Transmission system

Abstract

The utility model discloses a transmission system. The transmission system comprises a motor; one end of the speed regulator is connected with the motor, and the other end is disconnected with the load before the motor is started and connected with the load after the motor is started; the control system is used for controlling the operation states of the motor and the speed regulator; before the motor is started, the control system controls the motor to be powered off and controls the speed regulator to be powered on, so that the speed regulator drives the motor to rotate, and when the motor reaches the rated rotating speed, the control system controls the speed regulator to be powered off and simultaneously controls the motor to be powered on. According to the utility model, the starting impact can be reduced, the influence on the motor and a power grid is reduced, the current demand during starting is reduced, the capacity of a power grid system is reduced, smooth starting can be realized, the motor is driven to rotate through the speed regulator, the motor generates no-load counter electromotive force, and the motor can be started more stably when electrified; the reliability and the stability of motor starting are improved, and the mechanical stress during motor starting is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to electrical engineering technical field, concretely relates to a transmission system. BACKGROUND

[0002] At present, the motor often faces problems of large starting impact and excessive starting capacity during starting process, which leads to increased loss of the motor and its driving system and reduced reliability. The existing motor starting scheme fails to effectively solve these problems, which limits the motor starting efficiency and performance under different working conditions.

[0003] Asynchronous starting and synchronous running is that the motor is directly connected to the power supply for starting. The motor of this starting mode needs to increase asynchronous starting squirrel cage, increase the amount of magnetic steel and the size of the iron core of the permanent magnet rotor, etc. This starting mode has the following shortcomings: first, the starting capacity requirement is large, generally 9-10 times of the rated capacity, and the capacity of load starting may reach 11-13 times, which causes impact on the power grid; second, the starting impact is large, and the starting time is short, because the high starting current may exceed the rated bearing capacity of the motor, which leads to its inapplicability to high-power motors. SUMMARY

[0004] Therefore, the utility model wants to solve the technical problem in overcoming the defects of large starting capacity and large starting impact of the current motor starting mode, so as to provide a transmission system.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the utility model is:

[0006] A transmission system, comprising:

[0007] A motor;

[0008] A speed regulator, one end of the speed regulator is connected with the motor, and the other end of the speed regulator is disconnected with the load before the motor starts and connected with the load after the motor starts;

[0009] A control system, the control system is used for controlling the running state of the motor and the speed regulator; before the motor starts, the control system controls the motor to be powered off, the control system controls the speed regulator to be powered on, so that the speed regulator drives the motor to rotate, and when the motor reaches its rated speed, the control system controls the speed regulator to be powered off and simultaneously controls the motor to be powered on.

[0010] Further optimization technical scheme, the motor and the power supply are connected through a first line, a first switch is arranged on the first line, and the control system is used for controlling the on-off of the first switch to control the connection between the motor and the power supply.

[0011] Further optimization technical scheme, the control system comprises:

[0012] An inverter, one end of which is electrically connected with the power supply, and the other end of which is electrically connected with the speed regulator.

[0013] Further optimization of the technical scheme, the inverter is a four-quadrant inverter, the four-quadrant inverter is connected with a second line, a third line, a fourth line and a fifth line; one end of the fifth line is connected with the power supply, and the other end of the fifth line is connected with the input end of the four-quadrant inverter; one end of the second line is connected with the output end of the four-quadrant inverter, and the other end of the second line is connected with the input end of the speed regulator, and a second switch is arranged on the second line; one end of the third line is connected with the power supply, and the other end of the third line is connected with the second line between the output end of the four-quadrant inverter and the second switch, and a third switch is arranged on the third line; one end of the fourth line is connected with the fifth line, and the other end of the fourth line is connected with the second line between the second switch and the speed regulator, and a fourth switch is arranged on the fourth line.

[0014] The four-quadrant inverter has a forward use state and a reverse use state; before the motor starts, when it is needed to make the four-quadrant inverter in the forward use state, the second switch is closed, the speed regulator is powered on, when the motor driven by the speed regulator reaches the rated speed of the motor, the first switch is closed, and the motor is powered on; after the motor starts, when it is needed to make the four-quadrant inverter in the reverse use state, the second switch is opened, the first switch, the third switch and the fourth switch are closed, and the slip power generated by the speed regulator is converted into electric energy by the four-quadrant inverter and fed back to the power supply.

[0015] Further optimization of the technical scheme, the inverter is a four-quadrant inverter, the four-quadrant inverter is connected with a second line, a third line, a fourth line and a fifth line; one end of the fifth line is connected with the power supply, and the other end of the fifth line is connected with the input end of the four-quadrant inverter; one end of the second line is connected with the output end of the four-quadrant inverter, and the other end of the second line is connected with the input end of the speed regulator, and a second switch is arranged on the second line; one end of the third line is connected with the power supply, and the other end of the third line is connected with the second line between the output end of the four-quadrant inverter and the second switch, and a third switch is arranged on the third line; one end of the fourth line is connected with the fifth line, and the other end of the fourth line is connected with the second line between the second switch and the speed regulator, and a fourth switch is arranged on the fourth line.

