Switching circuit for magnetic bearing power amplifier

Abstract

The present invention is applicable to the technical field of magnetic bearing switch circuits, and provides a switch circuit for a magnetic bearing power amplifier, the circuit comprising: a power switch tube, a delayed on-off module, and an energy discharge module; the delayed on-off module is used to make the switch voltage of the power switch tube zero before it is turned on, and the switch voltage slowly increases after it is turned off; the energy discharge module is used to discharge the energy in the delayed on-off module when the power switch tube is turned on. By adding the delayed on-off module, the switch voltage of the power switch tube is zero before it is turned on, and the switch voltage slowly increases after it is turned off, thereby avoiding the phenomenon of overlapping current and voltage waveforms during the on-off and off-off processes of the power switch tube, effectively reducing the switch loss, and discharging energy through the energy discharge module after the power switch tube is turned on, effectively ensuring the safety of the switch circuit.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic bearing switch circuits, and in particular relates to a switch circuit for a magnetic bearing power amplifier. Background Art

[0002] Power amplifiers are widely used in magnetic bearing actuator circuits due to their high efficiency, fast response speed, and wide bandwidth. Power amplifiers generally use power switch tubes as switching devices. Power switch tubes are not ideal devices, and their turn-on and turn-off are not instantaneous. In this way, the current and voltage waveforms will overlap during the turn-on and turn-off process, resulting in turn-on loss and turn-off loss.

[0003] Therefore, it is particularly important to reduce the conduction loss and turn-off loss of the power switch tube in the magnetic bearing execution circuit. Summary of the invention

[0004] In order to solve the above technical problem, the present invention provides a switching circuit for a magnetic bearing power amplifier.

[0005] In the present invention, by adding a delayed on-off module, the switching voltage of the power switch tube is made zero before it is turned on, and the switching voltage is slowly increased after it is turned off, thereby avoiding the phenomenon of overlapping current and voltage waveforms during the on-and-off process of the power switch tube, effectively reducing switching losses, and discharging energy through the energy discharge module after the power switch tube is turned on, effectively ensuring the safety of the switching circuit.

[0006] Specifically, the switch circuit for the magnetic bearing power amplifier provided by the present invention includes: a power switch tube, a delayed on-off module, and an energy discharge module;

[0007] The delayed on-off module is used to make the switch voltage of the power switch tube zero before it is turned on, and to slowly increase the switch voltage after it is turned off;

[0008] The energy discharge module is used to discharge the energy in the delayed on-off module when the power switch tube is turned on.

[0009] Preferably, the delayed on-off module includes a resonance module and an auxiliary switch tube electrically connected to each other, and the resonance module generates resonance when the auxiliary switch tube is turned on, so that its switching voltage is reduced in advance before the power switch tube is turned on, and the increase of its switching voltage is delayed after the power switch tube is turned off.

[0010] Preferably, the resonance module includes a resonance capacitor and a resonance inductor; the resonance inductor is electrically connected to the auxiliary switch tube and then connected in parallel with the resonance capacitor.

[0011] Preferably, the auxiliary switch tube is a triode, which is turned on when the power switch tube is turned off, and is turned off when the power switch tube is turned on.

[0012] Preferably, the energy discharge module includes a diode, and the diode is connected between the delayed on-off module and the load.

[0013] Preferably, the circuit further comprises a pulse modulation module, the pulse modulation module is electrically connected to the power switch tube and the delayed on-off module, and the pulse modulation module is used to provide a control level to the power switch tube and the delayed on-off module.

[0014] In the switching circuit for the magnetic bearing power amplifier shown in the present invention, a delayed on-off module is added so that the switching voltage of the power switch tube is zero before it is turned on, and the switching voltage is slowly increased after it is turned off, thereby avoiding the phenomenon of overlapping current and voltage waveforms during the on-and-off process of the power switch tube, effectively reducing switching losses, and discharging energy through the energy discharge module after the power switch tube is turned on, effectively ensuring the safety of the switching circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a structural schematic diagram of a switch circuit for a magnetic bearing power amplifier shown in an embodiment of the present invention.

[0017] Figure 2 It is a specific circuit diagram of a switch circuit for a magnetic bearing power amplifier shown in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments:

[0020] As attached Figure 1As shown, the switch circuit for the magnetic bearing power amplifier provided in this embodiment includes: a power switch tube 1, a delayed on-off module 2, and an energy discharge module 3. The delayed on-off module 2 is used to make the switch voltage of the power switch tube 1 zero before it is turned on, and the switch voltage slowly increases after it is turned off; the energy discharge module 3 is used to discharge the energy in the delayed on-off module 3 when the power switch tube 1 is turned on.

[0021] From the above, it can be seen that by adding a delayed on-off module, the switching voltage of the power switch tube is made zero before it is turned on, and the switching voltage slowly increases after it is turned off, thereby avoiding the phenomenon of overlapping current and voltage waveforms during the on-and-off process of the power switch tube, effectively reducing switching losses, and dissipating energy through the energy discharge module after the power switch tube is turned on, effectively ensuring the safety of the switching circuit.

[0022] Specifically, the delayed on-off module 2 includes a resonance module and an auxiliary switch tube that are electrically connected to each other. The resonance module generates resonance when the auxiliary switch tube is turned on, so that its switching voltage is reduced in advance before the power switch tube 1 is turned on, and the increase of its switching voltage is delayed after the power switch tube 1 is turned off.

