Harmonic suppression circuit of alternating-current high-voltage brushless tool

Abstract

The invention discloses a harmonic suppression circuit for an alternating-current high-voltage brushless tool. The harmonic suppression circuit comprises a rectifier bridge BD1, a transistor GT1, a transistor GT2, a resistor R16, a resistor R36, a resistor R38, a capacitor C10, a relay, a triode Q7, an optical coupler U5 and a capacitor Y2. The relay, the resistor R36 and the resistor R38 are sequentially connected in series, the transistor GT1 and the transistor GT2 are connected in series, a base electrode of the triode Q7 is connected to a power supply input end through the resistor R16, and a collector electrode of the triode Q7 is connected to a control end of the relay through the resistor R36; the input end of the optical coupler U5 is connected to the transistor GT1, and the output end of the optical coupler U5 is connected to the base electrode of the triode Q7. An alternating current power supply is rectified through a rectifier bridge BD1, alternating current is converted into direct current, and four diodes of the rectifier bridge are connected to the input end and the output end of the power supply respectively; and the rectified direct current is filtered through a capacitor C10 so as to smooth the voltage.

Description

Technical Field

[0001] The invention relates to the technical field of harmonic suppression circuits, in particular to an AC high-voltage brushless tool harmonic suppression circuit. Background Art

[0002] The two sets of stator windings of the brushless double-fed AC motor can be connected to the industrial frequency grid and the variable frequency power supply at the same time. It has the operating characteristics of synchronous motors and asynchronous motors. The required inverter capacity is small and the operation is reliable. Especially in the case of higher voltage levels, the low voltage of the variable frequency power supply can control the high voltage, and the energy saving effect is significant. Compared with the brushless double-fed motor, the advantages are: simpler structure, no brushes make the reliability stronger, and the control end can adjust the power factor. Under the corresponding control end power supply mode, the corresponding operation modes include: asynchronous operation mode, synchronous operation mode, subsynchronous mode and supersynchronous mode. Among them, subsynchronous and supersynchronous are collectively referred to as double-fed operation modes. The control end can control the operation mode of the motor, and its power only accounts for a part of the total power of the motor. It can absorb energy from the grid and return energy to the grid at the same time, which can effectively reduce the capacity of the speed control system. This makes the brushless double-fed motor have great application prospects in the speed control system.

[0003] The existing publication number CN111181470A discloses a method for suppressing harmonics of a brushless doubly-fed motor, which belongs to the technical field of brushless doubly-fed motors and includes the following steps: S1: three sets of windings with pole pairs of P1, P2 and P3 are used to form the stator winding of the motor, and a composite span arrangement is used between each set of windings; S2: the positive direction of the flux linkage, current and voltage is selected; S3: the rotor winding is transformed to the stator side through the turns ratio, the number of turns of the stator and rotor windings is equal, and the mutual inductance flux between each winding passes through the air gap; S4: the air gap magnetic field characteristics are analyzed to obtain the air gap magnetic field waveform; S5: the three sets of stator windings are adjusted by a four-quadrant frequency converter to obtain the harmonic magnetomotive force fluctuation amplitude; three sets of windings with adjustable spans are used to form the stator winding, and the spans between the power winding, the control winding and the pitch-adjusting winding and the spans between the coils of each winding are gradually shortened within a certain range so that the harmonic magnetic fields overlap with each other, the short-distance effect is increased, and the harmonic magnetomotive force intensity is reduced.

[0004] Although the existing technology reduces the intensity of harmonic magnetomotive force, the existing technology improves the stator winding of the motor but does not improve the circuit, so that the harmonic suppression effect needs to be further improved. For this reason, we propose an AC high-voltage brushless tool harmonic suppression circuit. Summary of the invention

[0005] The object of the present invention is to provide an AC high-voltage brushless tool harmonic suppression circuit to solve the problems in the prior art.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an AC high-voltage brushless tool harmonic suppression circuit, comprising a rectifier bridge BD1, a transistor GT1, a transistor GT2, a resistor R16, a resistor R36, a resistor R38, a capacitor C10, a relay Relay, a transistor Q7, an optical coupler U5 and a capacitor Y2; the relay Relay, the resistor R36 and the resistor R38 are connected in series in sequence, the transistor GT1 and the transistor GT2 are connected in series, the base of the transistor Q7 is connected to the power input end through the resistor R16, and the collector of the transistor Q7 is connected to the control end of the relay Relay through the resistor R36; the input end of the optical coupler U5 is connected to the transistor GT1, and the output end of the optical coupler U5 is connected to the base of the transistor Q7.

