Series motor control circuit and method

Abstract

The present invention discloses a series-excited motor control circuit and method, belonging to the field of motor control technology. The control circuit includes a control circuit, which includes a drive circuit and a brake circuit. The control circuit includes a power supply, a switch group, an armature, an excitation winding, and a brake resistor. The armature and excitation winding constitute a motor. The switch group includes switches KV1, KV2, KV3, KV4, KV5, and KV6. The armature includes terminals ZH1 and ZH2. The excitation winding includes terminals D3 and D4. The brake resistor includes terminals RX1 and RX2. The upper end of switch KV1 is connected to the upper end of switch KV2, and both are connected to the positive pole of the power supply. The present invention actively controls the rapid switching of the power tube conduction state during the braking phase, reversely connecting the excitation winding to the brake circuit, and forming energy-consuming braking. This reduces the impact of inertial shock caused by excessive motor speed and improves the stability of the entire control system.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a series-excited motor control circuit and method. Background Art

[0002] A series-wound motor uses an armature winding connected in series with the field winding. Under normal operating conditions, the direction of the excitation current and the armature current remain consistent, ensuring that the armature's magnetic flux and current always align. When the power supply polarity reverses, the armature's magnetic flux and current reverse simultaneously, while the direction of the electromagnetic torque remains unchanged. This characteristic makes the series-wound armature compatible with both AC and DC power supplies. Furthermore, series-wound motors offer high starting torque and excellent overload capacity, along with a simple structure and low cost. Therefore, they are widely used in applications requiring load startup and frequent overload operations, particularly in applications such as driving switches or vehicle towing in high-voltage power distribution systems.

[0003] Currently, the starting, forward / reverse rotation, and braking control of DC series-wound motors primarily rely on relay logic circuits composed of components such as relays and contactors. This control method is complex in structure, hindering the miniaturization and intelligent integration of equipment, and contact wear seriously affects the mechanical life of the device. To this end, Chinese invention patent CN114268252 discloses a series-wound DC motor controller without mechanical contactors. This controller replaces traditional contactors with semiconductors to form a full-bridge circuit, making the motor torque and speed adjustable and improving the reliability of the motor control system. Chinese invention patent CN109546906 discloses a DC series-wound motor control system and method. This controller uses power electronic devices to achieve contactless smooth commutation and high-speed magnetic field weakening control of the DC series-wound motor, solving the problem of energy loss.

[0004] The above patents address some of the issues with series-wound motors, but they fail to address motor braking. In applications such as switching, if the motor is not braked promptly after the action is completed, it may be damaged due to excessive speed, resulting in inertial shock, damaging the transmission system or load equipment, and affecting the stable operation of the entire control system. Therefore, it is particularly critical to quickly brake the motor after the action is completed. Based on this, a series-wound motor control circuit and method are now proposed. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems existing in the prior art and to propose a series motor control circuit and method.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A series motor control circuit and method, comprising a control circuit, wherein the control circuit comprises a drive circuit and a brake circuit;

[0008] The control circuit includes a power supply, a switch group, an armature, an excitation winding and a brake resistor. The armature and the excitation winding constitute a motor. The switch group includes a switch KV1, a switch KV2, a switch KV3, a switch KV4, a switch KV5 and a switch KV6. The armature includes terminals ZH1 and ZH2. The excitation winding includes terminals D3 and D4. The brake resistor includes terminals RX1 and RX2.

[0009] The upper end of the switch KV1 is connected to the upper end of the switch KV2 and is connected to the positive electrode of the power supply.

