Speed regulation device for wound-rotor motor using excitation eddy current and wound-rotor motor

Abstract

The utility model discloses a speed regulation device for a wound-rotor motor using excitation eddy current. The speed regulation device comprises a given speed acquisition circuit, a feedback speed acquisition circuit, a speed closed-loop integrating circuit, an oscillating circuit and a silicon controlled rectifier control circuit, the given speed acquisition circuit acquires a given voltage in direct proportion to a given speed; the feedback speed acquisition circuit acquires feedback voltage which is directly proportional to the fed-back rotor rotating speed of the wound-rotor motor; the speed closed-loop integrating circuit compares the obtained given voltage with the feedback voltage, determines speed deviation, and generates control voltage by utilizing proportional-integral control according to the speed deviation; the oscillation circuit responds to the control voltage and generates oscillation voltage; the silicon controlled rectifier control circuit responds to the oscillation voltage and generates excitation eddy current used for being connected to a rotor of the wound-rotor motor. A rotor of the wound-rotor motor rotates at a speed close to a given speed in response to excitation eddy currents. Therefore, elements are few, heat dissipation performance is good, and long-time operation at high temperature can be achieved.

Description

Technical Field

[0001] This utility model belongs to the field of industrial automation technology, specifically relating to a speed regulating device for a wound-rotor motor that utilizes excitation eddy currents. Background Technology

[0002] In the metallurgical industry, overhead crane systems, such as hoisting cranes in steel plants, widely utilize wound-rotor electric motors. Crane speed control equipment includes tachogenerators and speed regulators.

[0003] The production process generates a lot of dust and high temperatures, creating a harsh operating environment for the equipment. This makes the speed control equipment prone to damage, which in turn affects the production schedule.

[0004] Therefore, there is a need to provide speed control devices for wound-rotor motors that can operate for extended periods in harsh environments such as high temperatures. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a speed control device for wound-rotor motors that utilizes excitation eddy currents, thereby solving the technical problem of easy damage to speed control equipment for wound-rotor motors used in crane systems in the metallurgical field.

[0006] In a first aspect, this utility model provides a speed control device for a wound-rotor motor using excitation eddy current, comprising: a given speed acquisition circuit, a feedback speed acquisition circuit, a speed closed-loop integration circuit, an oscillation circuit, and a thyristor control circuit.

[0007] The given speed acquisition circuit acquires a given voltage that is directly proportional to the given speed;

[0008] The feedback speed acquisition circuit acquires a feedback voltage that is directly proportional to the rotor speed of the wound-rotor motor.

[0009] The speed closed-loop integral circuit compares the obtained given voltage and the feedback voltage to determine the speed deviation, and generates a control voltage based on the speed deviation using proportional-integral control.

[0010] The oscillation circuit generates an oscillation voltage in response to the control voltage;

[0011] The thyristor control circuit responds to the oscillation voltage and generates excitation eddy currents for input to the rotor of the wound-rotor motor.

[0012] The rotor of the wound-rotor motor responds to the excitation eddy current and rotates at a speed close to the given speed.

[0013] Furthermore, the given speed includes a first gear and a second gear, wherein the rotor speed indicated by the second gear is greater than the rotor speed indicated by the first gear.

[0014] Furthermore, the given speed acquisition circuit includes: relay DS1, relay DS2, first high-speed switching diode D15, second high-speed switching diode D16, variable resistor R73, and variable resistor R74.

[0015] When the given speed is set to the first gear, the normally open contact of relay DS1 closes and the normally open contact of relay DS2 opens, controlling the second high-speed switching diode D16 to adjust the variable resistor R73, thereby adjusting the speed to the first gear and obtaining the given speed.

[0016] When the given speed is set to the second gear, the normally open contact of relay DS2 closes and the normally open contact of relay DS1 closes. By controlling the first high-speed switching diode D15, the variable resistor R74 is adjusted to perform the second gear speed adjustment and obtain the given speed.

[0017] Furthermore, the feedback speed acquisition circuit includes: operational amplifier U3A, resistor R38, resistor R37, diode D19, and field-effect transistor Q4;

[0018] When the rotor voltage is used to generate the feedback speed, the voltage is transformed through the negative feedback circuit composed of operational amplifier U3A, resistor R38, diode D19 and field-effect transistor Q4, so that the feedback speed is the largest when the rotor voltage is 0 and the feedback speed is the smallest when the rotor voltage is the highest.

[0019] The transformed feedback speed is output through resistor R37.

