Excitation control circuit with multiple field suppression loops for aviation three-level power generation system

Abstract

The invention discloses an excitation control circuit with multiple field suppression loops for an aviation three-level power generation system. The excitation control circuit comprises a resonance field suppression capacitor C2, a field suppression switch S1, a field suppression switch S2, an anti-reverse diode D1, a fly-wheel diode D2, a fly-wheel diode D3, a transient voltage suppression diode D4, a voltage regulation MOS tube Q1, a voltage regulation MOS tube Q2, a field suppression resistor R1 and an excitation winding L, wherein the positive end DC + of the direct-current power supply is connected to the positive electrode of the anti-reverse diode D1, and the negative electrode of the anti-reverse diode D1 is connected to the negative end DC-of the direct-current power supply through the field suppression switch S1 and the resonance field suppression capacitor C2 in sequence; the negative electrode of the anti-reverse diode D1 is connected with the drain electrode of the voltage-regulating MOS tube Q1, the negative electrode of the fly-wheel diode D3 and one end of the field suppression switch S2, and the source electrode of the voltage-regulating MOS tube Q1 is connected to the positive electrode F + of the excitation winding L and the negative electrode of the fly-wheel diode D2; the positive electrode of the fly-wheel diode D3 is connected to the negative electrode F-of the excitation winding L, the drain electrode of the voltage regulation MOS tube Q2 and the negative electrode of the transient voltage suppression diode D4. The other end of the field suppression switch S2 is connected to the positive electrode of the transient voltage suppression diode D4 and one end of the field suppression resistor R1. And the positive electrode of the fly-wheel diode D2, the source electrode of the voltage-regulating MOS tube Q2 and the other end of the de-excitation resistor R1 are respectively connected to the negative end DC-of the direct-current power supply. According to the technical scheme, the problems that a freewheeling diode added between exciting voltages in an existing exciting circuit cannot consume energy of a magnetic field, and the de-excitation speed is low are solved.

Description

Technical Field

[0001] The present invention relates to the field of generator excitation drive technology, but is not limited to it, and in particular to an excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system. Background Art

[0002] The traditional power generation system has transient voltage changes in transient characteristics due to load changes or engine speed changes, especially when a large load is suddenly unloaded. The traditional method controls the excitation switch tube to form a diode freewheeling circuit, and the excitation current is consumed by the equivalent resistance of the excitation winding to generate heat. The demagnetization time of this demagnetization method is slow, resulting in the electromagnetic energy in the excitation winding not being able to be reduced instantly, further affecting the large voltage transient fluctuations and the long time to recover from the transient to the steady state. Therefore, an effective and fast demagnetization method is particularly critical; in addition, when an overvoltage fault occurs in the DC power supply system, due to the back electromotive force of the excitation winding, the voltage at the voltage regulation point cannot be instantly lowered, thereby failing to minimize the overvoltage fault loss. Therefore, the demand for effective and fast transfer or absorption of excitation winding energy is extremely urgent. Summary of the invention

[0003] Purpose of the present invention: In order to solve the above-mentioned technical problems, an embodiment of the present invention provides an excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system, so as to solve the problem that the freewheeling diode added between the excitation voltages in the existing excitation circuit cannot consume the energy of the magnetic field and the demagnetization speed is slow.

[0004] The technical solution of the present invention: The embodiment of the present invention provides an excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system, including: a resonant demagnetization capacitor C2, a demagnetization switch S1, a demagnetization switch S2, an anti-reverse diode D1, a freewheeling diode D2, a freewheeling diode D3, a transient voltage suppression diode D4, a voltage regulating MOS tube Q1, a voltage regulating MOS tube Q2, a demagnetization resistor R1 and an excitation winding L;

[0005] Among them, the positive terminal DC+ of the DC power supply is connected to the positive electrode of the anti-reverse diode D1, and the negative electrode of the anti-reverse diode D1 is connected to the negative terminal DC- of the DC power supply through the demagnetization switch S1 and the resonant demagnetization capacitor C2 in sequence; the negative electrode of the anti-reverse diode D1 is respectively connected to the drain of the voltage regulating MOS tube Q1, the negative electrode of the freewheeling diode D3 and one end of the demagnetization switch S2, and the source of the voltage regulating MOS tube Q1 is respectively connected to the positive electrode F+ of the excitation winding L and the negative electrode of the freewheeling diode D2; the positive electrode of the freewheeling diode D3 is respectively connected to the negative electrode F- of the excitation winding L, the drain of the voltage regulating MOS tube Q2 and the negative electrode of the transient voltage suppression diode D4, and the other end of the demagnetization switch S2 is respectively connected to the positive electrode of the transient voltage suppression diode D4 and one end of the demagnetization resistor R1; the positive electrode of the freewheeling diode D2, the source of the voltage regulating MOS tube Q2 and the other end of the demagnetization resistor R1 are respectively connected to the negative terminal DC- of the DC power supply.