[0016] Further optimization of the technical scheme, the control system further comprises:

[0017] A three-phase rectifier circuit, which is arranged between the power supply and the four-quadrant inverter.

[0018] The power supply is a power frequency power supply; before the motor starts, the three-phase rectifier circuit converts the three-phase alternating current of the power supply into direct current, and then converts the direct current into alternating current through the four-quadrant inverter to drive the speed regulator to rotate; when the motor is running at a non-full load, the slip power generated by the speed regulator is converted into direct current by the four-quadrant inverter, and then the direct current is converted into alternating current by the three-phase rectifier circuit and fed back to the power supply.

[0019] Further optimization of the technical scheme, the control system further comprises:

[0020] The switch power supply circuit is used for controlling the voltage and current outputted by the inverter, so that the motor starts with low torque at the initial stage and quickly responds to the load change after the motor starts.

[0021] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0022] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0023] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0024] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0025] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0026] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0027] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0028] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0029] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0030] The switch power supply circuit is a PWM circuit or a BOOST circuit.

[0031] After the motor is started, the speed regulator is connected with the load through the control system.

[0032] Further optimization technical scheme, before the motor is started, in the process of rotating the motor driven by the speed regulator, the state of the motor is monitored in real time, the voltage and current output by the inverter are controlled through the switching power supply circuit, and then the voltage and current of the winding rotor of the speed regulator are controlled, so that the rotating speed of the motor is controlled.

[0033] Further optimization technical scheme, after the speed regulator is connected with the load through the control system, the voltage and current of the winding rotor of the speed regulator are adjusted based on the size of the load or the production needs, so that the rotating speed and torque of the motor are adjusted.

[0034] The utility model technical scheme has the following advantages:

[0035] 1. The transmission system provided by the utility model can reduce the starting impact and reduce the influence on the motor and the power grid: the motor is first smoothly driven to rotate by the speed regulator, and can be switched to the state of directly supplying power to the motor after the motor reaches the rated rotating speed. Since the motor has a certain rotating speed when starting, the motor rotor will generate a back electromotive force when rotating in the magnetic field, and the existence of the back electromotive force helps to reduce the starting current, thereby avoiding the starting impact on the power grid when the motor is directly connected to the power source for starting.

[0036] The transmission system provided by the utility model reduces the current demand during starting and reduces the capacity of the power grid system: since the speed regulator provides part of the torque required by the motor in the initial stage, it actually replaces part of the starting power demand of the motor. Before the motor reaches a stable state, it has obtained a certain rotating speed and torque through the power supply of the speed regulator, so that the starting capacity demand of the power source is also reduced.

[0037] The above transmission system can start smoothly, the motor is driven to rotate by the speed regulator, the motor generates a no-load back electromotive force, which helps the motor to start more smoothly when being powered on, improves the reliability and stability of the motor starting, reduces the mechanical stress of the motor during starting, and prolongs the service life of the motor.

[0038] 2. The transmission system provided by the utility model can avoid the direct impact of the motor on the load during starting by fixing the permanent magnet rotor on the speed regulator shell through the brake before the motor is started. When the motor reaches the rated rotating speed, the brake is released, the permanent magnet rotor starts to rotate, and then drives the load to rotate, so that smooth starting can be realized and the mechanical stress during starting is reduced. Smooth starting can reduce the current peak value during starting of the motor, avoid damage to the motor due to excessive starting current, and prolong the service life of the motor. The speed regulator can flexibly adjust the starting and running parameters of the motor according to different load demands, and is suitable for various working environments and load conditions.

[0039] 3. The transmission system provided by the utility model, the control system includes an inverter, the inverter can convert stable DC power into required AC power, and is suitable for various types of loads. The speed regulator can adjust the speed of the motor as required to realize accurate speed control. The combination of the inverter and the speed regulator can quickly respond to load changes and ensure that the motor can stably operate under different working conditions.

[0040] 4. The transmission system provided by the utility model, the four-quadrant inverter can control the rotation of the motor in the forward and reverse directions, which makes it possible to flexibly control the winding rotor in the winding permanent magnet speed regulator and realize accurate control of the speed by adjusting the frequency and voltage. The bidirectional energy conversion function of the four-quadrant inverter enables the system to operate efficiently in different working modes, whether it is driving the motor or recovering energy. Through accurate control and efficient conversion, the loss of energy in the transmission and conversion process is reduced. The system can realize the forward and reverse working modes by switching the state of the switch, enhancing the flexibility and adaptability of the system. The combination of the four-quadrant inverter and the speed regulator can quickly respond to changes in system requirements and ensure that the system can stably operate under different working conditions. The four-quadrant inverter can realize soft start of the motor, reduce the impact current and mechanical stress during motor start, and improve the running stability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the specific embodiments of the utility model or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the utility model, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0042] Fig. 1 The structural schematic diagram of the transmission system provided by the utility model is shown in the figure.