[0020] Furthermore, the speed closed-loop integrator circuit includes: diode D24, capacitor C17, capacitor C18, resistor R32, and resistor R33.

[0021] When the feedback speed is greater than the given speed, diode D24 is reverse cut off, charging capacitor C17 connected in series with resistor R32 and capacitor C18 connected in series with resistor R33, and the output voltage increases according to the charging constant.

[0022] When the given speed is greater than the feedback speed, capacitor C17 connected in series with resistor R32 and capacitor C18 connected in series with resistor R33 discharge respectively, and the output voltage decreases.

[0023] When the given speed equals the feedback speed, diode D24 is forward-biased, and the output voltage is locked to 0V.

[0024] Furthermore, the speed closed-loop integrator circuit includes: variable resistor R70, variable resistor R71, operational amplifier U2B, diode D21, and diode D22;

[0025] When the output voltage of operational amplifier U2B is positive, diode D22 is turned on and diode D21 is turned off. Adjust the variable resistor R70 to change the integral time constant for speed regulation at the first or second speed.

[0026] When the output voltage of operational amplifier U2B is negative, diode D22 is cut off and diode D21 is turned on. Adjust variable resistor R71 to change the integral time constant for speed control at level 1 or level 2.

[0027] Furthermore, the oscillation circuit includes: a pulse transformer T2, diodes D31 and D32, capacitor C21, resistor R19, capacitor C22, and resistor R17; wherein diodes D31 and D32 are connected in parallel, capacitor C21 is connected in parallel with resistor R19, and capacitor C22 is connected in parallel with resistor R17.

[0028] The oscillation output FOUT and the synchronization voltage SYN output oscillation voltage;

[0029] Output terminals K, G1, and G2 are used to connect to the corresponding terminals of the two thyristors in the thyristor control circuit, respectively.

[0030] Furthermore, the thyristor control circuit includes: thyristor Q10 and thyristor Q11; thyristor Q10 and thyristor Q11 are turned on at the conduction angle in the upper half-wave and lower half-wave respectively, generating excitation eddy currents that act on the rotor shaft of the motor.

[0031] Furthermore, it also includes: a power supply control circuit;

[0032] The control power supply circuit provides a dual-voltage DC power supply of ±15V, including: a transformer, a rectifier module, and a voltage regulator module;

[0033] The voltage regulator module includes: a three-terminal positive voltage regulator and a three-terminal negative voltage regulator;

[0034] The rectifier module includes: 4 rectifier diodes; the transformer converts the AC380V or AC220V AC mains power supplied through the main circuit to a 24VAC low voltage;

[0035] The 24VAC low voltage is rectified by the rectifier module and then regulated by the voltage regulator module to obtain +15V and -15V DC.

[0036] Secondly, this utility model provides a wound-rotor electric motor, comprising:

[0037] As described in the first aspect, a speed control device for a wound-rotor motor using excitation eddy currents.

[0038] The speed control device for wound-rotor motors using excitation eddy currents provided by this utility model has fewer components, better heat dissipation, is suitable for harsh application environments, has good stability, high reliability, small size, is easy to use, has a simple speed control method, low cost, and can operate for a long time at high temperatures. It has been widely used in manufacturing enterprises.

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0040] The exemplary embodiments of this utility model can be more fully understood by referring to the following figures:

[0041] Figure 1 This is a schematic diagram of the composition of a speed control device for a wound-rotor motor using excitation eddy current, according to an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the control power supply circuit in a speed regulating device for a wound-rotor motor using excitation eddy current, according to an embodiment of this utility model.

[0043] Figure 3 This is a schematic diagram of the given speed acquisition circuit and part of the speed closed-loop integration circuit in the speed control device for a wound-rotor motor using excitation eddy current according to an embodiment of the present invention.

[0044] Figure 4 This is a schematic diagram of the motor speed feedback circuit in a speed control device for a wound-rotor motor using excitation eddy current, according to an embodiment of the present invention.

[0045] Figure 5 This is a schematic diagram of the speed closed-loop integral circuit in the speed control device for a wound-rotor motor using excitation eddy current, according to an embodiment of this utility model.

[0046] Figure 6 This is a schematic diagram of the oscillation circuit principle for realizing excitation eddy current in a speed control device for a wound-rotor motor using excitation eddy current, according to an embodiment of this utility model.

[0047] Figure 7 This is a schematic diagram of the thyristor control circuit in a speed regulating device for a wound-rotor motor using excitation eddy current, according to an embodiment of the present invention.