[0006] Optionally, in the above-mentioned excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system, the voltage regulating MOS tube Q2 in the excitation control circuit is set to a normally open state, and the excitation working mode of the excitation control circuit is:

[0007] Under normal excitation working state, when DC power is input, based on the closed state of demagnetization switch S1, resonant demagnetization capacitor C2 is used as filter capacitor; anti-reverse diode D1 is forward-conducted, and voltage-regulating MOS tube Q1 is controlled to be in open state, and excitation DC power flows into excitation winding after passing through voltage-regulating MOS tube Q1. By adjusting the duty cycle of voltage-regulating MOS tube Q1, the voltage of excitation DC power input to excitation winding L is controlled to achieve the purpose of excitation control.

[0008] Optionally, the excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system as described above further includes: a filter capacitor C1;

[0009] The filter capacitor C1 is connected between the positive terminal DC+ of the DC power supply and the negative terminal DC- of the DC power supply, and is used to filter out the AC component in the input pulsating DC power supply voltage to make the voltage pulsation smooth.

[0010] Optionally, in the excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system as described above,

[0011] Under normal excitation conditions, when the excitation winding L is controlled by adjusting the duty cycle of the excitation voltage regulating MOS tube Q1, demagnetization is achieved by consuming the energy in the excitation winding L during the cut-off time;

[0012] When a high-power load of the power generation system is suddenly added or removed, or when the power generation system fails, demagnetization is achieved by consuming the energy in the excitation winding L;

[0013] The demagnetization is achieved by consuming the energy in the excitation winding L, and at least one of the following demagnetization methods is adopted:

[0014] Mode 1: diode freewheeling demagnetization mode;

[0015] Mode 2, resistance demagnetization mode;

[0016] Mode 3, capacitor resonance demagnetization mode;

[0017] Method 4: combined demagnetization method.

[0018] Optionally, in the above-mentioned excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system, the diode freewheeling demagnetization method of the method 1 is:

[0019] When the demagnetization condition occurs, the input DC power supply is cut off, and the demagnetization switch S1 and the demagnetization switch S2 are both in the off state, and the voltage regulating MOS tube Q1 is controlled to be turned off to stop providing the excitation DC power supply to the excitation winding L;

[0020] Based on the fact that the voltage regulating MOS tube Q2 is in a normally open state, at this time, the voltage regulating MOS tube Q2, the freewheeling diode D2, and the excitation winding L form a first freewheeling demagnetization circuit, and the DC current in the excitation winding L is freewheeled through the freewheeling diode D2. In the freewheeling demagnetization circuit, the excitation DC power supply voltage is lowered through the equivalent resistance of the excitation winding L and the tube voltage drop of the freewheeling diode D2.

[0021] Optionally, in the above-mentioned excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system, the resistance demagnetization method of the method 2 is:

[0022] When the demagnetization condition occurs, the control cuts off the DC power input, controls the voltage regulating MOS tube Q1 and the voltage regulating MOS tube Q2 to be immediately turned off, controls the demagnetization switch S1 to be opened, and controls the demagnetization switch S2 to be closed; the excitation winding L and the forward conducting freewheeling diode D3, the demagnetization switch S2, the demagnetization resistor R1, and the freewheeling diode D2 form a resistance demagnetization circuit, and the demagnetization is achieved by consuming the energy in the excitation winding L through the heat generated by the demagnetization resistor R1.

[0023] Optionally, the excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system as described above includes:

[0024] The transient voltage suppression diode D4 connected to the negative pole F- of the excitation winding L is used to achieve passive overvoltage protection demagnetization under fault conditions, in the following manner: under normal excitation conditions, the negative pole voltage of the excitation winding L is maintained below the voltage limit; when the power generation system suddenly unloads the load, the back electromotive force of the excitation winding L increases instantaneously, so that after the negative pole voltage of the excitation winding L reaches the breakdown voltage of the transient voltage suppression diode D4, the transient voltage suppression diode D4 conducts in the reverse direction, and forms a second freewheeling demagnetization circuit with the excitation winding L through the transient voltage suppression diode D4, the demagnetization resistor R1, the freewheeling diode D2, and the excitation winding L, thereby quickly absorbing the energy of the excitation winding L.

[0025] Optionally, in the above-mentioned excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system, the capacitor resonance demagnetization method of mode 3 is:

[0026] When the demagnetization condition occurs, the control cuts off the DC power input, controls the voltage regulating MOS tube Q1 and the voltage regulating MOS tube Q2 to be turned off immediately, controls the demagnetization switch S1 to be closed, and controls the demagnetization switch S2 to be opened. At this time, the freewheeling diode D2 and the freewheeling diode D3 are forward-conducted, and a capacitive resonant demagnetization circuit is formed through the excitation winding L, the freewheeling diode D3, the demagnetization switch S1, the resonant demagnetization capacitor C2, and the freewheeling diode D2; the equivalent inductance of the excitation winding L in the capacitive resonant demagnetization circuit resonates with the resonant demagnetization capacitor C2, and the excitation voltage in the excitation winding L is fed back into the resonant demagnetization capacitor C2 after passing through the freewheeling diode D3 and the demagnetization switch S1, so that the excitation voltage is rapidly reduced.