[0043] Fig. 2 The partial structural schematic diagram of the transmission system provided by the utility model is shown in the figure.

[0044] Fig. 3 The control flow chart of the motor starting process of the utility model is shown in the figure.

[0045] Reference signs:

[0046] 1. Motor, 11. First circuit, 12. First switch, 2. First coupling, 3. Governor, 31. Winding rotor, 32. Permanent magnet rotor, 33. Brake, 34. First rotating shaft, 35. Rotating cylinder, 36. Second rotating shaft, 37. First bearing, 39. Governor housing, 310. Rotating part, 311. Second bearing, 312. Third bearing, 313. Fourth bearing, 4. Collector ring brush holder, 5. Second coupling, 6. Four-quadrant inverter, 61. Second switch, 62. Third switch, 63. Fourth switch, 64. Second circuit, 65. Third circuit, 66. Fourth circuit, 67. Fifth circuit, 7. Power supply, 8. Load. DETAILED DESCRIPTION

[0047] The technical solutions of the utility model will be described clearly and completely in combination with the drawings. Obviously, the described embodiments are some of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all the other embodiments obtained by the ordinary skilled in the art without making creative efforts belong to the protection scope of the utility model.

[0048] In the description of the utility model, it needs to be explained that unless there are explicit provisions and limitations, the terms "mounting", "connection" and "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected, it can be mechanical connection, or electrical connection, it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For the ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0049] In addition, the technical features involved in the different embodiments of the utility model described below can be combined with each other as long as there is no conflict.

[0050] At present, the motor often faces the problems of large starting impact, excessive starting capacity and the like during the starting process. When the motor starts, since the rotor has not rotated, the resistance of the stator winding is relatively low, a large amount of heat will be generated when the starting current is much larger than the normal motor operating current, the temperature of the motor rapidly rises, the high starting torque generated when the motor starts will cause strong mechanical impact on the transmission system, which leads to the increase of the loss of the motor and its driving system and the reduction of the reliability. The existing motor starting scheme fails to effectively solve these problems, so that the starting efficiency and performance of the motor under different working conditions are limited.

[0051] Asynchronous starting and synchronous running is that the motor is directly connected to the power supply for starting, and the motor of this starting mode needs to increase the asynchronous starting squirrel cage, increase the amount of magnetic steel and the size of the iron core of the permanent magnet rotor and the like. This starting mode has the following disadvantages:

[0052] First, because the mouse cage winding will produce a large induced current at start-up, further increase the demand for starting current. The increased amount of magnetic steel and permanent magnet rotor core size will increase the current demand when the motor starts. The above reasons will lead to the starting capacity requirements of the motor is large, generally 9-10 times the rated capacity, load starting capacity may reach 11-13 times, the impact on the power grid.

[0053] Second, high starting current will result in high starting torque when the motor starts, and high starting torque will result in large motor starting impact and short motor starting time. Because the high starting current may exceed the rated capacity of the motor, it cannot be applied to high-power motors.

[0054] The frequency converter starts and runs by adjusting the frequency and voltage of the motor through the frequency converter to achieve smooth start. The frequency converter is the most common way, which can accurately control the starting process, reduce the starting current and provide a wide speed range. However, high-voltage frequency converters are more expensive, and the investment in frequency converters is large, which requires regular maintenance and repair. Once the frequency converter is damaged, the motor cannot obtain the required frequency and voltage to start normally. Moreover, the frequency converter must be always connected in series in the motor system, which increases the complexity of the system and the maintenance workload.

[0055] Therefore, the utility model provides a transmission system, through four quadrant inverter and winding permanent magnet speed regulator's combination, reduce the impact and current consumption when the motor starts, thereby improving the starting performance and overall efficiency of the motor.

[0056] The utility model discloses a small capacity four quadrant inverter forward use, makes the current into the winding rotor of permanent magnet speed regulator, makes the speed regulator permanent magnet rotor start to the rated speed of motor, and the speed regulator permanent magnet rotor drives the synchronous rotation of motor permanent magnet rotor, then instantaneously passes through the power frequency electricity in motor winding and disconnects the power supply of permanent magnet speed regulator winding rotor. The transmission system of the utility model adopts the combination of four quadrant inverter and winding permanent magnet speed regulator, and optimizes the motor starting process. The utility model reduces the starting current and starting impact of the motor by adjusting the output of four quadrant inverter.

[0057] Embodiment 1

[0058] As Figs. 1-2As shown, the embodiment discloses a transmission system, comprising a motor 1, a speed regulator 3, and a control system. The motor 1 is a driving permanent magnet motor. A power supply 7 is used to provide power for the motor 1 and the speed regulator 3. One end of the speed regulator 3 is connected with the motor 1, and the other end of the speed regulator 3 is disconnected with the load before the motor 1 starts, and is connected with the load after the motor 1 starts. The control system is used to control the running state of the motor 1 and the speed regulator 3. Before the motor 1 starts, the control system controls the motor 1 to be disconnected with the power supply 7, so that the motor 1 is powered off, the control system controls the speed regulator 3 to be connected with the power supply 7, so that the speed regulator 3 is powered on, and then the speed regulator 3 drives the motor 1 to rotate, and when the motor 1 reaches its rated speed, the control system controls the speed regulator 3 to be powered off and simultaneously controls the motor 1 to be powered on.