[0010] The lower end of the switch KV1 is connected to the node OUT1, and the node OUT1 is connected to the upper end of the switch KV3 and the upper end of the switch KV6 respectively;

[0011] The lower end of the switch KV2 is connected to the armature terminal ZH2, while the terminal ZH2 is connected to the upper end of the switch KV4 and the upper end of the switch KV5 respectively;

[0012] The other terminal ZH1 of the armature is led out as a node OUT2;

[0013] The lower end of the switch KV5 is connected to the lower end of the switch KV6 and is commonly connected to the node RX;

[0014] The lower end of the switch KV3 is connected to the lower end of the switch KV4 and is commonly connected to the terminal D3 of the excitation winding;

[0015] The other terminal D4 of the excitation winding is connected to the negative pole of the power supply;

[0016] The braking resistor has two connection modes in the control circuit: connection mode 1 and connection mode 2.

[0017] As a preferred solution, the braking resistor is connected in a first manner: one terminal RX2 of the braking resistor is connected to the terminal D4 of the excitation winding, the other terminal RX1 of the braking resistor is connected to the node RX, and the node OUT1 is connected to the node OUT2.

[0018] As a preferred solution, the second connection mode of the braking resistor is: the terminal RX1 of the braking resistor is connected to the node OUT1, the other terminal RX2 of the braking resistor is connected to the node OUT2, and the node RX is connected to the terminal D4.

[0019] As a preferred solution, the switch KV1, the switch KV2, the switch KV3 and the switch KV4 form an H-bridge circuit to control the direction of the armature current to achieve forward and reverse rotation of the motor.

[0020] As a preferred solution, based on the first connection method of the braking resistor:

[0021] When the motor rotates forward, the drive circuit is composed of the power supply, switch KV1, armature, switch KV4 and excitation winding; the brake circuit is composed of the armature, switch KV5, brake resistor, excitation winding and switch KV3;

[0022] When the motor reverses, the drive circuit is composed of the power supply, switch KV2, armature, switch KV3 and excitation winding; the brake circuit is composed of the armature, switch KV6, brake resistor, excitation winding and switch KV4.

[0023] As a preferred solution, based on the second connection method of the braking resistor:

[0024] When the motor rotates forward, the drive circuit is composed of the power supply, switch KV1, brake resistor, armature, switch KV4 and excitation winding; the brake circuit is composed of the armature, switch KV5, excitation winding, switch KV3 and brake resistor;

[0025] When the motor reverses, the drive circuit is composed of the power supply, switch KV2, armature, brake resistor, switch KV3 and excitation winding; the brake circuit is composed of the armature, brake resistor, switch KV6, excitation winding and switch KV4.

[0026] A series motor control method comprises the following steps:

[0027] S1, the drive circuit starts working;

[0028] S2: The motor action is completed and a stop command is issued;

[0029] S3, the brake circuit starts working;

[0030] S4, the motor stops running and waits for the next action;

[0031] Specifically include:

[0032] The driving circuit connection mode includes a driving circuit connection mode 1 and a driving circuit connection mode 2, and the braking circuit connection mode includes a braking circuit connection mode 1 and a braking circuit connection mode 2;

[0033] The motor action includes two working modes: motor forward rotation and motor reverse rotation;

[0034] The braking circuit includes two working modes: motor forward braking and motor reverse braking.

[0035] As a preferred solution, based on the connection mode 1 of the braking resistor;

[0036] The drive circuit operates in two modes: forward rotation and reverse rotation.

[0037] When the motor rotates forward: the switch KV1 and the switch KV4 are turned on, and the current starts from the positive electrode of the power supply, flows through the switch KV1, the armature, the switch KV4 and the excitation winding in sequence, and returns to the negative electrode of the power supply;

[0038] When the motor is reversed: the switches KV2 and KV3 are turned on, and the current starts from the positive electrode of the power supply, flows through the switch KV2, the armature, the switch KV3 and the excitation winding in sequence, and returns to the negative electrode of the power supply;

[0039] The brake circuit operates in two modes: forward rotation and reverse rotation.

[0040] When the motor rotates forward: the brake circuit first closes switch KV1 and switch KV4, then opens switch KV5 and switch KV3. The current starts from the armature, flows through switch KV5, the brake resistor, the excitation winding and switch KV3 in sequence, and then returns to the armature. Finally, after the motor stops, switch KV5 and switch KV3 are closed, waiting for the next action.

