Bidirectional motor positive and negative rotation mutual exclusion circuit and household appliance with same

Abstract

The utility model particularly relates to a bidirectional motor positive and negative rotation mutual exclusion circuit and a household electrical appliance with the same, comprising a normally open relay K1, a normally open contact of which is connected in series with a motor power supply loop; a contact of the double-pole double-throw relay K2 is connected with the power supply and the motor so as to switch forward and reverse rotation directions; the output end of the single chip microcomputer U1 is respectively connected with a first triode Q1 and a second triode Q2, the first triode Q1 and the second triode Q2 are respectively connected with the control end of the normally open relay K1 and the control end of the double-pole double-throw relay K2, and the on-off of the normally open relay K1 and the switching of the double-pole double-throw relay K2 are controlled through the single chip microcomputer U1; and the switching ends of the motor M and the double-pole double-throw relay K2 are respectively connected with a directional excitation coil of the motor M. According to the circuit, through combination of the single-chip microcomputer U1, the first triode Q1 and the second triode Q2, switching or on-off of the normally open relay K1 and the switching double-pole double-throw relay K2 is controlled, and safety and reliability are enhanced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a bidirectional motor positive and negative rotation mutual exclusion circuit and household appliance with the circuit BACKGROUND

[0002] With the continuous progress and innovation of science and technology, motor control technology has been widely researched and applied, for example, the motor positive and negative rotation control circuit generally has the following circuit characteristics.

[0003] I. Main circuit design, power supply phase modulation structure: two contactors KM1 and KM2 are used to control the positive and negative rotation phase sequence: positive rotation loop: three-phase power supply is connected to the motor according to L1→U, L2→V and L3→W. Reverse loop: change the phase sequence of L1 and L3, that is, L3→U, L2→V and L1→W are connected to the motor. Short circuit protection: a fuse FU1 and a thermal relay FR are arranged in the main circuit, the former prevents short circuit, and the latter provides overload protection.

[0004] II. Control circuit design: double interlocking mechanism: contactor interlocking: the normally closed contact of contactor KM1 is connected in series in the coil loop of contactor KM2, and the normally closed contact of contactor KM2 is connected in series in the coil loop of contactor KM1, to ensure that both cannot be powered at the same time. Button interlocking: composite buttons SB2 and SB3 are used, and their normally closed contacts are connected into the control loop of the other party, to realize mechanical interlocking. Interlocking relay delay protection (prevent phase-to-phase short circuit): interlocking relay K is added in the control loop of contactor KM1 and contactor KM2, and the coil of K is controlled by the auxiliary contact of contactor KM1 or contactor KM2. The normally closed contact of K is connected in series in the loop of the other party contactor, and through the arc extinguishing delay release characteristics of the relay, it is ensured that the reverse contactor is allowed to close only after the arc is completely extinguished.

[0005] The above motor positive and negative rotation control circuit has the following four defects.

[0006] Defect One: Difficulty in Design and Commissioning: The existing motor forward and reverse control circuit contains multiple designs of main circuit and control circuit. The main circuit involves power phase modulation structure, which requires precise setting of two contactors KM1 and KM2 to control the forward and reverse phase sequence, and also needs to configure a fuse FU1 and a thermal relay FR for short circuit and overload protection. In terms of control circuit, the contactor interlock in double interlock mechanism, button interlock, and interlock relay delay protection, each link needs to be designed and connected carefully. This makes the design process of the entire circuit complex, requiring high professional knowledge and experience of the designer. During the debugging stage, due to the large number of circuit links, any small error can cause the entire circuit to malfunction, and the difficulty of troubleshooting is also increased accordingly. In addition, high maintenance cost: complex circuit means more electronic components and connection lines. With the increase of use time, the probability of failure of these components and lines will also increase. Once a component is damaged or a line is problematic, maintenance personnel need to spend a lot of time and effort to locate the fault point. Moreover, due to the complexity of the circuit, professional technicians and special tools may be required for the repair process, which undoubtedly increases the maintenance cost. At the same time, replacing the damaged components also needs to consider the compatibility and performance matching of the components, further increasing the difficulty and cost of maintenance.