[0059] The above transmission system can reduce the starting impact: the speed regulator 3 can smoothly drive the motor 1 to rotate first, and then the motor 1 can be switched to a direct power supply state after the motor 1 reaches its rated speed. Since the motor 1 has a certain speed when starting, the motor rotor rotates in the magnetic field to generate a back electromotive force, and the existence of the back electromotive force helps to reduce the starting current, thereby avoiding the starting impact on the power grid when the motor 1 is directly connected to the power supply for starting.

[0060] The specific control principle of the transmission system capable of reducing the starting impact is as follows:

[0061] The voltage equation of the permanent magnet motor can be expressed as:

[0062] V = E + I × R

[0063] Wherein: V is the terminal voltage (input voltage), E is the back electromotive force (no-load back electromotive force), I is the starting current of the motor, and R is the stator resistance of the motor;

[0064] When the motor 1 starts, the motor rotor rotates in the magnetic field to generate a back electromotive force E. With the increase of the angular velocity of the motor 1, the back electromotive force E also increases. When the back electromotive force increases, the terminal voltage V needs to overcome the back electromotive force and the resistance voltage drop, resulting in the reduction of the starting current:

[0065] I = (V - E) / R

[0066] Therefore, during the starting process of the motor 1, by adjusting the inverter output voltage V and increasing the motor speed, the back electromotive force E is increased, thereby effectively reducing the starting current and reducing the impact on the power grid. When the motor 1 is in a running state, the motor 1 is connected with the power supply, which can provide a smooth power supply for the motor 1.

[0067] The aforementioned transmission system can reduce starting capacity: since the speed controller 3 provides part of the torque required by the motor 1 in the initial stage, it effectively replaces part of the starting power requirement of the motor 1 to some extent. Therefore, the starting capacity requirement of the power supply will also be reduced, because the motor 1 has already obtained a certain speed and torque through the power supply of the speed controller 3 before reaching a steady state.

[0068] The specific control principle by which the transmission system can reduce the starting capacity is as follows:

[0069] Starting torque T of the motor s and inertial load torque T load The relationship can be represented as:

[0070] T s =K×φ×I

[0071] Where: K is a constant, φ is the magnetic flux of the permanent magnet, and I is the starting current of the motor;

[0072] At the same time, the starting angular velocity ω st and startup time T st It can be represented as:

[0073] ω st =(T S -T load ) / J×T st

[0074] Where: J is the moment of inertia of the motor and the load;

[0075] From the above formula, it can be seen that the starting torque T s It must be greater than or equal to the load torque T load This allows the motor to start. To reduce starting torque and starting shock, this invention employs the following control strategy during startup: By adjusting the inverter output voltage and current, the motor 1 starts with a lower torque in the initial startup phase, avoiding the shock caused by instantaneous high starting torque. The starting angular velocity ω is controlled by adjusting the acceleration process of the motor 1. st This allows it to vary within a stable range, reducing mechanical shock during startup.

[0076] The aforementioned transmission system enables smooth start-up, reduces mechanical stress during motor 1 startup, and extends the motor's service life.

[0077] In some embodiments, the speed regulator 3 is a wound rotor permanent magnet speed regulator, which includes a speed regulator housing 39, a wound rotor 31, a permanent magnet rotor 32, and a brake 33. The wound rotor 31 is rotationally arranged inside the speed regulator housing 39, and is coaxially connected with the output shaft of the motor 1. The permanent magnet rotor 32 is rotationally arranged inside the speed regulator housing 39, and is coaxially connected with the load 8. The brake 33 is an electromagnetic brake, and can also be a mechanical brake. The brake 33 is arranged inside the speed regulator housing 39. The brake 33 has a first position and a second position; before the motor 1 starts, the control system controls the brake 33 to be in the first position, and the permanent magnet rotor 32 is fixedly connected with the speed regulator housing 39. After the motor 1 starts, the control system controls the brake 33 to be in the second position, and the permanent magnet rotor 32 is disconnected with the speed regulator housing 39, the wound rotor 31 is energized, the magnetic field generated by the wound rotor 31 interacts with the magnetic field generated by the permanent magnet rotor 32, to generate an electromagnetic torque, so as to drive the permanent magnet rotor 32 to rotate.

[0078] In the present embodiment, by fixing the permanent magnet rotor 32 on the speed regulator housing 39 through the brake 33 before the motor 1 starts, the direct impact of the motor 1 on the load when the motor 1 starts can be avoided. When the motor 1 reaches the rated speed, the brake 33 is released, and the permanent magnet rotor 32 starts to rotate, driving the load to rotate, so that smooth starting can be achieved, and mechanical stress during starting can be reduced. Smooth starting can reduce the current peak value when the motor 1 starts, avoid damage to the motor due to excessive starting current, and prolong the service life of the motor 1. The speed regulator 3 can flexibly adjust the starting and running parameters of the motor 1 according to different load requirements, and adapt to various working environments and load conditions.