[0027] Optionally, in the above-mentioned excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system, the combined demagnetization method of method 4 is:

[0028] When the demagnetization condition occurs, the control cuts off the DC power input, controls the voltage regulating MOS tube Q1 and the voltage regulating MOS tube Q2 to be turned off immediately, controls the demagnetization switch S1 and the demagnetization switch S2 to be closed, and at this time, the freewheeling diode D2 and the freewheeling diode D3 are forward-conducted;

[0029] First, a capacitor resonant demagnetization circuit is formed by the excitation winding L, the flyback diode D3, the demagnetization switch S1, the resonant demagnetization capacitor C2, and the flyback diode D2; the equivalent inductance of the excitation winding L in the capacitor resonant demagnetization circuit resonates with the resonant demagnetization capacitor C2, and a part of the excitation voltage in the excitation winding L is fed back into the resonant demagnetization capacitor C2 through the flyback diode D3 and the demagnetization switch S1, so that the excitation voltage is rapidly reduced;

[0030] Secondly, a resistance demagnetization circuit is formed by the excitation winding L, the freewheeling diode D3, the demagnetization switch S2, the demagnetization resistor R1, and the freewheeling diode D2. The heat generated by the demagnetization resistor R1 consumes the remaining excitation voltage in the excitation winding L to achieve rapid demagnetization.

[0031] Beneficial effects of the present invention: An excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system provided by an embodiment of the present invention aims at the characteristics of the excitation circuit in the aviation three-stage power generation system, and solves the problem that the freewheeling diode added between the excitation voltages in the traditional circuit cannot consume the energy of the magnetic field and the demagnetization speed is slow, and solves the problem that the demagnetization resistor in the traditional circuit realizes rapid demagnetization with characteristic changes; the excitation control circuit with multiple demagnetization circuits provided by an embodiment of the present invention, under normal excitation conditions, when the excitation winding L is controlled by adjusting the duty cycle of the excitation voltage regulating MOS tube Q1, demagnetization is achieved by consuming the energy in the excitation winding L within the cut-off time; in addition, in the event of sudden addition or removal of high-power loads in the power generation system, or failure of the power generation system, multiple demagnetization methods are provided to achieve rapid demagnetization and redundant demagnetization; specifically, demagnetization is achieved by consuming the energy in the excitation winding L, and multiple demagnetization methods such as a diode freewheeling demagnetization method, a resistor demagnetization method, a capacitor resonance demagnetization method and a combined demagnetization method are provided. The excitation control circuit with multiple demagnetization circuits provided in the embodiment of the present invention can not only improve the demagnetization speed of the exciter and further improve the dynamic response capability of the entire power generation system, but also the multiple demagnetization methods are redundant with each other, and can at least guarantee the most basic demagnetization function in the event of a fault; in addition, the excitation control circuit provided by the present invention can also realize overvoltage protection demagnetization when the excitation voltage is too high, thereby ensuring the safe operation of the power generation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0033] Figure 1 A schematic diagram of the circuit structure of an excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system provided by an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the principle of a diode freewheeling demagnetization method of an excitation control circuit with multiple demagnetization circuits is provided for Embodiment 1 of the present invention;

[0035] Figure 3 A schematic diagram of the principle of a resistance demagnetization method of an excitation control circuit with multiple demagnetization circuits is provided for Embodiment 2 of the present invention;

[0036] Figure 4A schematic diagram of the principle of a capacitor resonance demagnetization method of an excitation control circuit with multiple demagnetization circuits is provided for Embodiment 3 of the present invention;

[0037] Figure 5 A schematic diagram of the principle of a combined demagnetization method of an excitation control circuit with multiple demagnetization circuits is provided for Example 2 of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0039] As explained in the above background technology, the demagnetization time of the demagnetization method in the traditional power generation system is relatively slow, which results in that the electromagnetic energy in the excitation winding cannot be reduced instantly. In addition, when an overvoltage fault occurs in the DC power supply system, it is difficult to minimize the overvoltage fault loss. Therefore, the demand for effective and rapid transfer or absorption of the excitation winding energy is extremely urgent.

[0040] At present, there are two main demagnetization methods for excitation circuits: energy transfer and energy consumption. On the one hand, energy transfer is to transfer the energy in the excitation winding to other electronic energy storage elements, so that the voltage of the excitation winding drops rapidly to achieve the effect of demagnetization; such as inverter demagnetization, that is, using full-controlled bridge inverter technology, by controlling the switching state of the inverter to change the direction of the current, so as to achieve the purpose of quickly cutting off the current; but this method is complex to control and difficult to implement. On the other hand, energy consumption is mainly consumed by connecting energy-consuming elements (such as demagnetization resistors) in series or in parallel with the excitation winding. When the excitation machine changes from excitation to demagnetization, the demagnetization resistor is connected to the excitation circuit, and the energy in the excitation winding is consumed as heat energy through the resistor; but the commonly used demagnetization resistors are linear and nonlinear. The nonlinear resistor has a fast demagnetization speed, but has the disadvantages of easy change of characteristics and short service life. The linear resistor has a lower demagnetization speed than the nonlinear resistor. Therefore, a single demagnetization circuit in the same excitation circuit has the problem of difficulty in taking into account the demagnetization speed, practicality and reliability requirements.