[0007] Defect Two: Reliability Issues: Component Failure Risk: The circuit uses multiple contactors, relays, buttons, and other components, which are prone to wear, aging, and other problems during long-term use. For example, the contacts of the contactor will produce arc during frequent opening and closing, causing contact erosion and affecting normal operation. The coil of the relay may also heat up due to long-term energization, and even burn out. Once a component fails, the interlock mechanism of the entire circuit may fail, causing safety accidents. Poor environmental adaptability: The existing circuit design is sensitive to environmental conditions. In some harsh industrial environments, such as high temperature, humidity, and dust, the components in the circuit are easily affected. High temperature may cause component performance degradation, humid environment may cause line short circuit, and dust may accumulate on the surface of the components, affecting their heat dissipation and electrical performance. These environmental factors will reduce the reliability of the circuit and increase the probability of failure.

[0008] Defect Three: Consequences of Simultaneous Forward and Reverse Rotation of Motor: Mechanical Damage: When the motor rotates simultaneously in forward and reverse directions, the rotor of the motor will be subjected to two opposite torques, which will cause the mechanical structure of the motor to bear a large stress. Long-term in this state, the shaft, bearing and other components of the motor are prone to deformation, wear or even breakage, which seriously affects the service life of the motor.

[0009] Defect four, electrical damage: the motor simultaneously forward and reverse rotation can make the motor current increases dramatically, more than the rated current of the motor. This can cause the motor winding heat, insulation damage, and even cause short circuit fault. Once the short circuit, not only will damage the motor itself, but also can affect the normal operation of the entire power system, causing greater losses.

[0010] In order to overcome these shortcomings, the present application proposes a new type of bidirectional motor forward and reverse exclusion circuit, aiming at solving the above problems, and promoting the further development of motor control technology. SUMMARY

[0011] The utility model discloses at least solve one of the technical problems existing in the prior art. For this purpose, one purpose of the utility model is to propose a bidirectional motor forward and reverse exclusion circuit and household appliance with the circuit, which can safely and reliably control the circuit design of motor forward and reverse rotation to meet the needs of household appliance control and other fields.

[0012] According to the utility model discloses a bidirectional motor forward and reverse exclusion circuit, comprising the following.

[0013] The normally open relay K1 is connected in series with the motor power supply loop.

[0014] The double-pole double-throw relay K2 is connected to the power supply and the motor to switch the forward and reverse directions.

[0015] The single-chip microcomputer U1 is connected to the first and second triodes Q1 and Q2, respectively. The first and second triodes Q1 and Q2 are connected to the control terminals of the normally open relay K1 and the double-pole double-throw relay K2, respectively. The normally open relay K1 is controlled by the single-chip microcomputer U1 to switch on and off, and the double-pole double-throw relay K2 is switched by the single-chip microcomputer U1. The normally open relay K1 needs to be disconnected before the forward and reverse switching.

[0016] The motor M is connected to the direction excitation coil of the motor M.

[0017] Further, the direction excitation coil of the motor M is divided into a clockwise magnetic coil CW and a counterclockwise excitation coil CCW. A first capacitor C1 is provided between the clockwise magnetic coil CW and the counterclockwise excitation coil CCW.

[0018] Further, a first diode D1 is connected in parallel between the 4th and 3rd pins of the normally open relay K1, and a second diode D2 is connected in parallel between the 4th and 3rd pins of the double-pole double-throw relay K2. The control terminals of the normally open relay K1 and the double-pole double-throw relay K2 are connected to the output terminals of the single-chip microcomputer U1, respectively.

[0019] Specific further, the 1 foot of the singlechip U1 is connected with +5V end, the +5V end is connected with electrolytic capacitor EC1, and the electrolytic capacitor EC1 is connected with the second capacitor C2 in parallel.

[0020] Specific further, the 2 foot of the singlechip U1 is connected with the third triode Q3, and the collector of the third triode Q3 is connected with the alarm SP1.

[0021] The utility model discloses a kind of household appliances, including control unit, the control unit includes the bidirectional motor positive and negative rotation mutual exclusion circuit of any one of the above technical solutions.

[0022] The beneficial effects of the utility model are: the circuit is combined by singlechip U1, first triode Q1 and second triode Q2, to control the switching or on-off of always-on relay K1 and switching double-pole double-throw relay K2, prevent the simultaneous connection of motor positive and negative rotation, enhance the safety of motor control, improve control reliability and realize simplified circuit, and singlechip U1, first triode Q1, second triode Q2, always-on relay K1 and switching double-pole double-throw relay K2 are installed on the same circuit board, to reduce the complexity and cost of circuit design, thereby reducing the size of overall circuit board;In addition, the circuit can be applied to various occasions requiring motor positive and negative rotation control, and has wide market value. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and / or additional aspects and advantages of the utility model will become apparent and more readily appreciated from the following description of the embodiments, with reference to the following drawings.