[0079] More specifically, the wound rotor 31 is fixedly arranged on a rotating part 310, the rotating part 310 is fixedly connected with a first rotating shaft 34, and the first rotating shaft 34 is coaxially connected with the output shaft of the motor 1 through the first coupling 2.

[0080] The permanent magnet rotor 32 is fixedly arranged on the inner side wall of a rotating cylinder 35, the first rotating shaft 34 passes through the rotating cylinder 35, and the permanent magnet rotor 32 is located outside the wound rotor 31 and has an air gap with the permanent magnet rotor 32. The air gap can reduce mechanical contact between the permanent magnet rotor 32 and the wound rotor 31, thereby reducing friction loss. The existence of the air gap enables the magnetic field to be effectively transmitted between the wound rotor 31 and the permanent magnet rotor 32, ensuring the generation of the electromagnetic torque.

[0081] One side wall of the rotating cylinder 35 is rotatably arranged on the first rotating shaft 34 through the first bearing 37, and the other side wall of the rotating cylinder 35 is fixedly arranged on the second rotating shaft 36, the second rotating shaft 36 is rotatably arranged on the speed regulator shell 39 through the second bearing 311, and the end of the second rotating shaft 36 extends out of the speed regulator shell 39 and is connected with the load through the second coupling 5. The second rotating shaft 36 is provided with a first rotating shaft accommodating cavity, and the end of the first rotating shaft 34 is located in the first rotating shaft accommodating cavity and is rotatably connected with the second rotating shaft 36 through the third bearing 312, and the other end of the first rotating shaft 34 extends out of the speed regulator shell 39 and is rotatably connected with the speed regulator shell 39 through the fourth bearing 313.

[0082] The second rotating shaft 36 outside the speed regulator shell 39 is provided with a collector ring brush holder 4, the collector ring brush holder 4 is provided with a rotating part, a collector ring and a carbon brush, the rotating part is fixedly connected with the second rotating shaft 36 and can rotate synchronously with the second rotating shaft 36, the collector ring is arranged on the rotating part, the carbon brush is arranged on the collector ring brush holder 4, the carbon brush is in sliding contact with the collector ring, and the carbon brush is electrically connected with the second line 64.

[0083] The principle of fixing and motor conversion of the winding permanent magnet speed regulator is that the permanent magnet rotor 32 of the winding permanent magnet speed regulator is fixed, which is converted into the working state of a permanent magnet motor. By supplying power to the winding on the winding rotor of the winding permanent magnet speed regulator, the permanent magnet rotor 32 is activated, which rotates and is connected with the motor output shaft to drive the rotor of the motor to rotate.

[0084] In some embodiments, the motor 1 is connected with the power supply 7 through the first line 11, the first line 11 is provided with the first switch 12, and the control system is used to control the on-off of the first switch 12 to control the connection between the motor 1 and the power supply 7.

[0085] In some embodiments, the control system includes an inverter, one end of the inverter is electrically connected with the power supply 7, and the other end of the inverter is electrically connected with the speed regulator 3. The inverter can convert stable direct current power into required alternating current, which is suitable for various types of loads. The speed regulator 3 can adjust the rotating speed of the motor 1 as needed to realize precise speed control. The combination of the inverter and the speed regulator 3 can quickly respond to load changes to ensure that the motor 1 can stably operate under different working conditions.

[0086] More specifically, the inverter is a small-capacity four-quadrant inverter 6. The four-quadrant inverter 6 is connected with a second line 64, a third line 65, a fourth line 66 and a fifth line 67. One end of the fifth line 67 is connected with the power supply 7, and the other end of the fifth line 67 is connected with the input end of the four-quadrant inverter 6. One end of the second line 64 is connected with the output end of the four-quadrant inverter 6, and the other end of the second line 64 is connected with the input end of the governor 3. The second line 64 is provided with a second switch 61. One end of the third line 65 is connected with the power supply 7, and the other end of the third line 65 is connected with the second line 64 between the output end of the four-quadrant inverter 6 and the second switch 61. The third line 65 is provided with a third switch 62. One end of the fourth line 66 is connected with the fifth line 67, and the other end of the fourth line 66 is connected with the second line 64 between the second switch 61 and the governor 3. The fourth line 66 is provided with a fourth switch 63.

[0087] The four-quadrant inverter 6 has a forward use state and a reverse use state. Before the motor 1 is started, when it is needed to make the four-quadrant inverter 6 in the forward use state, the second switch 61 is closed to make the governor 3 energized. When the governor 3 drives the motor 1 to reach the rated speed of the motor, the first switch 12 is closed to make the motor 1 energized. After the motor 1 is started, when it is needed to make the four-quadrant inverter 6 in the reverse use state, the second switch 61 is opened, and the third switch 62 and the fourth switch 63 are closed. The slip power generated by the governor 3 is converted into electric energy by the four-quadrant inverter to be fed back to the power supply. Not only the energy waste can be reduced, but also the operation cost of the system can be reduced. The bidirectional energy conversion capability improves the energy utilization efficiency of the system.