[0048] Figure 8 This is a schematic diagram of the thyristor control in a speed regulating device for a wound-rotor motor using excitation eddy current, according to an embodiment of the present invention.

[0049] Figure 9 This is a schematic diagram illustrating the speed regulation principle of a speed control device for a wound-rotor motor. Detailed Implementation

[0050] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the present invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the present invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0051] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0052] In order to accurately describe the technical content of this utility model and to accurately understand this utility model, the following explanations or definitions of the terms used in this specification are given before describing the specific embodiments.

[0053] Wound-rotor asynchronous motors have advantages such as simple structure, easy manufacturing, and low cost. Eddy current speed control is one of the most reliable speed control methods for asynchronous motors, offering convenient operation and high reliability. Eddy current speed control changes the excitation torque by altering the magnitude of the motor's excitation current, thereby regulating the motor rotor speed or the motor speed itself.

[0054] like Figure 9 As shown, in a speed control device or speed regulator for a wound-rotor motor, the regulating resistor acts as a tachogenerator to obtain the rotor voltage of the motor. Specifically, the high-voltage end of the regulating resistor R is connected to the high-voltage end of the motor rotor (e.g., voltage level 25V-300V), the low-voltage end of the regulating resistor R is connected to the motor rotor grounding terminal (e.g., AGND, voltage level 0V) or the speed regulator grounding terminal (e.g., AGND or DGND, voltage level 0V), and the regulating end of the regulating resistor is connected to the first terminal (e.g., terminal 1) or the second terminal (e.g., terminal 2) of the speed regulator. In this way, the regulating resistor acts as a voltage divider resistor for the tachogenerator or rotor voltage speed feedback voltage, limiting the feedback voltage between 0-30V.

[0055] The present invention provides a speed control device for wound-rotor motors that utilizes excitation eddy currents, which is applied in crane systems in the metallurgical field to achieve speed control of wound-rotor motors.

[0056] The speed control device for wound-rotor motors using excitation eddy currents in this embodiment of the invention increases or decreases the motor's braking torque and thus adjusts the motor speed by inputting excitation eddy currents into the rotor. In other words, it uses excitation eddy currents to generate braking torque for braking and speed reduction.

[0057] In some embodiments, motor speed control is divided into first and second gears at low speeds, which is a stepped or graded speed control. At low speeds (such as first and second gears, or below 30% of the nominal speed), the given speed and the feedback speed are compared; when the feedback speed is greater than the given speed, the excitation eddy current is increased to increase the braking torque and reduce the motor speed; when the given speed is greater than the feedback speed, the excitation eddy current is reduced to decrease the excitation torque, thereby increasing the motor speed, thus forming a closed-loop speed control. At high speeds (such as third gear and above, or above 30% of the nominal speed), the speed control device is closed, and the motor speed operates in an open loop, without the need for feedback speed.

[0058] Thus, in the low-speed gears of the motor, such as first or second gear, the speed control device adjusts the excitation eddy currents acting on the rotor based on the difference between the given speed and the feedback speed, thereby adjusting (e.g., decreasing or increasing) the motor speed. In the high-speed gears of the motor, such as third gear, the speed control device is shut down, and the feedback speed is not required. For example, by removing the rotor resistance from the feedback speed acquisition circuit, the motor can operate in open loop.

[0059] Specifically, two or three buttons are provided to set the second-level low-speed current value or the third-level current value. Specifically, normally open contacts of a relay are used to set the speed range. Thus, the buttons are used to set the three-level current value.

[0060] Specifically, a multi-digit LED display is used to show the actual current. The LED display, along with buttons, is used to set and view parameters. For example, it allows setting three current setpoints, viewing the actual operating current value, and viewing the actual setpoint value.

[0061] like Figure 1 As shown, the speed control device for a wound-rotor motor using excitation eddy current in this embodiment of the present invention includes: a control power supply circuit, a given speed acquisition circuit, a feedback speed acquisition circuit, a speed closed-loop integral circuit, an oscillation circuit for realizing excitation eddy current, and a thyristor control circuit.

[0062] The given speed acquisition circuit acquires a given voltage that is directly proportional to the given speed;

[0063] The feedback speed acquisition circuit acquires a feedback voltage that is directly proportional to the rotor speed of the wound-rotor motor.

[0064] The speed closed-loop integral circuit compares the obtained given voltage and the feedback voltage to determine the speed deviation, and generates a control voltage based on the speed deviation using proportional-integral control.