[0041] When the motor reverses: the brake circuit first closes switch KV2 and switch KV3, and then opens switch KV6 and switch KV4. The current starts from the armature, flows through switch KV6, the brake resistor, the excitation winding and switch KV4 in sequence, and returns to the armature. Finally, after the motor stops, switch KV6 and switch KV4 are closed, waiting for the next action.

[0042] As a preferred solution, based on the second connection method of the braking resistor;

[0043] The drive circuit operates in two modes: forward rotation and reverse rotation.

[0044] When the motor rotates forward: the switch KV1 and the switch KV4 are turned on, and the current starts from the positive electrode of the power supply, flows through the switch KV1, the braking resistor, the armature, the switch KV4 and the excitation winding in sequence, and returns to the negative electrode of the power supply;

[0045] When the motor is reversed: the switch KV2 and the switch KV3 are turned on, and the current starts from the positive electrode of the power supply, flows through the switch KV2, the armature, the braking resistor, the switch KV3 and the excitation winding in sequence, and returns to the negative electrode of the power supply;

[0046] The brake circuit operates in two modes: forward rotation and reverse rotation.

[0047] When the motor rotates forward: the brake circuit first closes switch KV1 and switch KV4, then opens switch KV5 and switch KV3. The current starts from the armature, flows through switch KV5, the excitation winding, switch KV3 and the brake resistor in sequence, and returns to the armature. Finally, after the motor stops, switch KV5 and switch KV3 are closed, waiting for the next action.

[0048] When the motor reverses: the brake circuit first closes switch KV2 and switch KV3, and then opens switch KV6 and switch KV4. The current starts from the armature, flows through the brake resistor, switch KV6, excitation winding and switch KV4 in sequence, and returns to the armature. Finally, after the motor stops, switch KV6 and switch KV4 are closed, waiting for the next action.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] The present invention actively controls the rapid switching of the power tube conduction state during the braking phase, reversely connecting the excitation winding to the braking circuit to form dynamic braking, reducing the impact of inertial shock caused by excessive motor speed and improving the stability of the entire control system. In addition, it has the following beneficial effects:

[0051] 1. The magnetic field is attenuated by reversely energizing the excitation winding, solving the problem of brake failure caused by residual magnetism after the series-excited armature is powered off;

[0052] 2. The braking torque is actively established by utilizing the back electromotive force energy inside the armature, thus avoiding the speed overshoot caused by electromagnetic inertia;

[0053] 3. Through dynamic reconstruction of the control circuit, the braking response time is shortened to milliseconds, significantly superior to the delay characteristics of traditional mechanical brakes;

[0054] 4. The braking circuit and forward and reverse control share some power devices, reducing device selection costs and drive circuit complexity;

[0055] 5. Four-quadrant operation is achieved through H-bridge topology reconstruction, eliminating the design of independent braking contactors and reducing the system size. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a circuit diagram of a series motor control circuit proposed by the present invention;

[0057] Figure 2 This is a series motor control circuit diagram with a braking resistor connected in series in the braking circuit;

[0058] Figure 3 This is the current flow diagram of the motor forward drive circuit;

[0059] Figure 4 This is the current flow diagram of the motor forward braking circuit;

[0060] Figure 5 This is the current flow diagram of the motor reverse drive circuit;

[0061] Figure 6 This is the current flow diagram of the motor reversing brake circuit;

[0062] Figure 7 This is a series motor control circuit diagram with a braking resistor connected in series in the drive circuit;

[0063] Figure 8 This is the current flow diagram of the motor forward drive circuit;

[0064] Figure 9 This is the current flow diagram of the motor forward braking circuit;

[0065] Figure 10 This is the current flow diagram of the motor reverse drive circuit;

[0066] Figure 11 This is the current flow diagram of the motor reverse braking circuit. DETAILED DESCRIPTION

[0067] 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 only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0068] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0069] Example 1

[0070] Reference Figures 1 to 11 , including a control circuit, the control circuit includes a drive circuit and a brake circuit;

[0071] The control circuit includes a power supply, a switch group, an armature, an excitation winding, and a brake resistor. The armature and the excitation winding constitute a motor. The switch group includes switches KV1, KV2, KV3, KV4, KV5, and KV6. The armature includes terminals ZH1 and ZH2. The excitation winding includes terminals D3 and D4. The brake resistor includes terminals RX1 and RX2.