[0088] The capacity of the four-quadrant inverter 6:

[0089] According to the characteristics of the winding permanent magnet speed regulation used for the fan and water pump loads,

[0090] P n =(nn / nN) 3 ×P N ,

[0091] P n =T n ×n n

[0092] wherein, P n is the load shaft power, T n is the load shaft torque, P N is the load rated power, n N is the load rated speed, n n is the speed under the speed regulation n;

[0093] The following can be obtained

[0094] In the case of ignoring windage and other losses, T mn = T n ;

[0095] When n mN = n N ,

[0096] Where T mn is the motor output torque, P mn is the motor output power, n mN is the rated speed of the motor.

[0097] The slip power at the speed n can be obtained as

[0098] Since the speed ratio i = n n / n N × 100%, ΔP = P mn -P n = (i 2 -i 3 ) × P N , taking the derivative and setting the derivative equal to zero, i.e. dΔP / di = (2i-3i 2 ) × P N = 0, i = 0, i = 0.667, then the maximum slip power loss is ΔP = 0.148P N . Therefore, the inverter feedback capacity of the four-quadrant inverter is about 14.8% of the system rated capacity.

[0099] In this embodiment, the four-quadrant inverter 6 can control the rotation of the motor in both forward and reverse directions, which makes it possible to flexibly control the winding rotor in the winding permanent magnet speed regulator, and precise control of the speed can be achieved by adjusting the frequency and voltage. The bidirectional energy conversion function of the four-quadrant inverter 6 enables the system to operate efficiently in different modes, whether driving the motor or recovering energy. Through precise control and efficient conversion, the loss of energy in the transmission and conversion process is reduced. The system can realize both forward and reverse working modes by switching the state of the switch, enhancing the flexibility and adaptability of the system. The combination of the four-quadrant inverter 6 and the speed regulator 3 can quickly respond to changes in system demand, ensuring stable operation of the system under different working conditions. The four-quadrant inverter 6 can realize soft start of the motor, reducing the impact current and mechanical stress during motor start-up, and improving the running stability of the system.

[0100] In some embodiments, the control system further comprises a three-phase rectifier circuit arranged between the power supply 7 and the four-quadrant inverter. The power supply is a power frequency power supply, i.e., the power supply in this embodiment is an alternating current power supply. Before the motor 1 starts, the three-phase rectifier circuit converts the three-phase alternating current of the power supply 7 into direct current, and then converts the direct current into alternating current through the four-quadrant inverter to drive the speed regulator 3 to rotate. This two-stage conversion ensures the power quality and stability of the motor during startup. When the motor 1 is running at less than full load, the slip power generated by the speed regulator 3 is converted into direct current by the four-quadrant inverter, and then the direct current is converted into alternating current by the three-phase rectifier circuit to feed back to the power supply 7. This not only reduces energy waste, but also reduces the operating cost of the system. This bidirectional conversion improves the energy utilization efficiency of the system.

[0101] In this embodiment, the three-phase rectifier circuit is added to the control system, which enables the system to more efficiently convert and recover energy during motor startup and non-full load operation. The combination of the three-phase rectifier circuit and the four-quadrant inverter enables the system to operate efficiently in different modes.

[0102] In some embodiments, the control system further comprises a switching power supply circuit for controlling the voltage and current output by the inverter, allowing the motor 1 to start with low torque at the beginning of startup, which can significantly reduce the impact current and mechanical stress during startup, avoiding damage to the motor and related mechanical components. Reducing the startup impact can prolong the service life of the motor and other mechanical components, reducing maintenance costs. Low-torque startup makes the motor 1 more stable during startup, avoiding system instability caused by high startup torque. Low-torque startup can reduce the impact on the power grid and avoid the impact of voltage fluctuations on other equipment.

[0103] And after the motor 1 starts, the voltage and current output by the inverter are controlled to allow the system to quickly respond to load changes to adapt to different load requirements, ensuring stable operation of the motor under different operating conditions.

[0104] The switching power supply circuit is a PWM circuit or a BOOST boost circuit.

[0105] The PWM circuit adjusts the output voltage and current by changing the pulse width, achieving precise control of motor torque and speed. At the beginning of motor startup, the PWM circuit can output a lower duty cycle, thereby achieving low-torque startup of the motor and reducing startup impact.

[0106] The BOOST circuit can boost the input voltage to a higher output voltage, which is suitable for occasions that require high voltage driving. The BOOST circuit can achieve precise control of the output voltage and current by adjusting the on-time and off-time of the switch tube. During motor starting, the BOOST circuit can provide higher starting torque to help the motor reach the rated speed faster.

[0107] Whether it is a PWM circuit or a BOOST circuit, real-time monitoring of load changes can quickly adjust the output voltage and current to adapt to different load requirements. Both PWM and BOOST circuits have fast response capabilities, reducing the system's lag time for load changes, ensuring that the motor always operates in the best state.