[0007] Preferably, the four diodes of the rectifier bridge BD1 are connected to four endpoints respectively, and two diodes of the rectifier bridge BD1 are connected to the live wire and the ground wire respectively; the output end of the rectifier bridge BD1 is connected to the capacitor C10.

[0008] Preferably, the optical coupler U5, the resistor R36 and the resistor R38 form a voltage stabilizing circuit.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: the AC power supply is rectified by a rectifier bridge BD1 to convert the AC power into DC power, and the four diodes of the rectifier bridge are respectively connected to the input and output ends of the power supply; the rectified DC power is filtered by a capacitor C10 to smooth the voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0011] Figure 1 It is a circuit diagram of the present invention. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention.

[0013] See also Figure 1In an embodiment of the present invention, an AC high-voltage brushless tool harmonic suppression circuit includes a rectifier bridge BD1, a transistor GT1, a transistor GT2, a resistor R16, a resistor R36, a resistor R38, a capacitor C10, a relay Relay, a transistor Q7, an optical coupler U5 and a capacitor Y2; the relay Relay, the resistor R36 and the resistor R38 are connected in series in sequence, the transistor GT1 and the transistor GT2 are connected in series, the base of the transistor Q7 is connected to the power input end through the resistor R16, the collector of the transistor Q7 is connected to the control end of the relay Relay through the resistor R36, the relay switches the on and off state of the circuit by controlling its coil voltage, and the relay is used to control a high-power load or isolate different circuit parts; the input end of the optical coupler U5 is connected to the transistor GT1, and the output end of the optical coupler U5 is connected to the base of the transistor Q7.

[0014] Preferably, the four diodes of the rectifier bridge BD1 are respectively connected to four endpoints, and two of the diodes of the rectifier bridge BD1 are respectively connected to the live wire and the ground wire; the output end of the rectifier bridge BD1 is connected to the capacitor C10, the AC power supply is rectified by a rectifier bridge BD1 to convert the AC power into DC power, and the four diodes of the rectifier bridge are respectively connected to the input and output ends of the power supply; the rectified DC power is filtered by the capacitor C10 to smooth the voltage.

[0015] Preferably, the optical coupler U5, resistor R36 and resistor R38 form a voltage stabilizing circuit, and the control end of the relay Relay is connected to a 5V power supply through the resistors R36 and R38; the control signal of the relay is provided by a transistor Q7 and an optical coupler U5.

[0016] The working principle of the present invention is: the AC power supply is rectified by a rectifier bridge BD1 to convert the AC power into DC power, and the four diodes of the rectifier bridge are respectively connected to the input and output ends of the power supply; the rectified DC power is filtered by a capacitor C10 to smooth the voltage.

[0017] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An AC high-voltage brushless tool harmonic suppression circuit, characterized in that: It includes a rectifier bridge BD1, a transistor GT1, a transistor GT2, a resistor R16, a resistor R36, a resistor R38, a capacitor C10, a relay Relay, a transistor Q7, an optical coupler U5 and a capacitor Y2; the relay Relay, the resistor R36 and the resistor R38 are connected in series in sequence, the transistor GT1 and the transistor GT2 are connected in series, the base of the transistor Q7 is connected to the power input end through the resistor R16, and the collector of the transistor Q7 is connected to the control end of the relay Relay through the resistor R36; the input end of the optical coupler U5 is connected to the transistor GT1, and the output end of the optical coupler U5 is connected to the base of the transistor Q7.

2. The harmonic suppression circuit of an AC high-voltage brushless tool according to claim 1, characterized in that: The four diodes of the rectifier bridge BD1 are connected to four endpoints respectively, and two diodes of the rectifier bridge BD1 are connected to the live wire and the ground wire respectively; the output end of the rectifier bridge BD1 is connected to the capacitor C10.

3. The harmonic suppression circuit of an AC high-voltage brushless tool according to claim 1, characterized in that: The optical coupler U5, the resistor R36 and the resistor R38 form a voltage stabilizing circuit.

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