[0024] Figure 1 It is the circuit diagram of the utility model.

[0025] Figure 2 It is the control method logic diagram of the utility model. DETAILED DESCRIPTION

[0026] The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary, only for explaining the utility model, and cannot be understood as limiting the utility model.

[0027] The following refers to Figure 1 A bidirectional motor positive and negative rotation mutual exclusion circuit according to an embodiment of the utility model is described below, which comprises the following.

[0028] The always-on contact of always-on relay K1 is connected in series in motor power supply loop.

[0029] The contact of switching double-pole double-throw relay K2 is connected with power supply and motor to switch positive and negative rotation direction.

[0030] The single-chip microcomputer U1 is connected with the first triode Q1 and the second triode Q2 respectively, and the first triode Q1 and the second triode Q2 are connected to the control end of the normally open relay K1 and the double-pole double-throw relay K2 respectively. The normally open relay K1 and the double-pole double-throw relay K2 are controlled by the single-chip microcomputer U1. The normally open relay K1 needs to be disconnected before the forward and reverse switching.

[0031] The switching end of the double-pole double-throw relay K2 is connected to the direction excitation coil of the motor M.

[0032] The circuit is combined by the single-chip microcomputer U1, the first triode Q1 and the second triode Q2, so as to control the switching or on-off of the normally open relay K1 and the double-pole double-throw relay K2, prevent the motor from being connected at the same time of forward and reverse rotation, enhance the safety of motor control, improve the control reliability and simplify the circuit. The single-chip microcomputer U1, the first triode Q1, the second triode Q2, the normally open relay K1 and the double-pole double-throw relay K2 are installed on the same circuit board, so as to reduce the complexity and cost of circuit design, thereby reducing the size of the overall circuit board. In addition, the circuit can be applied to various occasions requiring motor forward and reverse rotation control, and has wide market value.

[0033] Main power control: the normally open relay K1 is directly connected in series in the motor main circuit as the motor power switch, and is responsible for the hard cut-off of the motor start and stop to avoid short circuit when switching direction.

[0034] Direction switching: the double-pole double-throw relay K2 changes the direction (CW / CCW) of the current flowing through the motor excitation coil by cross-positioning of two groups of contacts, so as to realize the forward and reverse rotation control. The contact capacity needs to be higher than 20% of the maximum working current of the motor.

[0035] Single-chip microcomputer U1 cooperative control: time sequence priority design: the single-chip microcomputer U1 controls the work of the normally open relay K1 and the double-pole double-throw relay K2 through the first triode Q1 and the second triode Q2 respectively. The control logic forcibly requires the operation sequence of the normally open relay K1 being disconnected→ the double-pole double-throw relay K2 being switched→ the normally open relay K1 being closed. The interlocking is realized by the program of the single-chip microcomputer U1, so as to ensure that the normally open relay K1 is prohibited in the attracted state, and the double-pole double-throw relay K2 switching signal output is prohibited.

[0036] State feedback loop: the physical state of the normally open relay K1 and the double-pole double-throw relay K2 is confirmed in real time by detecting the auxiliary contact or coil voltage of the normally open relay K1, and double check is formed with the program instruction.

[0037] The model of the single-chip microcomputer U1 is SC92F7411. The timing control of the single-chip microcomputer U1 is optimized in the following manners: 1. adaptive delay: automatically adjusting switching interval (5-100 ms programmable) according to ambient temperature, prolonging to 150 ms in low temperature environment to ensure that the mechanical mechanism is in place; 2. contact bounce elimination: using single-chip microcomputer U1 pre-recorded software debouncing algorithm, confirming switching completion only after 5 consecutive samples of the state of the double-pole double-throw relay K2 are consistent; 3. fault self-check: performing a self-check sequence upon power-up: open-close test of the normally open relay K1 → forward-reverse switching test of the double-pole double-throw relay K2 → alarm SP1 sounding test.

[0038] Further, the direction excitation coils of the motor M are divided into a clockwise excitation coil CW and a counterclockwise excitation coil CCW, and a first capacitor C1 is arranged between the clockwise excitation coil CW and the counterclockwise excitation coil CCW. The first capacitor C1 is connected in parallel between the clockwise excitation coil CW and the counterclockwise excitation coil CCW, absorbs the transient voltage (typical value 0.1 μF / 1 kV) generated during commutation, and plays a high-frequency filtering role.