[0041] Therefore, designing an excitation circuit with multiple demagnetization circuits has certain practical value, which can improve the rapid demagnetization capability and application reliability of the excitation circuit.

[0042] In order to solve the above problems, an embodiment of the present invention provides an excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system, so as to solve the problem that the three-stage power generation system has large transient fluctuations in normal voltage and a long time for the voltage to recover to a steady state, and optimize the transient characteristics of the three-stage power generation system; and improve the dynamic response capability of the system, and adopt multiple demagnetization methods to be redundant with each other, so as to ensure the basic demagnetization function under normal power generation or faults, and improve the demagnetization reliability.

[0043] The present invention provides the following specific embodiments which can be combined with each other. The same or similar concepts or processes may not be described in detail in some embodiments.

[0044] Figure 1 The circuit structure diagram of an excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the main components of the excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system provided by the embodiment of the present invention include: resonant demagnetization capacitor C2, demagnetization switch S1, demagnetization switch S2, anti-reverse diode D1, freewheeling diode D2, freewheeling diode D3, transient voltage suppression diode D4, voltage regulating MOS tube Q1, voltage regulating MOS tube Q2, demagnetization resistor R1 and excitation winding L. It should be noted that in each embodiment of the present invention, in order to indicate the direction of the excitation current during normal excitation, F+ and F- respectively represent the positive and negative poles of the excitation winding, and DC+ and DC- are the pulsating DC power input after the AC power is rectified.

[0045] like Figure 1 In the structure of the excitation control circuit shown, the positive terminal DC+ of the DC power supply is connected to the positive electrode of the anti-reverse diode D1, and the negative electrode of the anti-reverse diode D1 is connected to the negative terminal DC- of the DC power supply through the demagnetization switch S1 and the resonant demagnetization capacitor C2 in sequence; the negative electrode of the anti-reverse diode D1 is respectively connected to the drain of the voltage regulating MOS transistor Q1, the negative electrode of the freewheeling diode D3 and one end of the demagnetization switch S2, and the source of the voltage regulating MOS transistor Q1 is respectively connected to the positive electrode F+ of the excitation winding L and the negative electrode of the freewheeling diode D2; the positive electrode of the freewheeling diode D3 is respectively connected to the negative electrode F- of the excitation winding L, the drain of the voltage regulating MOS transistor Q2 and the negative electrode of the transient voltage suppression diode D4, and the other end of the demagnetization switch S2 is respectively connected to the positive electrode of the transient voltage suppression diode D4 and one end of the demagnetization resistor R1; the positive electrode of the freewheeling diode D2, the source of the voltage regulating MOS transistor Q2 and the other end of the demagnetization resistor R1 are respectively connected to the negative terminal DC- of the DC power supply.

[0046] Furthermore, the excitation control circuit with multiple demagnetization circuits provided in the embodiment of the present invention further includes: a filter capacitor C1. The filter capacitor C1 is connected between the positive terminal DC+ of the DC power supply and the negative terminal DC- of the DC power supply, and is used to filter out the AC component in the input pulsating DC power supply voltage to smooth the voltage pulsation.

[0047] The excitation control circuit with multiple demagnetization circuits provided by the embodiment of the present invention is not limited to the aviation three-stage power generation system as an application object. When the exciter of the power generation system is normally excitated, the demagnetization switch S1 is closed by default and the demagnetization switch S2 is disconnected. The input pulsating DC power supply voltage first passes through the filter capacitor C1 to filter out the AC component in the DC to smooth the voltage pulsation. If the input is a DC power supply, the filter capacitor C1 can be removed.

[0048] Figure 1 The excitation working principle of the circuit shown is: under normal excitation conditions, when the DC power supply is input, based on the closed state of the demagnetization switch S1, the resonant demagnetization capacitor C2 is used as a filter capacitor; the anti-reverse diode D1 is forward-conducted, and the voltage-regulating MOS tube Q1 is controlled to be in the open state, and the excitation DC power supply flows into the excitation winding after passing through the voltage-regulating MOS tube Q1. The voltage of the excitation DC power supply input to the excitation winding L is controlled by adjusting the duty cycle of the voltage-regulating MOS tube Q1 to achieve the purpose of excitation control.