[0065] The oscillation circuit generates an oscillation voltage in response to the control voltage;

[0066] The thyristor control circuit responds to the oscillation voltage and generates excitation eddy currents for input to the rotor of the wound-rotor motor.

[0067] The rotor of the wound-rotor motor responds to the excitation eddy current and rotates at a speed close to the given speed.

[0068] The above process involves isolating the actual current, adjusting the isolated current data, performing analog-to-digital conversion on the adjusted current, and comparing the resulting digital signal with the given current (i.e., the given speed). The compared signal is then used to generate a control signal via a PI controller. This control signal is sent to the oscillation circuit, which generates a conduction angle pulse signal. This pulse signal is then sent to the thyristor control circuit to set the thyristor's conduction angle or to switch the thyristor on and off, thereby changing the magnitude of the actual current, altering the excitation torque, and ultimately adjusting the speed to the given speed.

[0069] This excitation eddy current speed control device features a simple structure, convenient speed regulation, high reliability, adaptability to harsh operating environments, small size, and easy replacement. It has been widely used in the speed regulation of wound-rotor motors in the metallurgical field. Compared with existing technologies, this speed regulation method is simple and reliable, has fewer components in the regulator, facilitates heat dissipation, and has a long service life.

[0070] like Figure 2 As shown, in the control power supply circuit, transformer T1 converts the AC380V or AC220V AC mains power supplied through the main circuit (via L1 and L2) into a 24VAC low voltage. After being rectified by the rectifier module, the 24VAC low voltage continues to pass through the Zener diodes in the voltage regulator module (including the three-terminal positive regulator LM7815 and the three-terminal negative regulator LM7915) to obtain +15V (such as P15) and -15V (such as N15) DC power supplies, respectively.

[0071] Thus, the control power supply circuit provides a ±15V dual-voltage DC power supply as the control power supply for the excitation eddy current speed regulation device, and transforms the mains voltage from the workshop or factory main circuit into 24V voltage through transformer T1.

[0072] Specifically, the primary side of transformer T1 has two contacts for connecting to AC220V and AC380V respectively. In some embodiments, the AC380V contact is defaulted to being connected to the line voltage L1 of the main circuit. Naturally, it can be modified as needed to connect the AC220V contact to the phase voltage of the main circuit; the primary side of transformer T1 is also connected to the ground L2 of the main circuit.

[0073] Specifically, the secondary side of transformer T1 is used to realize a dual-circuit low-voltage AC power supply. When connected to 380V, the single-ended output of the secondary side of the transformer under no-load conditions is ±26V, and after friction loss, it reaches ±24V in the control circuit, which is the aforementioned 24VAC low voltage.

[0074] The low-voltage AC power supply is rectified and converted into a dual-voltage DC power supply. Specifically, after DC voltage conversion and regulation by a Zener diode, a DC ±15V control power supply voltage is obtained, with voltage output points of +15V (P15) and -15V (N15).

[0075] Specifically, the low-voltage AC power supply is converted into +15V (P15) and -15V (N15) DC power supplies through the three-terminal positive regulator LM7815 and the three-terminal negative regulator LM7915, respectively.

[0076] In some embodiments, the rectifier module consists of a full-bridge rectifier circuit composed of four 1N4007 rectifier diodes (such as D101, D102, D103, and D104), wherein the output DC voltage is equal to The effective value of low-voltage AC voltage is times that of the previous value.

[0077] In some embodiments, electrolytic capacitors (C4, C5) and correction capacitors (C6, C7) are provided before and after the Zener diodes 7815 and 7915 to filter and remove voltage spikes, effectively reducing DC voltage ripple and voltage fluctuations.

[0078] In some embodiments, Figure 2 The LED D11 in the diagram is a power indicator light; it illuminates when the control power supply voltage is normal.

[0079] like Figure 3 As shown, the given speed acquisition circuit includes logic circuits for the given speed of the low speed gear (first or second gear) and the closed signal of the high speed gear; each gear is connected to the power signal (including P15 and N15) by dry contacts, and after voltage adjustment by potentiometer, the voltage conversion circuit composed of operational amplifier outputs the given voltage as the given speed signal; the given voltage is directly proportional to the given speed.

[0080] Referring to the foregoing description, the given speed includes a first gear and a second gear, wherein the rotor speed indicated by the second gear is greater than the rotor speed indicated by the first gear. Referring to the foregoing description, a normally open relay contact is used to set the gear.