[0108] Embodiment 2

[0109] In combination Fig. 3 As shown in the figure, the embodiment discloses a motor starting control method based on a transmission system. The method uses a four-quadrant inverter combined with a winding permanent magnet speed regulator control strategy. During the motor starting process, the motor 1 state is monitored in real time, and the inverter output is adjusted through an intelligent control algorithm to optimize the motor 1 starting process.

[0110] A motor starting control method, specifically comprising the following steps:

[0111] Before the motor 1 starts, the control system controls the first switch 12 between the motor 1 and the power supply 7 to be disconnected, so that the motor 1 is powered off; the four-quadrant inverter in the control system is used in forward direction (the four-quadrant inverter is used as a frequency converter), and the winding rotor 31 in the winding permanent magnet speed regulator is powered, while the brake 33 is controlled to fix the permanent magnet rotor 32 on the speed regulator housing 39. At this time, the winding permanent magnet speed regulator becomes a permanent magnet motor, and the winding rotor 31 of the winding permanent magnet speed regulator drives the rotor of the motor 1 to rotate, so that the motor 1 generates a no-load back electromotive force. Determine whether the rotational speed of the motor 1 rotor reaches its rated speed; when the motor 1 rotor does not reach its rated speed, the current and voltage of the winding rotor 31 input to the winding permanent magnet speed regulator are regulated; when the motor 1 reaches its rated speed, the control system controls the speed regulator 3 to be powered off, and the motor 1 is powered on at the same time, so that the motor 1 starts to reduce the starting impact and starting capacity of the permanent magnet motor.

[0112] Before the motor 1 starts, the state of the motor 1 is monitored in real time during the rotation of the speed regulator 3 driving the motor 1. The voltage and current output by the inverter are controlled through the switching power supply circuit, and then the voltage and current of the winding rotor 31 of the speed regulator 3 are controlled to control the speed of the motor 1. By adjusting the output voltage and current of the inverter, the motor starts with a lower torque at the initial stage to avoid the impact caused by the instantaneous high starting torque. By adjusting the acceleration process of the motor 1, the angular velocity ω st is controlled to change within a stable range, reducing mechanical impact during the starting process. The starting current of the motor can be gradually increased to avoid the impact caused by sudden changes.

[0113] After the motor 1 starts, the current and voltage of the speed regulator rotor are controlled by the inverter, and then the load is slowly started to achieve soft starting and speed regulation of the motor. The specific method is: through the control system, the brake 33 is controlled to be in the second position, and the rotating cylinder 35 connected with the permanent magnet rotor 32 is no longer fixedly connected to the speed regulator shell 39. The winding rotor 31 is energized again, the magnetic field generated by the winding rotor 31 interacts with the magnetic field generated by the permanent magnet rotor 32, and then the permanent magnet rotor 32 drives the load to rotate synchronously with the winding rotor 31 and the motor rotor.

[0114] After the motor 1 starts, during normal operation, the permanent magnet motor drives the winding permanent magnet speed regulator, which in turn drives the fan, water pump square torque load by the winding permanent magnet speed drive. According to the production or process needs, when the load does not need to run at full load, the size of the winding current in the winding permanent magnet speed regulator can be controlled to adjust the output speed and torque to meet the load demand. At this time, the slip power generated by the winding in the winding permanent magnet speed regulator can be led out through the collector ring brush holder, and then reversed through the four-quadrant inverter to convert DC power into AC power frequency power to feed back to the power supply end, thereby achieving the effect of saving electricity.

[0115] After the motor 1 starts, the speed regulator 3 is connected to the load through the control system, and the voltage and current of the winding rotor of the speed regulator are adjusted based on the size of the load to adjust the speed and torque of the motor 1. By adjusting the voltage and current of the speed regulator 3 in real time, the motor 1 can quickly respond to changes in the load to ensure stable operation under different load conditions. When the load suddenly increases or decreases, the speed and torque of the motor 1 can be quickly adjusted to avoid mechanical impact and current fluctuations caused by sudden changes in the load. Through real-time adjustment, the motor 1 can be ensured to operate stably under various load conditions, reducing fluctuations and instability. The control system can automatically adjust according to the load condition to avoid overloading and overheating, providing multiple protection functions to improve the safety of the system.

[0116] Obviously, the above embodiments are only examples for clearly illustrating the present application and are not intended to limit the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be enumerated. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A transmission system characterized by, The utility model relates to a motor (1);Speed regulator (3), one end of speed regulator (3) is connected with motor (1), the other end of speed regulator (3) is disconnected with load before motor (1) starts and is connected with load after motor (1) starts; Control system is used to control the running state of motor (1) and speed regulator (3);Before the motor (1) starts, the control system controls motor (1) and controls speed regulator (3) to be powered on, makes speed regulator (3) drive motor (1) to rotate, when motor (1) reaches its rated speed, the control system controls speed regulator (3) and controls motor (1) to be powered on simultaneously and is powered off. The motor (1) is connected through first circuit (11) between power supply (7), is provided with first switch (12) on first circuit (11), and the control system is used to control the on-off of first switch (12) to control the connection between motor (1) and power supply (7). The control system includes:

2. The transmission system of claim 1, wherein, Inverter, one end of inverter is electrically connected with power supply (7), and the other end of inverter is electrically connected with speed regulator (3).