[0049] The excitation control circuit with multiple demagnetization circuits provided in the embodiment of the present invention, under normal excitation conditions, when the excitation winding L is controlled by adjusting the duty cycle (i.e., on / off) of the excitation voltage regulating MOS tube Q1, in order to achieve a more ideal excitation voltage regulating effect, demagnetization is achieved by consuming the energy in the excitation winding L within the cut-off time. In addition, in the case of sudden addition or removal of high-power loads in the power generation system, or failure of the power generation system, rapid demagnetization is also required; in view of the above situation, the present invention provides a variety of demagnetization methods to achieve rapid demagnetization and redundant demagnetization. In the specific implementation, demagnetization is achieved by consuming the energy in the excitation winding L; at least one of the following demagnetization methods is used:

[0050] Mode 1: diode freewheeling demagnetization mode;

[0051] This demagnetization method is a traditional demagnetization method for generators. The demagnetization speed is slow. The demagnetization circuit only relies on the voltage drop of the freewheeling diode and the equivalent resistance consumption of the excitation winding. It is suitable for occasions where the demagnetization speed requirement is not high. The specific demagnetization principle is shown in the following embodiment 1.

[0052] Mode 2, resistance demagnetization mode;

[0053] This method is to connect a high-power demagnetization resistor to the excitation winding to form a loop during demagnetization, and consume the energy of the excitation winding in the form of heat through the resistor. In addition, when the excitation DC source voltage suddenly increases and the duty cycle of the voltage regulator is not adjusted in time, the excitation current will increase, and the generated voltage will exceed the specified range of transient changes.

[0054] According to the characteristic that the voltage at the negative end F- of the excitation also increases, a transient voltage suppression diode is provided. When the voltage at the negative end F- of the excitation exceeds the steady-state range, the transient voltage suppression diode breaks down and conducts, and the demagnetization resistor is connected to the excitation circuit to demagnetize to realize transient overvoltage protection. The specific demagnetization principle is shown in the following Example 2.

[0055] Mode 3, capacitor resonance demagnetization mode;

[0056] This method mainly uses the resonance effect of LC to absorb the energy in the excitation winding through the capacitor. This method is mainly used for demagnetization under high-frequency excitation control. The specific demagnetization principle is shown in Example 3.

[0057] Mode 4, combined demagnetization mode;

[0058] Combining resistance demagnetization with capacitance resonance demagnetization can further improve the demagnetization speed; the specific demagnetization principle is shown in the following embodiment 4.

[0059] The embodiment of the present invention provides an excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system. In view of the characteristics of the excitation circuit in the aviation three-stage power generation system, the invention aims to solve the problem that the freewheeling diode added between the excitation voltages in the traditional circuit cannot consume the energy of the magnetic field and the demagnetization speed is slow, and to solve the problem that the demagnetization resistor in the traditional circuit realizes rapid demagnetization with characteristic changes. The excitation control circuit with multiple demagnetization circuits provided by the embodiment of the present invention realizes demagnetization by consuming the energy in the excitation winding L within the cut-off time under normal excitation conditions when the excitation winding L is controlled by adjusting the duty cycle of the excitation voltage regulating MOS tube Q1. In addition, in the event of sudden addition or removal of high-power loads in the power generation system, or failure of the power generation system, multiple demagnetization modes are provided to realize rapid demagnetization and redundant demagnetization. Specifically, demagnetization is realized by consuming the energy in the excitation winding L, and multiple demagnetization modes such as a diode freewheeling demagnetization mode, a resistor demagnetization mode, a capacitor resonance demagnetization mode, and a combined demagnetization mode are provided. The excitation control circuit with multiple demagnetization circuits provided in the embodiment of the present invention can not only improve the demagnetization speed of the exciter and further improve the dynamic response capability of the entire power generation system, but also the multiple demagnetization methods are redundant with each other, and can at least guarantee the most basic demagnetization function in the event of a fault; in addition, the excitation control circuit provided by the present invention can also realize overvoltage protection demagnetization when the excitation voltage is too high, thereby ensuring the safe operation of the power generation system.

[0060] The specific manner of achieving demagnetization by the excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system provided by the embodiment of the present invention is described below through some embodiments.

[0061] Reference Figure 1 The excitation control circuit with multiple demagnetization circuits for the aviation three-stage power generation system shown in the figure performs demagnetization by the methods provided in the following four embodiments during the cut-off time of the voltage regulating MOS tube Q1 and when the power generation system load is suddenly increased or unloaded or a power generation system failure occurs and demagnetization is required. Any one of the demagnetization methods can be selected. Embodiments 1 to 3 are respectively a demagnetization method, and embodiment 4 is a combination of embodiment 2 and embodiment 3; and the four demagnetization methods provided by the four embodiments are redundant with each other.

[0062] Embodiment 1:

[0063] Figure 2 A schematic diagram of the principle of a diode freewheeling demagnetization method of an excitation control circuit with multiple demagnetization circuits is provided for Example 1 of the present invention.

[0064] This embodiment 1 provides a freewheeling demagnetization method for the freewheeling diode D2;

[0065] This demagnetization method is the traditional demagnetization method for generators. Figure 2 As shown, the specific demagnetization method is: during the cut-off time of the voltage regulating MOS tube Q1, and when the load of the power generation system is suddenly added or unloaded, or a fault occurs in the power generation system and demagnetization is required, the excitation circuit is switched from excitation to demagnetization (i.e., a demagnetization condition occurs), the DC power input is controlled to be cut off, the demagnetization switch S1 and the demagnetization switch S2 are controlled to be disconnected, and the voltage regulating MOS tube Q1 is immediately turned off through the control signal to stop providing the excitation DC power supply to the excitation winding L. Since the voltage regulating MOS tube Q2 is in a normally open state, the voltage regulating MOS tube Q2, the freewheeling diode D2, and the excitation winding L form a first freewheeling demagnetization circuit, and the DC current in the excitation winding L is freewheeled through the freewheeling diode D2, and the excitation DC power supply voltage is pulled down in the freewheeling demagnetization circuit through the equivalent resistance of the excitation winding L and the tube voltage drop of the freewheeling diode D2.