[0081] like Figure 3 As shown, when the given speed is set to the first gear, the normally open contact of relay DS1 is closed (the normally open contact of relay DS2 is open), and the variable resistor R73 is adjusted by controlling the second high-speed switching diode IN4148 or D16 to adjust the first gear speed; when the given speed is set to the second gear, the normally open contact of relay DS2 is closed (and the normally open contact of relay DS1 is closed), and the variable resistor R74 is adjusted by controlling the first high-speed switching diode IN4148 or D15 to adjust the second gear speed and obtain the given speed.

[0082] When the given speed is three gears, the given speed acquisition circuit or adjustment device is shut down through the interface signal to realize the high-speed gear shutdown signal.

[0083] like Figure 3 As shown, when the motor is set to first gear, the first gear relay DS1 closes, and a +15V voltage (P15) is applied to the anode of the first gear output rectifier diode D18 (e.g., IN4007). The cathode of the first gear output rectifier diode D18 is connected to the first gear voltage divider resistor R61 and the first gear variable resistor R73. Thus, by adjusting the first gear variable resistor R73, the output voltage of the first gear output diode D16 is adjusted, which serves as the set voltage corresponding to the first gear speed. This should be understood as manual adjustment after the speed control device is installed, requiring no modification during application.

[0084] When the motor is set to second gear (second gear needs to overcome first gear; when second gear is set, first gear relay DS1 remains closed), second gear relay DS2 closes. +15V voltage (P15) is applied to variable resistor R74 through diode D12. By adjusting variable resistor R74, the voltage division between R74 and resistor R55 is changed. The output voltage, through second gear output diode D15, is simultaneously applied to output resistor R52 along with the first gear set voltage. The output voltage of output resistor R52 serves as the set voltage corresponding to the second gear speed. This should be understood as requiring manual adjustment after the speed control device is installed and no modification is needed during application.

[0085] XS is the measurement point for the given speed, which can be conveniently measured using a multimeter or similar device during maintenance. Thus, the given speed corresponds to a given voltage. If the given speed and given voltage are directly proportional, for example, if the given voltage is 10V and the given speed is synchronous speed, then 10% of the synchronous speed corresponds to a given voltage of 1V.

[0086] Figure 3In the diagram, K60 is the normally open contact of the external relay. When closed, it connects to a +15V voltage to increase the set speed; it serves as an auxiliary setting. GV is used to identify the set speed terminal. See the following explanation. Figure 5 In this process, the given speed GV is compared with the feedback speed FKV to form a closed loop.

[0087] In a negative feedback integrator circuit, the output c(t) is proportional to the integral of the input r(t):

[0088]

[0089] in, T i The integration time constant; the integration time constant T i The smaller the value, the stronger the integral effect in the negative feedback integrator circuit.

[0090] like Figure 3 As shown, the integral time constant is adjusted via variable resistors R70 and R71. Specifically, when the output voltage of operational amplifier U2B is positive, diode D22 is on and diode D21 is off. Adjusting variable resistor R70 changes the integral current or integral time constant for speed control at level one or level two. Similarly, when the output voltage of operational amplifier U2B is negative, diode D22 is off and D21 is on. Adjusting variable resistor R71 changes the integral current or integral time constant for speed control at level one or level two. Variable resistors R71 and R70 are voltage divider adjustment resistors after the regulator output. Furthermore, the given voltage GV corresponding to the given speed is transformed by two negative feedback integrator circuits composed of operational amplifiers U2B and U3B, along with resistors and capacitors, to achieve smooth speed control.

[0091] like Figure 4 As shown, in the speed feedback stage, a tachogenerator is used to obtain the rotor voltage of the motor.

[0092] The rotor voltage signal and the tachogenerator signal are rectified and regulated by a variable resistor, and then converted by different circuits to generate the tachogenerator speed feedback signal and the rotor voltage speed feedback signal, which are then input to the speed regulator to participate in closed-loop control.

[0093] There are two methods for speed feedback: one is to use a tachogenerator to achieve speed feedback, and the other is to use rotor voltage to achieve speed feedback. The voltage conversion principle of speed feedback using a tachogenerator is the opposite of that of speed feedback using rotor voltage. Therefore, different conversion circuits are required when generating feedback voltage or feedback speed based on input voltage.

[0094] like Figure 4As shown, when the rotor voltage is used to generate the feedback speed, the rotor voltage needs to be divided before it is connected to the feedback terminals X1:1 and X1:2. The divided rotor voltage, such as 30V, is then connected to the feedback terminals X1:1 and X1:2. In other words, the rotor voltage is connected to the feedback terminals X1:1 and X1:2 after being divided.