[0039] Forward rotation starting phase: instruction receiving: after the single-chip microcomputer U1 receives a forward rotation signal, it first detects whether the K1 state is open (initial start can be directly executed); direction presetting: outputting a low level to the base of the second triode Q2 → the double-pole double-throw relay K2 coil is powered on → the contacts are switched to the clockwise excitation coil CW (at this time, the motor does not move because K1 is not closed).

[0040] Further, the fourth pin and the third pin of the normally open relay K1 are connected in parallel with a first diode D1, the fourth pin and the third pin of the double-pole double-throw relay K2 are connected in parallel with a second diode D2, and the control ends of the normally open relay K1 and the double-pole double-throw relay K2 are connected to the output end of the single-chip microcomputer U1. When the power is turned on, a low level is output to the base of the first triode Q1 after a delay of 5 ms to confirm that the double-pole double-throw relay K2 has completed the action, and the normally open relay K1 is attracted to turn on the main circuit. In addition, the internal timer of the single-chip microcomputer U1 is started to monitor the state of the normally open relay K1.

[0041] When the reverse rotation instruction is received, the single-chip microcomputer U1 immediately cuts off the driving signal of the first triode Q1, and the normally open relay K1 is de-energized and opened (the main circuit is powered off).

[0042] Arc elimination: the first diode D1 connected in parallel with the contacts of the normally open relay K1 quickly discharges the coil energy, shortening the contact separation time; in addition, direction switching: after the normally open relay K1 is completely opened (about 10 ms mechanical delay), the double-pole double-throw relay K2 is driven to switch to the counterclockwise excitation coil CCW.

[0043] State confirmation: through detecting the double-pole double-throw relay K2 contact feedback signal or monitoring the coil current, the switching is confirmed to be in place; Restart power supply: drive the normally open relay K1 to close again, and reset the timer of the single-chip microcomputer U1.

[0044] In addition, the first diode D1 and the second diode D2 connected in parallel with the normally open relay K1 and the double-pole double-throw relay K2 respectively provide a freewheeling path, limit the back electromotive force at the time of turning off within 0.7V, prevent the first triode Q1 and the second triode Q2 from being broken down, and play a role in contact protection.

[0045] Specifically further, the 1 pin of the single-chip microcomputer U1 is connected with a +5V terminal, the +5V terminal is connected with an electrolytic capacitor EC1, and the electrolytic capacitor EC1 is connected in parallel with a second capacitor C2. The electrolytic capacitor EC1 and the second capacitor C2 constitute a π-type filter, eliminate the interference of relay action on the power supply of the single-chip microcomputer, and play a role in power supply purification.

[0046] Specifically further, the 2 pin of the single-chip microcomputer U1 is connected with a third triode Q3, and the collector of the third triode Q3 is connected with an alarm SP1. The abnormal processing mechanism of the circuit is as follows: one, switching conflict protection: if the single-chip microcomputer U1 detects that the normally open relay K1 is not disconnected when receiving the switching instruction, the single-chip microcomputer U1 immediately triggers the reset and turns on the third triode Q3 to start the alarm SP1 to give a warning; two, overcurrent protection: the single-chip microcomputer U1 monitors the main loop current through a sampling resistor, and forcibly disconnects the normally open relay K1 when the current exceeds the set value (such as 150% of the rated current); three, locked-rotor protection: combined with the running time and the Hall sensor feedback (if configured), the motor M is identified after locked-rotor and emergency shutdown is performed.

[0047] The utility model discloses a kind of household appliances, including control unit, the control unit uses the bidirectional motor forward and reverse rotation mutual exclusion circuit of above-mentioned. For example, the circuit is applied to the dehydration bucket control of household washing machine, wherein, load characteristic: inertia load needs to be alternately operated to prevent winding by forward and reverse rotation;Parameter setting: single forward rotation longest 30 seconds, timeout triggers alarm SP1 and sends fault code to display panel;Safety enhancement: increase door cover interlock switch, realize hardware level forced power-off in series in normally open relay K1 control circuit.

[0048] For example: a kind of industrial automation equipment, including drive unit, drive unit uses the bidirectional motor forward and reverse rotation mutual exclusion circuit of above-mentioned. For example, the circuit is applied to industrial conveying belt deviation rectification system, wherein high-frequency switching requirement: set minimum switching interval 200ms, meet the demand of 300 times fine adjustment per minute;Redundant design: parallel standby relay group, when detecting that contact resistance is out of tolerance (>50mΩ), automatically switch;Communication interface: feedback real-time state (current value, switching times, cumulative running time) through RS485 communication interface.