[0066] Embodiment 2:

[0067] Figure 3 A schematic diagram of the principle of a resistance demagnetization method of an excitation control circuit with multiple demagnetization circuits is provided for Example 2 of the present invention.

[0068] This embodiment 2 provides a resistor demagnetization method (overvoltage protection): This demagnetization method mainly converts the energy in the excitation winding L into heat dissipation through the demagnetization resistor R1 to achieve rapid demagnetization. Figure 3As shown in the figure, when the demagnetization condition occurs, the control cuts off the DC power input, and the voltage regulating MOS tube Q1 and the voltage regulating MOS tube Q2 are immediately turned off through the control signal. The demagnetization switch S1 is opened and the demagnetization switch S2 is closed by the program in the system, and the excitation winding L and the forward conducting freewheeling diode D3, the demagnetization switch S2, the demagnetization resistor R1, and the freewheeling diode D2 form a resistance demagnetization circuit, and the energy in the excitation winding L is consumed by the heat generated by the demagnetization resistor R1 to achieve rapid demagnetization.

[0069] The resistance demagnetization method provided in this embodiment 2 also has overvoltage protection capability, and the implementation principle is:

[0070] Connecting a transient voltage suppression diode D4 to the negative pole F- side of the excitation winding L can achieve passive overvoltage protection demagnetization under fault conditions. Under normal excitation conditions, the negative pole voltage of the excitation winding L is maintained below a certain voltage limit. When the power generation system suddenly unloads the load, especially a large load, due to the inductance characteristics of the excitation winding L, the back electromotive force of the excitation winding L increases instantly, so that the negative pole voltage of the excitation winding L reaches the breakdown voltage of the transient voltage suppression diode D4, and the transient voltage suppression diode D4 quickly reverse conducts, and forms a second freewheeling demagnetization circuit with the transient voltage suppression diode D4, the demagnetization resistor R1, the freewheeling diode D2 and the excitation winding L to quickly absorb the energy of the excitation winding L and optimize the transient characteristics of the power generation system.

[0071] Embodiment 3:

[0072] Figure 4 A schematic diagram of the principle of a capacitor resonance demagnetization method of an excitation control circuit with multiple demagnetization circuits is provided for Example 3 of the present invention.

[0073] This embodiment 3 provides a capacitor resonance demagnetization method: This method is mainly used for demagnetization under high-frequency excitation control, such as Figure 4 As shown, when the excitation circuit works normally, the voltage regulating MOS tube Q1 is turned on / off according to the duty cycle, and the voltage regulating MOS tube Q2 is continuously turned on. The excitation voltage of the excitation winding L is adjusted by controlling the duty cycle of the voltage regulating MOS tube Q1.

[0074] When a fault occurs and demagnetization is required, the control cuts off the DC power input, controls the voltage regulating MOS tube Q1 and the voltage regulating MOS tube Q2 to be quickly turned off, controls the demagnetization switch S1 to be closed, and controls the demagnetization switch S2 to be opened. Because the current in the excitation winding L will not change suddenly, at this time, the freewheeling diode D2 and the freewheeling diode D3 are forward-conducted, and the excitation winding L, the freewheeling diode D3, the demagnetization switch S1, the resonant demagnetization capacitor C2, and the freewheeling diode D2 form a capacitor resonant demagnetization circuit. The equivalent inductance of the excitation winding L in the capacitor resonant demagnetization circuit resonates with the resonant demagnetization capacitor C2, and the excitation voltage in the excitation winding L is fed back into the resonant demagnetization capacitor C2 after passing through the freewheeling diode D3 and the demagnetization switch S1, so that the excitation voltage is rapidly reduced.

[0075] In addition, the freewheeling diodes D2 and D3 have the ability to prevent reverse resonance of the circuit. The function of the anti-reverse diode D1 is mainly to isolate the filter capacitor C1. During demagnetization, only the capacitor C2 participates in the resonant demagnetization.

[0076] Embodiment 4:

[0077] Figure 5 A schematic diagram of the principle of a combined demagnetization method of an excitation control circuit with multiple demagnetization circuits is provided for Example 2 of the present invention.

[0078] This embodiment 4 provides a combined demagnetization method of capacitor resonance demagnetization and resistor demagnetization, that is, a comprehensive demagnetization method of the two demagnetization methods of embodiment 2 and embodiment 3. Figure 5 As shown, when the demagnetization condition occurs, the DC power input is cut off, the voltage regulating MOS tube Q1 and the voltage regulating MOS tube Q2 are immediately turned off, and the demagnetization switch S1 and the demagnetization switch S2 are both closed; because the current in the excitation winding L will not change suddenly, at this time, the freewheeling diode D2 and the freewheeling diode D3 are forward-conducted.