[0072] The upper end of the switch KV1 is connected to the upper end of the switch KV2 and connected to the positive pole of the power supply;

[0073] The lower end of the switch KV1 is connected to the node OUT1, and the node OUT1 is connected to the upper end of the switch KV3 and the upper end of the switch KV6;

[0074] The lower end of the switch KV2 is connected to the armature terminal ZH2, while the terminal ZH2 is connected to the upper end of the switch KV4 and the upper end of the switch KV5 respectively;

[0075] The other terminal ZH1 of the armature is led out as node OUT2;

[0076] The lower end of the switch KV5 is connected to the lower end of the switch KV6 and connected to the node RX.

[0077] The lower end of the switch KV3 is connected to the lower end of the switch KV4 and is commonly connected to the terminal D3 of the excitation winding;

[0078] The other terminal D4 of the excitation winding is connected to the negative pole of the power supply.

[0079] There are two ways to connect the brake resistor in the circuit:

[0080] Braking resistor connection method 1: One terminal RX2 of the braking resistor is connected to one terminal D4 of the excitation winding, the other terminal RX1 of the braking resistor is connected to RX, and OUT1 is connected to OUT2;

[0081] The second connection method of the braking resistor is that the braking resistor is connected in series with the armature, that is, one terminal RX1 of the braking resistor is connected to OUT1, the other terminal RX2 of the braking resistor is connected to OUT2, and RX is connected to D4.

[0082] Switch KV1, switch KV2, switch KV3 and switch KV4 form an H-bridge circuit to control the direction of the armature current and realize forward and reverse rotation of the motor.

[0083] Switches include IGBTs, MOS tubes, thyristors and other functionally equivalent electronic power devices.

[0084] The circuit includes a drive circuit and a brake circuit; the drive circuit and the brake circuit are different according to different connection methods of the brake resistor in the circuit.

[0085] Based on the connection method 1 of the braking resistor:

[0086] When the motor rotates forward, the drive circuit is composed of the power supply, switch KV1, armature, switch KV4, and excitation winding; the brake circuit is composed of the armature, switch KV5, brake resistor, excitation winding, and switch KV3;

[0087] When the motor reverses, the drive circuit consists of the power supply, switch KV2, armature, switch KV3, and excitation winding; the brake circuit consists of the armature, switch KV6, brake resistor, excitation winding, and switch KV4.

[0088] Based on the second connection method of the brake resistor:

[0089] When the motor rotates forward, the drive circuit is composed of the power supply, switch KV1, brake resistor, armature, switch KV4, and excitation winding; the brake circuit is composed of the armature, switch KV5, excitation winding, switch KV3, and brake resistor;

[0090] When the motor reverses, the drive circuit consists of the power supply, switch KV2, armature, braking resistor, switch KV3, and excitation winding; the brake circuit consists of the armature, braking resistor, switch KV6, excitation winding, and switch KV4.

[0091] A series motor control circuit has the following steps:

[0092] Step 1: The drive circuit starts working;

[0093] Step 2: The motor action is completed and a stop command is issued;

[0094] Step 3: The brake circuit starts working;

[0095] Step 4: The motor stops and waits for the next action.

[0096] There are two connection methods for the drive circuit, circuit connection method 1 and circuit connection method 2.

[0097] There are two connection methods for the brake circuit, circuit connection method 1 and circuit connection method 2.

[0098] The drive circuit starts working in two working modes: motor forward rotation and motor reverse rotation; the brake circuit has two modes: motor forward rotation and motor reverse rotation.