[0049] In standby state, the single-chip microcomputer U1 enters sleep mode (only the timing wake-up function is reserved), and the system standby power consumption is reduced from 20 mA to 50 mu A; the PWM soft start technology is adopted: the normally open relay K1 is attracted for 100 ms, and the power supply is provided with 80% duty cycle, so as to reduce the starting impact current; the intelligent diagnosis system is established: the relay life prediction model is established, the remaining life is estimated according to the switching times of the double-pole double-throw relay K2 and the power-on time of the normally open relay K1; when the switching time of the double-pole double-throw relay K2 exceeds 20% of the initial value, it is determined that the mechanical mechanism is worn and early warning is given; the multi-machine cooperative control is realized: through the cascade control interface, the synchronous forward and reverse rotation operation of multiple motors is realized, the timing error is controlled within ±1 ms, the hardware interlocking signal line is added, and the conflict action between the associated equipment is ensured.

[0050] As shown in Figure 2 The control method of the bidirectional motor forward and reverse rotation mutual exclusion circuit comprises the following steps.

[0051] When the forward rotation instruction is received, the single-chip microcomputer U1 controls the double-pole double-throw relay K2 to switch to the forward rotation position and then attracts the normally open relay K1.

[0052] When the reverse rotation instruction is received, the single-chip microcomputer U1 first disconnects the normally open relay K1, then switches the double-pole double-throw relay K2 to the reverse rotation position, and then attracts the normally open relay K1.

[0053] The state of the normally open relay K1 is detected in real time, and the double-pole double-throw relay K2 is prohibited from switching when the normally open relay K1 is not disconnected.

[0054] The 5-100 ms delay is set between the disconnection of the normally open relay K1 and the switching of the double-pole double-throw relay K2, and the contact state is detected after the double-pole double-throw relay K2 is switched, and then the normally open relay K1 is attracted.

[0055] The single-chip microcomputer U1 records the motor running time, and when the single forward / reverse rotation is timed out, the normally open relay K1 is automatically disconnected and the alarm SP1 is alarmed.

[0056] Although the embodiments of the utility model have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the utility model, and the scope of the utility model is defined by the claims and their equivalents.

Claims

1. A bidirectional motor forward-reverse commutation circuit, characterized by: The utility model relates to a bidirectional motor positive and negative rotation mutual exclusion circuit, comprising: a normally open relay K1, whose normally open contact is connected in series in the motor power supply loop; a double-pole double-throw relay K2, whose contact connects the power supply and the motor to switch the positive and negative rotation directions; a single-chip microcomputer U1, whose output end is connected with a first triode Q1 and a second triode Q2 respectively, and the first triode Q1 and the second triode Q2 are connected to the control end of the normally open relay K1 and the double-pole double-throw relay K2 respectively, the normally open relay K1 is controlled to be on and off and the double-pole double-throw relay K2 is controlled to be switched by the single-chip microcomputer U1, and the normally open relay K1 needs to be disconnected before the positive and negative rotation directions are switched; a motor M, whose direction excitation coil is connected to the switching end of the double-pole double-throw relay K2.

2. The bidirectional motor forward-reverse commutation circuit of claim 1, wherein: The direction excitation coil of the motor M is divided into a clockwise excitation coil CW and a counterclockwise excitation coil CCW, and a first capacitor C1 is arranged between the clockwise excitation coil CW and the counterclockwise excitation coil CCW.

3. The bidirectional motor forward-reverse commutation circuit of claim 1, wherein: A first diode D1 is connected in parallel between the 4th pin and the 3rd pin of the normally open relay K1, a second diode D2 is connected in parallel between the 4th pin and the 3rd pin of the double-pole double-throw relay K2, and the control end of the normally open relay K1 and the double-pole double-throw relay K2 is connected to the output end of the single-chip microcomputer U1 respectively.

4. The bidirectional motor forward-reverse commutation circuit of claim 1, wherein: The 1st pin of the single-chip microcomputer U1 is connected with a +5V terminal, the +5V terminal is connected with an electrolytic capacitor EC1, and the electrolytic capacitor EC1 is connected in parallel with a second capacitor C2.

5. The bidirectional motor forward-reverse commutation circuit of claim 1, wherein: The 2nd pin of the single-chip microcomputer U1 is connected with a third triode Q3, and the collector of the third triode Q3 is connected with a siren SP1.

6. A domestic appliance comprising a control unit, characterized in that: The control unit comprises the bidirectional motor positive and negative rotation mutual exclusion circuit according to any one of claims 1 to 5.

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