[0079] On the one hand, a capacitive resonant demagnetization circuit is formed by the excitation winding L, the freewheeling diode D3, the demagnetization switch S1, the resonant demagnetization capacitor C2, and the freewheeling diode D2; the equivalent inductance of the excitation winding L in the capacitive resonant demagnetization circuit resonates with the resonant demagnetization capacitor C2, and a portion of the energy in the excitation winding L (a portion of the excitation voltage) is fed back into the resonant demagnetization capacitor C2 via the freewheeling diode D3 and the demagnetization switch S1, so that the excitation voltage is rapidly reduced.

[0080] On the other hand, the excitation winding L and the forward-conducting freewheeling diode D3, the demagnetization switch S2, the demagnetization resistor R1, and the freewheeling diode D2 form a resistance demagnetization circuit, which consumes the remaining energy (the remaining excitation voltage) in the excitation winding L through the heat generated by the demagnetization resistor R1 to achieve rapid demagnetization.

[0081] In this embodiment 4, since the energy in the excitation winding is consumed respectively through two demagnetization methods, compared with the separate demagnetization in embodiments 2 and 3, the combined demagnetization speed will be greatly improved. Therefore, this demagnetization method uses the LC resonance combined resistance demagnetization method to increase the demagnetization speed and realize rapid demagnetization of the generator excitation system, thereby further improving the dynamic response capability of the system.

[0082] Although the embodiments disclosed in the present invention are as above, the contents are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. An excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system, characterized in that: include: Resonant demagnetization capacitor C2, demagnetization switch S1, demagnetization switch S2, anti-reverse diode D1, freewheeling diode D2, freewheeling diode D3, transient voltage suppression diode D4, voltage regulating MOS tube Q1, voltage regulating MOS tube Q2, demagnetization resistor R1 and excitation winding L; Among them, the positive terminal DC+ of the DC power supply is connected to the positive electrode of the anti-reverse diode D1, and the negative electrode of the anti-reverse diode D1 is connected to the negative terminal DC- of the DC power supply through the demagnetization switch S1 and the resonant demagnetization capacitor C2 in sequence; the negative electrode of the anti-reverse diode D1 is respectively connected to the drain of the voltage regulating MOS tube Q1, the negative electrode of the freewheeling diode D3 and one end of the demagnetization switch S2, and the source of the voltage regulating MOS tube Q1 is respectively connected to the positive electrode F+ of the excitation winding L and the negative electrode of the freewheeling diode D2; the positive electrode of the freewheeling diode D3 is respectively connected to the negative electrode F- of the excitation winding L, the drain of the voltage regulating MOS tube Q2 and the negative electrode of the transient voltage suppression diode D4, and the other end of the demagnetization switch S2 is respectively connected to the positive electrode of the transient voltage suppression diode D4 and one end of the demagnetization resistor R1; the positive electrode of the freewheeling diode D2, the source of the voltage regulating MOS tube Q2 and the other end of the demagnetization resistor R1 are respectively connected to the negative terminal DC- of the DC power supply.

2. The excitation control circuit with multiple demagnetization circuits for aviation three-stage power generation system according to claim 1, characterized in that: The voltage regulating MOS tube Q2 in the excitation control circuit is set to a normally open state, and the excitation working mode of the excitation control circuit is: Under normal excitation working state, when DC power is input, based on the closed state of demagnetization switch S1, resonant demagnetization capacitor C2 is used as filter capacitor; anti-reverse diode D1 is forward-conducted, and voltage-regulating MOS tube Q1 is controlled to be in open state, and excitation DC power flows into excitation winding after passing through voltage-regulating MOS tube Q1. By adjusting the duty cycle of voltage-regulating MOS tube Q1, the voltage of excitation DC power input to excitation winding L is controlled to achieve the purpose of excitation control.

3. The excitation control circuit with multiple demagnetization circuits for aviation three-stage power generation system according to claim 1, characterized in that: Also includes: filter capacitor C1; The filter capacitor C1 is connected between the positive terminal DC+ of the DC power supply and the negative terminal DC- of the DC power supply, and is used to filter out the AC component in the input pulsating DC power supply voltage to make the voltage pulsation smooth.

4. The excitation control circuit with multiple demagnetization circuits for an aviation three-stage power generation system according to any one of claims 1 to 3, characterized in that: Under normal excitation conditions, when the excitation winding L is controlled by adjusting the duty cycle of the excitation voltage regulating MOS tube Q1, demagnetization is achieved by consuming the energy in the excitation winding L during the cut-off time; When a high-power load of the power generation system is suddenly added or removed, or when the power generation system fails, demagnetization is achieved by consuming the energy in the excitation winding L; The demagnetization is achieved by consuming the energy in the excitation winding L, and at least one of the following demagnetization methods is adopted: Mode 1: diode freewheeling demagnetization mode; Mode 2, resistance demagnetization mode; Mode 3, capacitor resonance demagnetization mode; Method 4: combined demagnetization method.