[0099] Based on the circuit connection method 1, when the drive circuit is working, the motor rotates forward and reverse;

[0100] When the motor rotates forward: switch KV1 and switch KV4 are turned on, the current starts from the positive pole of the power supply, flows through switch KV1, armature, switch KV4 and excitation winding in sequence, and returns to the negative pole of the power supply;

[0101] When the motor reverses: switch KV2 and switch KV3 are turned on, the current starts from the positive pole of the power supply, flows through switch KV2, armature, switch KV3 and excitation winding in sequence, and returns to the negative pole of the power supply.

[0102] Based on the second circuit connection method, the drive circuit has the motor forward and reverse rotation when working;

[0103] When the motor rotates forward: switch KV1 and switch KV4 are turned on, and the current starts from the positive pole of the power supply, flows through switch KV1, the braking resistor, the armature, switch KV4 and the excitation winding in sequence, and returns to the negative pole of the power supply;

[0104] When the motor reverses: switch KV2 and switch KV3 are turned on, the current starts from the positive pole of the power supply, flows through switch KV2, armature, braking resistor, switch KV3 and excitation winding in sequence, and returns to the negative pole of the power supply.

[0105] Based on the circuit connection method 1, the brake circuit has the motor forward and the motor reverse;

[0106] When the motor rotates forward: the brake circuit first closes switch KV1 and switch KV4, then opens switch KV5 and switch KV3. The current starts from the armature, flows through switch KV5, the brake resistor, the excitation winding and switch KV3 in sequence, and then returns to the armature. Finally, after the motor stops, switch KV5 and switch KV3 are closed, waiting for the next action.

[0107] When the motor reverses: the brake circuit first closes switch KV2 and switch KV3, then opens switch KV6 and switch KV4. The current starts from the armature, flows through switch KV6, the brake resistor, the excitation winding and switch KV4 in sequence and returns to the armature. Finally, after the motor stops, switch KV6 and switch KV4 are closed and wait for the next action.

[0108] Based on the second circuit connection method, the brake circuit has motor forward rotation and motor reverse rotation;

[0109] When the motor rotates forward: the brake circuit first closes switch KV1 and switch KV4, then opens switch KV5 and switch KV3. The current starts from the armature, flows through switch KV5, excitation winding, switch KV3 and brake resistor in sequence and returns to the armature. Finally, after the motor stops, switch KV5 and switch KV3 are closed and wait for the next action.

[0110] When the motor reverses: the brake circuit first closes switch KV2 and switch KV3, then opens switch KV6 and switch KV4. The current starts from the armature, flows through the brake resistor, switch KV6, excitation winding and switch KV4 in sequence and returns to the armature. Finally, after the motor stops, switch KV6 and switch KV4 are closed and wait for the next action.

[0111] The braking principle of the brake circuit is to use the kinetic energy of the motor after the motor power is disconnected to generate electromagnetic braking torque. After the power is disconnected, the brake circuit maintains the excitation current to prevent the magnetic field from rapidly decaying and the back EMF from decreasing, which would prevent the armature from operating as a generator. At the same time, at the moment of power failure, the armature inertia continues to rotate and cuts the magnetic field, generating back EMF. If the excitation current disappears, the back EMF drops sharply, and the armature current may surge due to the extremely low resistance, causing overcurrent damage.

[0112] During braking, the direction of the armature current is kept unchanged, and the circuit is quickly changed to change the direction of the current in the excitation coil and immediately connect it to the braking resistor. At this time, there is still a magnetic field in the motor, and the rotor continues to rotate due to inertia, so the motor becomes a generator, supplying power to the braking resistor. At this time, the direction of the electromagnetic torque is opposite to the direction of armature rotation, which acts as a brake until the kinetic energy stored in the motor is completely consumed by the loss of the braking resistor and the motor itself, and the motor stops rotating.