[0095] Typically, the rotor voltage of an electric motor is at its highest when it is stalled. When the motor starts, the rotor voltage is relatively high (generally exceeding 300V). The rotor voltage is not directly proportional to the speed; after the motor starts, the voltage is highest at low speeds and lowest at high speeds.

[0096] like Figure 4 As shown, when the rotor voltage is used to generate the feedback speed, a negative feedback circuit consisting of operational amplifier U3A, resistor R38, diode D19, and field-effect transistor Q4 is needed for voltage transformation. This ensures that the feedback speed is maximized when the rotor voltage is 0, which corresponds to the highest output voltage at the speed feedback terminal; conversely, the feedback speed is minimized when the rotor voltage is maximized, which corresponds to the lowest output voltage or a relatively low voltage at the speed feedback terminal. Specifically, the transformed voltage is output to terminal V via resistor R37.

[0097] like Figure 4 As shown, when using a tachogenerator to generate feedback speed, depending on the generator parameters (such as the number of pole pairs and synchronous speed) and the tachogenerator parameters (such as 60V corresponding to 1000 rpm), if the output voltage of the tachogenerator is large, voltage division is also required to divide the voltage at the highest speed to 30V. For example, an external voltage divider resistor can be used to divide the 300V voltage to 30V.

[0098] like Figure 4 As shown, the obtained feedback voltage FKV is DC. Specifically, because the polarity is opposite when the motor rotates forward and backward, it will become the same polarity after rectification. The obtained feedback voltage is rectified by a rectifier bridge (such as D1, D2, D3, and D4), and then divided by a precision resistor R82 and a variable resistor R83. The magnitude of the feedback speed can be adjusted by adjusting the variable resistor R83.

[0099] like Figure 4 As shown, when a tachogenerator is used to generate feedback speed, the output is sent to Cs, the connection point for speed feedback, via resistors R44 and R43 and capacitor C16. The generated feedback speed is flexibly obtained according to the specific feedback method selected. When the feedback speed generated by the tachogenerator forms negative feedback, terminal COM is soldered to terminal Cs; when the feedback speed generated by the rotor voltage forms negative feedback, terminal COM is soldered to terminal V.

[0100] like Figure 4As shown, the feedback voltage corresponding to the feedback speed is finally output through terminal FKV and introduced into... Figure 5 The speed closed-loop integrator circuit shown.

[0101] like Figure 5 In the speed closed-loop integrator circuit shown, the difference between the given voltage GV corresponding to the given speed and the feedback voltage FKV corresponding to the feedback speed is used to form a closed loop; the integrator module is used to generate the control signal A.

[0102] Referring to the above explanation, the given voltage GV connected through terminal GV is positive, and the feedback voltage FKV connected through terminal FKV is negative. In order to compare the magnitudes of the two, it is necessary to compare the absolute values ​​(usually, the given speed and the feedback speed are in the same direction, only the values ​​are different).

[0103] When the feedback speed is greater than the given speed, diode D24 is reverse cut off, charging capacitor C17 (in series with R32) and capacitor C18 (in series with R33), and the output voltage increases according to the charging constant.

[0104] When the given speed is greater than the feedback speed, capacitor C17 (connected in series with R32) and capacitor C18 (connected in series with R33) discharge respectively, and the output voltage decreases.

[0105] When the given speed equals the feedback speed (e.g., the given voltage equals the feedback voltage), when the output voltage decreases to 0V, diode D24 is forward-biased, and the output voltage is locked at 0V.

[0106] Specifically, when the feedback speed is greater than the given speed (the actual speed is too fast and eddy current braking is required), the output voltage of the operational amplifier U2D is positive. The output voltage is divided by resistors R201, R202 and variable resistor R200. The resistance value of variable resistor R200 is adjusted to regulate the excitation eddy current of the output.

[0107] like Figure 5 As shown, the output excitation eddy current is further converted by a negative feedback circuit composed of two operational amplifiers U3C and U3D before being output through terminal A. The first operational amplifier U3C is an inverting proportional amplifier, converting the input voltage into a voltage with the opposite sign and equal absolute value, i.e., converting the input voltage into an equivalent negative voltage. The circuit composed of the second operational amplifier U3D converts the voltage amplitude; the voltage with the smallest absolute value outputs a negative voltage with the largest amplitude, and the input negative voltage with the largest absolute value outputs a negative voltage with the smallest amplitude.