[0023] Specifically, the resonance module includes a resonant capacitor and a resonant inductor. The resonant inductor is electrically connected to the auxiliary switch tube and then connected in parallel with the resonant capacitor. The auxiliary switch tube is a triode. The triode is turned on when the power switch tube 1 is turned off, and is turned off when the power switch tube 1 is turned on.

[0024] Specifically, the energy discharge module 3 includes a diode, and the diode is connected between the delayed on-off module 2 and the load.

[0025] Specifically, the circuit further includes a pulse modulation module, which is electrically connected to the power switch tube 1 and the delayed on-off module 2 , and is used to provide a control level to the power switch tube 1 and the delayed on-off module 2 .

[0026] For example, the control level output by the pulse modulation module is connected to the base of the power switch tube 1 , and the control level output by the pulse modulation module is connected to the base of the auxiliary switch tube in the delay on-off module 2 after being inverted.

[0027] Figure 2 FIG. 1 is a specific circuit diagram of a switch circuit for a magnetic bearing power amplifier according to this embodiment. Figure 2 As shown, the circuit includes two power switch tubes, namely VT1 and VT2; the load includes an equivalent inductor L1 and an equivalent resistor R1.

[0028] For the power switch tube VT1, the resonance module in the delayed on-off module includes (resonant capacitor C1, resonant inductor L2), the auxiliary switch tube in the delayed on-off module is the transistor V1, and the energy discharge module is the diode D3.

[0029] Before the power switch tube VT1 is turned on, the auxiliary switch tube V1 is turned on first, and the resonant capacitor C1 and the resonant inductor L2 form a resonant circuit. The load L1 is very large and can be regarded as a constant current source during the resonance process. The effect on the resonance is very small and can be ignored. During the resonance process, the current of L2 increases and the voltage of C1 decreases until the voltage across C1 drops to zero. The reverse diode D1 of VT1 is turned on, clamping the voltage across C1 to zero, and the current of L2 remains unchanged. This state is maintained until VT1 is turned on and V1 is turned off. Since VT1 is turned on under zero voltage, there is no conduction loss. When VT1 is turned on, V1 is turned off, and the energy in L2 is transmitted to the load side through the diode D3. Its current decreases linearly, while the current in VT1 increases linearly until the current is equal to the current in L1, and the circuit is turned on normally.

[0030] After the power switch tube VT1 is turned off, the power supply U charges the capacitor C1, which greatly slows down the speed at which the voltage across VT1 increases, and effectively reduces the turn-off loss of the power switch tube VT1.

[0031] Similarly, for the power switch tube VT2, the resonance module in the delayed on-off module includes (resonant capacitor C2, resonant inductor L3), the auxiliary switch tube in the delayed on-off module is the transistor V2, and the energy discharge module is the diode D4.

[0032] Before the power switch tube VT2 is turned on, the auxiliary switch tube V2 is turned on first, and the resonant capacitor C2 and the resonant inductor L3 form a resonant circuit. During the resonance process, the current of L3 increases and the voltage of C2 decreases until the voltage across C2 drops to zero. The reverse diode D2 of VT2 is turned on, clamping the voltage across C2 to zero, and the current of L3 remains unchanged. This state is maintained until VT2 is turned on and V2 is turned off. Since VT2 is turned on under zero voltage, there is no conduction loss. When VT2 is turned on, V2 is turned off, and the energy in L3 is transmitted to the load side through the diode D4. Its current decreases linearly, while the current in VT2 increases linearly until the current is equal to the current in L1, and the circuit is turned on normally.

[0033] After the power switch tube VT2 is turned off, the power supply U charges the capacitor C2, which greatly slows down the speed at which the voltage across VT2 increases, and effectively reduces the turn-off loss of the power switch tube VT2.

[0034] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0035] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0036] The disclosed embodiments are described above to enable any person skilled in the art to implement or use the present invention. Various modifications of these embodiments are obvious to those skilled in the art, and the general principles defined herein may also be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0037] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

[0038] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A switching circuit for a magnetic bearing power amplifier, characterized in that: The circuit comprises: a power switch tube, a delay on-off module, and an energy discharge module; The delayed on-off module is used to make the switch voltage of the power switch tube zero before it is turned on, and to slowly increase the switch voltage after it is turned off; An energy discharge module, used to discharge the energy in the delayed on-off module when the power switch tube is turned on; The delayed on-off module includes a resonance module and an auxiliary switch tube electrically connected to each other, wherein the resonance module generates resonance when the auxiliary switch tube is turned on, so that the switch voltage of the power switch tube is reduced in advance before the power switch tube is turned on, and the increase of the switch voltage of the power switch tube is delayed after the power switch tube is turned off; The resonance module includes a resonance capacitor and a resonance inductor; the resonance inductor is electrically connected to the auxiliary switch tube and then connected in parallel with the resonance capacitor; The auxiliary switch tube is a triode, which is turned on when the power switch tube is turned off, and is turned off when the power switch tube is turned on.

2. The circuit according to claim 1, characterized in that The energy discharge module includes a diode connected between the delay on-off module and a load.

3. The circuit according to claim 1, characterized in that The circuit also includes a pulse modulation module, which is electrically connected to the power switch tube and the delayed on-off module, and is used to provide a control level to the power switch tube and the delayed on-off module.

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