3. The transmission system of claim 2, wherein, The inverter is four quadrant inverter (6), is connected with second circuit (64), third circuit (65), fourth circuit (66) and fifth circuit (67);One end of fifth circuit (67) is connected with power supply (7), and the other end of fifth circuit (67) is connected with the input end of four quadrant inverter (6);One end of second circuit (64) is connected with the output end of four quadrant inverter (6), and the other end of second circuit (64) is connected with the input end of speed regulator (3), and is provided with second switch (61) on second circuit (64);One end of third circuit (65) is connected with power supply (7), and the other end of third circuit (65) is connected with second circuit (64) between the output end of four quadrant inverter (6) and second switch (61), and is provided with third switch (62) on third circuit (65);One end of fourth circuit (66) is connected with fifth circuit (67), and the other end of fourth circuit (66) is connected with second circuit (64) between second switch (61) and speed regulator (3), and is provided with fourth switch (63) on fourth circuit (66); ​ 4. The transmission system of claim 3, wherein, ​ The four-quadrant inverter (6) has a forward use state and a reverse use state; before the motor (1) starts, when it is needed to make the four-quadrant inverter (6) in the forward use state, the second switch (61) is closed to make the governor (3) energized, when the governor (3) drives the motor (1) to reach the rated speed of the motor, the first switch (12) is closed to make the motor (1) energized; after the motor (1) starts, when it is needed to make the four-quadrant inverter (6) in the reverse use state, the second switch (61) is opened, the first switch (12), the third switch (62) and the fourth switch (63) are closed, the slip power generated by the governor (3) is converted into electric energy by the four-quadrant inverter and fed back to the power supply.

5. The transmission system of claim 4, wherein, The inverter feedback capacity of the four-quadrant inverter (6) is 14.8% of the rated capacity of the system.

6. The transmission system of claim 3, wherein, The control system further comprises: A three-phase rectifier circuit, which is arranged between the power supply (7) and the four-quadrant inverter; The power supply is a power frequency power supply; before the motor (1) starts, the three-phase alternating current of the power supply (7) is converted into direct current by the three-phase rectifier circuit, and then the direct current is converted into alternating current by the four-quadrant inverter to drive the governor (3) to rotate; when the motor (1) is in non-full load operation, the slip power generated by the governor (3) is converted into direct current by the four-quadrant inverter, and then the direct current is converted into alternating current by the three-phase rectifier circuit to feed back to the power supply (7).

7. The transmission system of claim 3, wherein, The control system further comprises: A switching power supply circuit, which is used to control the voltage and current output by the inverter, so that the motor (1) starts with low torque at the initial stage, and quickly responds to load changes after the motor (1) starts.

8. The transmission system of claim 7, wherein, The switching power supply circuit is a PWM circuit or a BOOST boost circuit.

9. A transmission system according to any one of claims 1 to 8, characterised in that, The governor (3) is a winding permanent magnet governor, which comprises: A governor housing (39); A winding rotor (31), which is rotatably arranged inside the governor housing (39) and is coaxially connected with the output shaft of the motor (1); A permanent magnet rotor (32), which is rotatably arranged inside the governor housing (39) and is coaxially connected with the load (8); A brake (33), which is arranged inside the governor housing (39); the brake (33) has a first station and a second station; before the motor (1) starts, the control system controls the brake (33) to be in the first station, and the permanent magnet rotor (32) is fixedly connected with the governor housing (39); after the motor (1) starts, the control system controls the brake (33) to be in the second station, and the permanent magnet rotor (32) is disconnected with the governor housing (39), the winding rotor (31) is energized, and the magnetic field generated by the winding rotor (31) interacts with the magnetic field generated by the permanent magnet rotor (32) to drive the permanent magnet rotor (32) to rotate.

10. The transmission system of claim 9, wherein, The winding rotor (31) is fixedly arranged on a rotating part (310), the rotating part (310) is fixedly connected with a first rotating shaft (34), and the first rotating shaft (34) is coaxially connected with an output shaft of the motor (1) through a first coupling (2); The permanent magnet rotor (32) is fixedly arranged on the inner side wall of the rotating cylinder (35), the permanent magnet rotor (32) is located outside the winding rotor (31) and has an air gap between the winding rotor (31) and the permanent magnet rotor (32); one side wall of the rotating cylinder (35) is rotatably arranged on the first rotating shaft (34), the other side wall of the rotating cylinder (35) is fixedly arranged on a second rotating shaft (36), the second rotating shaft (36) is rotatably arranged on a speed regulator housing (39), and the end of the second rotating shaft (36) extends out of the speed regulator housing (39) and is connected with a load through a second coupling (5).

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