[0113] The method for judging the end of braking is that when the speed drops to 0, there is no relative motion between the rotor conductor and the magnetic field, the induced current disappears, and the motor stops. For application scenarios with low operation frequency, a fixed duration can be set. After the fixed duration has passed after the braking program is started, it is judged that the motor has stopped.

[0114] Example 2

[0115] A series motor control circuit, such as Figure 2 As shown, it includes a power supply, a switch, a motor and a brake resistor. The switches include switch KV1, switch KV2, switch KV3, switch KV4, switch KV5 and switch KV6;

[0116] The motor consists of an armature and a field winding;

[0117] The upper end of switch KV1 is connected to the upper end of switch KV2 and is also connected to the positive pole of the power supply;

[0118] The lower end of the switch KV1 is connected to the upper end of the switch KV3 and is connected to the armature terminal ZH1;

[0119] The lower end of switch KV1 is connected to the upper end of switch KV6 and is connected to armature terminal ZH1;

[0120] The lower end of the switch KV2 is connected to the upper end of the switch KV4 and is also connected to the armature terminal ZH2;

[0121] The lower end of the switch KV2 is connected to the upper end of the switch KV5 and is also connected to the armature terminal ZH2;

[0122] The lower end of the switch KV5 is connected to the lower end of the switch KV6 and is also connected to the interface RX;

[0123] The lower end of the switch KV3 is connected to the lower end of the switch KV4 and is also connected to a terminal D3 of the excitation winding;

[0124] The other terminal D4 of the excitation winding is connected to the negative pole of the power supply;

[0125] The interface RX is connected to one terminal RX1 of the braking resistor, and the other terminal Rx2 of the braking resistor is connected to the other terminal D4 of the excitation winding.

[0126] The motor control circuit is divided into a drive circuit and a brake circuit; the drive circuit drives the motor through power; the brake circuit stops the motor from running.

[0127] When the motor rotates forward, the drive circuit is composed of the power supply, switch KV1, armature, switch KV4, and excitation winding; the brake circuit is composed of the armature, switch KV5, brake resistor, excitation winding, and switch KV3;

[0128] When the motor reverses, the drive circuit is composed of the power supply, switch KV2, armature, switch KV3, and excitation winding; the brake circuit is composed of the armature, switch KV6, brake resistor, excitation winding, and switch KV3.

[0129] A series motor control method includes motor forward rotation and motor reverse rotation. The specific steps are as follows:

[0130] When the motor rotates forward, the drive circuit works, such as Figure 3 As shown, switches KV1 and KV4 are turned on, and the current starts from the positive pole of the power supply, flows through switch KV1, armature, switch KV4 and excitation winding in sequence, and returns to the negative pole of the power supply;

[0131] When the motor completes its rotation and issues a stop command, the brake circuit starts working. Figure 4 As shown, switch KV1 and switch KV4 are closed, and switch KV5 and switch KV3 are opened. The current starts from the armature, flows through switch KV5, the braking resistor, the excitation winding and switch KV3 in sequence, and returns to the armature; after the motor stops, switch KV5 and switch KV3 are closed, waiting for the next action.

[0132] When the motor reverses, the drive circuit works like Figure 5 As shown, switches KV2 and KV3 are turned on, and the current starts from the positive pole of the power supply, flows through switch KV2, armature, switch KV3 and the excitation winding shown in the figure, and returns to the negative pole of the power supply;

[0133] When the motor completes its rotation and issues a stop command, the brake circuit starts working. Figure 6As shown, switch KV2 and switch KV3 are closed, and switch KV6 and switch KV4 are opened. The current starts from the armature, flows through switch KV6, the braking resistor, the excitation winding and switch KV4 in sequence, and returns to the armature; after the motor stops, switch KV6 and switch KV4 are closed, waiting for the next action.

[0134] This embodiment places the braking resistor independently within the braking circuit, isolating it from the drive circuit. Therefore, during normal motor operation, the braking resistor does not participate in operation, generating no additional heat or impacting the motor's drive performance. This improves system energy efficiency and extends the life of the braking resistor. However, because the braking resistor is not connected to the drive circuit, it cannot limit the current at the moment of motor startup. Therefore, in certain applications sensitive to starting current, inrush current may not be effectively suppressed, adversely affecting components such as the motor's brushes.

