) of the winding Lb of the magnetohydrodynamic propulsion device and the second end (labeled as La-) of the winding La. The current of the winding Lb is Ib, and the current sensor Mb can measure Ib and obtain the measured value;

[0030] The output end of the controllable switch device S5 is connected to the input end of the controllable switch device S6, and the connection point is called the midpoint of the bridge arm No. 3. The midpoint of the bridge arm No. 3 is connected to the second end (labeled as Lb-) of the winding Lb of the magnetohydrodynamic propulsion device and the first end (labeled as Lc+) of the winding Lc. The current of the winding Lc is Ic, and the current sensor Mc can measure Ic and obtain the measured value;

[0031] The output end of the controllable switch device S7 is connected to the input end of the controllable switch device S8, and the connection point is called the middle point of the bridge arm No. 4, and the middle point of the bridge arm No. 4 is connected to the second end of the winding Lc of the magnetic fluid propulsion device;

[0032] The unidirectional conducting devices D1, D2, D3, D4, D5, D6, D7, and D8 all conduct unidirectionally from the corresponding input end to the output end;

[0033] In this embodiment, the unidirectional conducting devices are all diodes;

[0034] The controllable switch devices S1, S2, S3, S4, S5, S6, S7, and S8 are all turned on and off from the corresponding input end to the output end, and the corresponding gate extremes are used to control the on and off, and the control signals of each gate extreme come from the speed control device;

[0035] In this embodiment, each controllable switch device is an insulated gate bipolar transistor;

[0036] The gate control signals of each controllable switch device are pulse modulation signals with adjustable duty cycle. Each controllable switch device changes its on-time by changing its gate control signal. The on-time of each controllable switch device is the duty cycle of each pulse width modulation signal multiplied by the switching cycle length.

[0037] 2. Speed ​​Control Device

[0038] The speed control device includes a speed control module, a current control module and a modulation signal generation module;

[0039] The speed control device receives the speed command RefH set manually or by its superior system, receives the speed measurement value MesH collected by the speed sensor, receives the fluid flow rate Mesh collected by the flow rate sensor in the magnetohydrodynamic propulsion device, and receives the measurement values ​​Ia, Ib, and Ic of the current sensor of the series winding drive device;

[0040] The speed control module calculates according to the speed command RefH, the speed measurement value MesH, the fluid flow rate Mesh and the control algorithm to obtain the current control commands RIa, RIb and RIc;

[0041] The current control module calculates the current control instructions RIa, RIb, RIc and the current measurement values ​​Ia, Ib, Ic and the control algorithm to obtain the duty cycle di of the switching device Si (where i=1-8);

[0042] The modulation signal generation module generates a corresponding gate terminal control signal Pi (i=1-8) according to the duty cycle di (i=1-8), which is used to turn on and off the switch device of the series winding driving device.

[0043] 3. Magnetohydrodynamic propulsion device

[0044] See also Figure 3 , the magnetohydrodynamic propulsion device includes three windings La, Lb, Lc, as well as a fluid channel, an inlet guide vane, an outlet guide vane, a flow rate sensor, an electrolyte adder and an electrolyte recoverer;

[0045] The winding material is made of superconducting material; the winding arrangement adopts cylindrical internal magnetic type;

[0046] Each phase winding includes an inner cylinder part and an outer cylinder part. At the same axial position of the cylinder, the current direction of the inner cylinder part winding is opposite to that of the outer cylinder part winding.

[0047] The fluid enters the fluid channel from the inlet end and leaves the fluid channel from the outlet end;

[0048] The inlet guide vane is used to adjust the flow direction of the fluid when it enters the flow channel to reduce the fluid resistance;

[0049] The outlet guide vane is used to adjust the flow direction of the fluid when it flows out of the flow channel to reduce the fluid resistance;

[0050] The flow velocity sensor is used to measure the flow velocity of the fluid in the flow channel and input the flow velocity measurement value into the speed control device;

[0051] The electrolyte adder is used to add electrolyte to the fluid entering the fluid channel, so as to enhance the conductivity of the fluid when the underwater vehicle travels in a freshwater area or a low-salinity seawater area;

[0052] The electrolyte recoverer is used to recover electrolyte from the fluid leaving the fluid channel, and is used to avoid the contamination of the original water area by the outlet fluid when the electrolyte adder is in action, and to improve concealment.

[0053] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. An AC magnetic fluid propulsion system based on series winding drive, characterized in that: It includes a speed control device, a series winding drive device and a magnetohydrodynamic propulsion device connected in sequence; The speed control device is used to receive the preset or upper computer speed command RefH, the speed measurement value MesH collected by the speed sensor, the fluid flow rate Mesh collected by the flow rate sensor of the magnetohydrodynamic propulsion device, and the three-phase current measurement values ​​Ia, Ib, Ic collected by the three-phase current sensor of the series winding drive device, and generate corresponding gate extreme control signals to control the switch device of the series winding drive device to turn on and off; The series winding driving device is used to provide AC current for the winding of the magnetohydrodynamic propulsion device; the series winding driving device includes a DC power supply Vdc, a controllable switch device Si, a unidirectional conductive device Di and three-phase current sensors Ma, Mb, Mc, i=1-8; the controllable switch device Si is connected in reverse parallel with the unidirectional conductive device Di: the output end of the controllable switch device Si is connected to the input end of the unidirectional conductive device Di, and the input end of the controllable switch device Si is connected to the output end of the unidirectional conductive device Di; when i is an odd number, the input end of the controllable switch device Si and the output end of the unidirectional conductive device Di are connected to the positive electrode of the DC power supply Vdc; when i is an even number, the output end of the controllable switch device Si and the input end of the unidirectional conductive device Di are connected to the negative electrode of the DC power supply Vdc; The midpoint of the bridge arm of the series winding drive device is connected to the corresponding winding of the magnetic fluid propulsion device, and the corresponding three-phase current sensors Ma, Mb, Mc are used to measure and output the three-phase current measurement values ​​Ia, Ib, Ic respectively; The magnetohydrodynamic propulsion device includes three-phase windings La, Lb, and Lc, as well as a fluid channel, an inlet guide vane, an outlet guide vane, a flow rate sensor, an electrolyte adder, and an electrolyte recoverer.