[0108] Specifically, when the feedback speed is less than the given speed (the actual speed is too slow and eddy current excitation is required), the output voltage of the operational amplifier U2D is positive. The output voltage is divided by resistors R201, R202 and variable resistor R200. The resistance value of variable resistor R200 is adjusted to regulate the excitation eddy current of the output.

[0109] like Figure 6 In the oscillation circuit shown, the output value A corresponding to the excitation eddy current and the periodic voltage of the negative terminal OCF of the power transformer rectifier circuit form an oscillation circuit (U1A, U1C), which generates an oscillation output and outputs it through the terminal FOUT.

[0110] like Figure 6 As shown, in the speed feedback loop, the pulse output signal controls the magnitude of the excitation eddy current; based on the magnitude of the control signal, the conduction angle of the thyristor in the main circuit of the excitation eddy current is adjusted to control the magnitude of the excitation eddy current and thus regulate the speed of the motor. Figure 6 As shown, the control signal A and the OCF dynamically adjust the conduction angle of the thyristor, thereby adjusting the magnitude of the excitation eddy current, and thus controlling the motor speed to adjust to the given speed.

[0111] like Figure 7 As shown, in the thyristor control circuit, the oscillation output FOUT and the synchronization voltage SYN (the synchronization voltage for the excitation eddy current) output oscillation voltage control the conduction angle of the thyristor, thus performing excitation eddy current control. T2 is a pulse transformer, isolated from the main circuit, and its outputs K, G1, and G2 are respectively connected to two thyristors (…). Figure 8 On the corresponding poles of the thyristors Q10 and Q11 shown, these two thyristors conduct at the conduction angles in the upper and lower half waves respectively, generating excitation eddy currents of the motor that act on the motor rotor shaft. The eddy current coil, which is coaxial with the motor rotor, outputs current that rotates in the magnetic field to form braking torque that acts on the motor shaft.

[0112] Specifically, Figure 7 In the circuit, diodes D31 and D32 are connected in parallel, capacitor C21 is connected in parallel with resistor R19, and capacitor C22 is connected in parallel with resistor R17.

[0113] In some embodiments, the braking torque of the motor is adjusted by using excitation eddy currents, thereby adjusting the motor speed; the speed feedback circuit uses rotor voltage feedback.

[0114] The tachogenerator solution requires additional speed feedback components, which is not conducive to cost savings.

[0115] This should be understood as follows: all the circuits mentioned above are printed on the PCB board, the discrete components are mounted on the motherboard via connectors, and the packaged components are mounted on the PCB board or motherboard according to their package parameters. The digital tube and buttons are located on the front panel or rear panel, and the front panel, rear panel, and motherboard are located on the front, rear, or inside of the chassis.

[0116] In terms of motor speed regulation, this eddy current braking speed regulation method has the following advantages compared with other technologies:

[0117] 1. The speed adjustment method is simple, reliable, durable, not easily damaged, and has a long service life;

[0118] 2. It is suitable for harsh environments, has good heat dissipation, and due to the small number of components, discrete components can be used. It has a large heat dissipation space and can be used in dusty and dirty environments.

[0119] 3. Low cost, small size, and convenient transportation, installation, and replacement.

[0120] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0121] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

[0123] The above description is illustrative only and not restrictive of this utility model. Those skilled in the art will understand that many modifications, variations or equivalents can be made without departing from the spirit and scope defined by the claims, and all such modifications, variations or equivalents will fall within the protection scope of this utility model.

Claims

1. A speed regulating device for a wound-rotor motor using excitation eddy currents, characterized in that, include: Given speed acquisition circuit, feedback speed acquisition circuit, speed closed-loop integration circuit, oscillation circuit, and thyristor control circuit; The given speed acquisition circuit acquires a given voltage that is directly proportional to the given speed; The feedback speed acquisition circuit acquires a feedback voltage that is directly proportional to the rotor speed of the wound-rotor motor. The speed closed-loop integral circuit compares the obtained given voltage and the feedback voltage to determine the speed deviation, and generates a control voltage based on the speed deviation using proportional-integral control. The oscillation circuit generates an oscillation voltage in response to the control voltage; The thyristor control circuit responds to the oscillation voltage and generates excitation eddy currents for input to the rotor of the wound-rotor motor. The rotor of the wound-rotor motor responds to the excitation eddy current and rotates at a speed close to the given speed.

2. The speed regulating device for a wound-rotor motor using excitation eddy current as described in claim 1, characterized in that, The given speed includes a first gear and a second gear, wherein the rotor speed indicated by the second gear is greater than the rotor speed indicated by the first gear.