5. The excitation control circuit with multiple demagnetization circuits for aviation three-stage power generation system according to claim 4, characterized in that: The diode freewheeling demagnetization method of method 1 is: When the demagnetization condition occurs, the input DC power supply is cut off, and the demagnetization switch S1 and the demagnetization switch S2 are both in the off state, and the voltage regulating MOS tube Q1 is controlled to be turned off to stop providing the excitation DC power supply to the excitation winding L; Based on the fact that the voltage regulating MOS tube Q2 is in a normally open state, at this time, the voltage regulating MOS tube Q2, the freewheeling diode D2, and the excitation winding L form a first freewheeling demagnetization circuit, and the DC current in the excitation winding L is freewheeled through the freewheeling diode D2. In the freewheeling demagnetization circuit, the excitation DC power supply voltage is lowered through the equivalent resistance of the excitation winding L and the tube voltage drop of the freewheeling diode D2.

6. The excitation control circuit with multiple demagnetization circuits for aviation three-stage power generation system according to claim 4, characterized in that: The resistance demagnetization method of method 2 is: When the demagnetization condition occurs, the control cuts off the DC power input, controls the voltage regulating MOS tube Q1 and the voltage regulating MOS tube Q2 to be immediately turned off, controls the demagnetization switch S1 to be opened, and controls the demagnetization switch S2 to be closed; the excitation winding L and the forward conducting freewheeling diode D3, the demagnetization switch S2, the demagnetization resistor R1, and the freewheeling diode D2 form a resistance demagnetization circuit, and the demagnetization is achieved by consuming the energy in the excitation winding L through the heat generated by the demagnetization resistor R1.

7. The excitation control circuit with multiple demagnetization circuits for aviation three-stage power generation system according to any one of claim 6, characterized in that: include: The transient voltage suppression diode D4 connected to the negative pole F- of the excitation winding L is used to achieve passive overvoltage protection demagnetization under fault conditions, in the following manner: under normal excitation conditions, the negative pole voltage of the excitation winding L is maintained below the voltage limit; when the power generation system suddenly unloads the load, the back electromotive force of the excitation winding L increases instantaneously, so that after the negative pole voltage of the excitation winding L reaches the breakdown voltage of the transient voltage suppression diode D4, the transient voltage suppression diode D4 conducts in the reverse direction, and forms a second freewheeling demagnetization circuit with the excitation winding L through the transient voltage suppression diode D4, the demagnetization resistor R1, the freewheeling diode D2, and the excitation winding L, thereby quickly absorbing the energy of the excitation winding L.

8. The excitation control circuit with multiple demagnetization circuits for aviation three-stage power generation system according to claim 4, characterized in that: The capacitor resonance demagnetization method of method 3 is: When the demagnetization condition occurs, the control cuts off the DC power input, controls the voltage regulating MOS tube Q1 and the voltage regulating MOS tube Q2 to be turned off immediately, controls the demagnetization switch S1 to be closed, and controls the demagnetization switch S2 to be opened. At this time, the freewheeling diode D2 and the freewheeling diode D3 are forward-conducted, and a capacitive resonant demagnetization circuit is formed through the excitation winding L, the freewheeling diode D3, the demagnetization switch S1, the resonant demagnetization capacitor C2, and the freewheeling diode D2; the equivalent inductance of the excitation winding L in the capacitive resonant demagnetization circuit resonates with the resonant demagnetization capacitor C2, and the excitation voltage in the excitation winding L is fed back into the resonant demagnetization capacitor C2 after passing through the freewheeling diode D3 and the demagnetization switch S1, so that the excitation voltage is rapidly reduced.

9. The excitation control circuit with multiple demagnetization circuits for aviation three-stage power generation system according to claim 4, characterized in that: The combined demagnetization method of method 4 is: When the demagnetization condition occurs, the control cuts off the DC power input, controls the voltage regulating MOS tube Q1 and the voltage regulating MOS tube Q2 to be turned off immediately, controls the demagnetization switch S1 and the demagnetization switch S2 to be closed, and at this time, the freewheeling diode D2 and the freewheeling diode D3 are forward-conducted; First, a capacitor resonant demagnetization circuit is formed by the excitation winding L, the flyback diode D3, the demagnetization switch S1, the resonant demagnetization capacitor C2, and the flyback diode D2; the equivalent inductance of the excitation winding L in the capacitor resonant demagnetization circuit resonates with the resonant demagnetization capacitor C2, and a part of the excitation voltage in the excitation winding L is fed back into the resonant demagnetization capacitor C2 through the flyback diode D3 and the demagnetization switch S1, so that the excitation voltage is rapidly reduced; Secondly, a resistance demagnetization circuit is formed by the excitation winding L, the freewheeling diode D3, the demagnetization switch S2, the demagnetization resistor R1, and the freewheeling diode D2. The heat generated by the demagnetization resistor R1 consumes the remaining excitation voltage in the excitation winding L to achieve rapid demagnetization.

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