2. The AC magnetic fluid propulsion system based on series winding drive according to claim 1 is characterized in that: The speed control device comprises a speed control module, a current control module and a modulation signal generation module connected in sequence; The speed control module is used to perform calculations based on the speed command RefH, the speed measurement value MesH, the fluid flow rate Mesh and the control algorithm, and output three-phase current control commands RIa, RIb and RIc respectively; The current control module is used to calculate the duty cycle di of the controllable switch device Si of the series winding drive device according to the three-phase current control instructions RIa, RIb, RIc and the three-phase current measurement values ​​Ia, Ib, Ic and the control algorithm; The modulation signal generation module is used to generate a corresponding gate terminal control signal Pi according to the duty cycle di, so as to control the controllable switch device Si of the series winding driving device to be turned on and off.

3. The AC magnetic fluid propulsion system based on series winding drive according to claim 1 is characterized in that: The unidirectional conducting device Di conducts unidirectionally from the corresponding input end to the output end; the controllable switch device Si conducts from the corresponding input end to the output end, and is turned on and off by the corresponding gate extreme point control signal from the speed control device; The gate control signals of the controllable switch device Si are all pulse modulation signals with adjustable duty cycle. The controllable switch device Si changes its conduction time by changing its gate control signal; the conduction time of the controllable switch device Si is the duty cycle of the pulse width modulation signal multiplied by the switching cycle length.

4. The AC magnetic fluid propulsion system based on series winding drive according to claim 1 is characterized in that: The unidirectional conducting device adopts a diode; the controllable switch device adopts an insulated gate bipolar transistor.

5. The AC magnetic fluid propulsion system based on series winding drive according to claim 1 is characterized in that: Assume that the connection point between the output end of the controllable switch device S1 and the input end of the controllable switch device S2 is the midpoint of bridge arm 1, and the midpoint of bridge arm 1 is connected to the first end La+ of the winding La of the magnetic fluid propulsion device; the current sensor Ma is used to measure the current of the winding La to obtain the current measurement value Ia; Assume that the connection point between the output end of the controllable switch device S3 and the input end of the controllable switch device S4 is the midpoint of bridge arm No. 2, and the midpoint of bridge arm No. 2 is connected to the second end of winding La of the magnetohydrodynamic propulsion device, namely La-, and the first end of winding Lb, namely Lb+; the current sensor Mb is used to measure the current of winding Lb to obtain the current measurement value Ib; the connection point between the output end of the controllable switch device S5 and the input end of the controllable switch device S6 is the midpoint of bridge arm No. 3, and the midpoint of bridge arm No. 3 is connected to the second end of winding Lb of the magnetohydrodynamic propulsion device, namely Lb-, and the first end of winding Lc, namely Lc+; the current sensor Mc is used to measure the current of winding Lc to obtain the current measurement value Ic; the connection point between the output end of the controllable switch device S7 and the input end of the controllable switch device S8 is the midpoint of bridge arm No. 4, and the midpoint of bridge arm No. 4 is connected to the second end of winding Lc of the magnetohydrodynamic propulsion device, namely Lc-.

6. The AC magnetic fluid propulsion system based on series winding drive according to claim 1 is characterized in that: The winding material is superconducting material; the winding arrangement adopts cylindrical internal magnetic type; Each phase winding includes an inner cylinder part and an outer cylinder part. At the same position in the axial direction of the cylinder, the winding current direction of the inner cylinder part is opposite to the winding current direction of the outer cylinder part. The inlet end of the fluid channel is used to input the fluid, and the outlet end of the fluid channel is used to output the fluid; the inlet guide vane and the outlet guide vane are respectively arranged at the inlet end and the outlet end of the fluid channel, and are respectively used to adjust the flow direction when the fluid enters and flows out of the fluid channel, thereby reducing the fluid resistance; The flow velocity sensor is arranged in the fluid channel, and is used to measure the flow velocity of the fluid in the fluid channel, and send the flow velocity measurement value to the speed control device; The electrolyte adder is arranged at the inlet end of the fluid channel, and is used to add electrolyte to the fluid entering the fluid channel, so as to enhance the conductivity of the fluid when the underwater vehicle travels in a fresh water area or a low-salinity seawater area; The electrolyte recovery device is arranged at the outlet end of the fluid channel, and is used to recover electrolyte from the fluid leaving the fluid channel, so as to avoid the contamination of the original water area by the outlet fluid due to the action of the electrolyte additive, and to improve concealment.

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