3. The speed regulating device for a wound-rotor motor using excitation eddy current as described in claim 2, characterized in that, The given speed acquisition circuit includes: relay DS1, relay DS2, first high-speed switching diode D15, second high-speed switching diode D16, variable resistor R73, and variable resistor R74. When the given speed is set to the first gear, the normally open contact of relay DS1 closes and the normally open contact of relay DS2 opens, controlling the second high-speed switching diode D16 to adjust the variable resistor R73, thereby adjusting the speed to the first gear and obtaining the given speed. When the given speed is set to the second gear, the normally open contact of relay DS2 closes and the normally open contact of relay DS1 closes. By controlling the first high-speed switching diode D15, the variable resistor R74 is adjusted to perform the second gear speed adjustment and obtain the given speed.

4. The speed regulating device for a wound-rotor motor using excitation eddy current as described in claim 1, characterized in that, The feedback speed acquisition circuit includes: operational amplifier U3A, resistor R38, resistor R37, diode D19, and field-effect transistor Q4; When the rotor voltage is used to generate the feedback speed, the voltage is transformed through the negative feedback circuit composed of operational amplifier U3A, resistor R38, diode D19 and field-effect transistor Q4, so that the feedback speed is the maximum when the rotor voltage is 0 and the feedback speed is the minimum when the rotor voltage is the highest. The transformed feedback speed is output through resistor R37.

5. The speed regulating device for a wound-rotor motor using excitation eddy current as described in claim 1, characterized in that, The speed closed-loop integrator circuit includes: diode D24, capacitor C17, capacitor C18, resistor R32, and resistor R33. When the feedback speed is greater than the given speed, diode D24 is reverse cut off, charging capacitor C17 connected in series with resistor R32 and capacitor C18 connected in series with resistor R33, and the output voltage increases according to the charging constant. When the given speed is greater than the feedback speed, capacitor C17 connected in series with resistor R32 and capacitor C18 connected in series with resistor R33 discharge respectively, and the output voltage decreases. When the given speed equals the feedback speed, diode D24 is forward-biased, and the output voltage is locked to 0V.

6. The speed regulating device for a wound-rotor motor using excitation eddy current as described in claim 1, characterized in that, The speed closed-loop integrator circuit includes: variable resistor R70, variable resistor R71, operational amplifier U2B, diode D21, and diode D22; When the output voltage of operational amplifier U2B is positive, diode D22 is turned on and diode D21 is turned off. Adjust the variable resistor R70 to change the integral time constant for speed regulation at the first or second speed. When the output voltage of operational amplifier U2B is negative, diode D22 is cut off and diode D21 is turned on. Adjust variable resistor R71 to change the integral time constant for speed control at level 1 or level 2.

7. The speed regulating device for a wound-rotor motor using excitation eddy current as described in claim 1, characterized in that, The oscillation circuit includes: a pulse transformer T2, diodes D31 and D32, capacitor C21, resistor R19, capacitor C22, and resistor R17; wherein diodes D31 and D32 are connected in parallel, capacitor C21 is connected in parallel with resistor R19, and capacitor C22 is connected in parallel with resistor R17. The oscillation output FOUT and the synchronization voltage SYN output oscillation voltage; Output terminals K, G1, and G2 are used to connect to the corresponding terminals of the two thyristors in the thyristor control circuit, respectively.

8. The speed regulating device for a wound-rotor motor using excitation eddy current as described in claim 1, characterized in that, The thyristor control circuit includes: thyristor Q10 and thyristor Q11; thyristor Q10 and thyristor Q11 are turned on at the conduction angle in the upper half-wave and lower half-wave respectively, generating excitation eddy currents that act on the rotor shaft of the motor.

9. The speed regulating device for a wound-rotor motor using excitation eddy current as described in claim 1, characterized in that, Also includes: Control power supply circuit; The control power supply circuit provides a dual-voltage DC power supply of ±15V, including: a transformer, a rectifier module, and a voltage regulator module; The voltage regulator module includes: a three-terminal positive voltage regulator and a three-terminal negative voltage regulator; The rectifier module includes: 4 rectifier diodes; the transformer converts the AC380V or AC220V AC mains power supplied through the main circuit to a 24VAC low voltage; The 24VAC low voltage is rectified by the rectifier module and then regulated by the voltage regulator module to obtain +15V and -15V DC.

10. A wound-rotor electric motor, characterized in that, include: Speed ​​control device for wound-rotor motors using excitation eddy currents as described in any one of claims 1 to 9.

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