[0135] Example 3

[0136] like Figure 7 As shown, a series motor control circuit includes a power supply, a switch, a motor and a brake resistor, wherein the switches include switch KV1, switch KV2, switch KV3, switch KV4, switch KV5 and switch KV6;

[0137] The motor consists of an armature and a field winding;

[0138] The upper end of switch KV1 is connected to the upper end of switch KV2 and is also connected to the positive pole of the power supply;

[0139] The lower end of switch KV1 is connected to the upper end of switch KV3 and is also connected to a terminal RX1 of the brake resistor;

[0140] The lower end of switch KV1 is connected to the upper end of switch KV6 and is also connected to a terminal RX1 of the brake resistor;

[0141] The other terminal RX2 of the brake resistor is connected to the first terminal ZH1 of the armature;

[0142] The lower end of the switch KV2 is connected to the upper end of the switch KV4 and to the other armature terminal ZH2;

[0143] The lower end of the switch KV2 is connected to the upper end of the switch KV5 and to the other armature terminal ZH2;

[0144] The lower end of the switch KV3 is connected to the lower end of the switch KV4 and is also connected to a terminal D3 of the excitation winding;

[0145] The lower end of the switch KV5 is connected to the lower end of the switch KV6 and is also connected to the interface RX;

[0146] The interface RX is connected to the other terminal D4 of the excitation winding and is also connected to the negative pole of the power supply.

[0147] The motor control circuit is divided into a drive circuit and a brake circuit; the drive circuit drives the motor through power; the brake circuit stops the motor from running.

[0148] When the motor rotates forward, the drive circuit is composed of the power supply, switch KV1, brake resistor, armature, switch KV4, and excitation winding; the brake circuit is composed of the armature, switch KV5, excitation winding, switch KV3, and brake resistor;

[0149] When the motor reverses, the drive circuit consists of the power supply, switch KV2, armature, braking resistor, switch KV3, and excitation winding; the brake circuit consists of the armature, braking resistor, switch KV6, excitation winding, and switch KV4.

[0150] A series motor control method includes motor forward rotation and motor reverse rotation. The specific steps are as follows:

[0151] When the motor rotates forward, the drive circuit works, such as Figure 8 As shown, switch KV1 and switch KV4 are turned on, and the current starts from the positive pole of the power supply, flows through switch KV1, the braking resistor, the armature, the switch KV4 and the excitation winding, and returns to the negative pole of the power supply;

[0152] When the motor completes its rotation and issues a stop command, the brake circuit starts working. Figure 9 As shown, switch KV1 and switch KV4 are closed, and switch KV5 and switch KV3 are opened. The current starts from the armature, flows through switch KV5, the excitation winding, switch KV3 and the braking resistor in sequence, and returns to the armature; after the motor stops, switch KV5 and switch KV3 are closed, waiting for the next action.

[0153] When the motor reverses, the drive circuit works, such as Figure 10 As shown, switch KV2 and switch KV3 are turned on, and the current starts from the positive pole of the power supply, flows through switch KV2, armature, brake resistor, switch KV3 and excitation winding in sequence, and returns to the negative pole of the power supply;

[0154] When the motor completes its rotation and issues a stop command, the brake circuit starts working. Figure 11 As shown, switch KV2 and switch KV3 are closed, and switch KV6 and switch KV4 are opened. The current starts from the armature, flows through the braking resistor, switch KV6, excitation winding and switch KV4 in sequence, and returns to the armature; after the motor stops, switch KV6 and switch KV4 are closed, waiting for the next action.

[0155] Connecting a braking resistor in series with the drive circuit allows it to participate in the operation of the drive circuit. During motor startup, the braking resistor effectively limits the starting current, protecting related equipment from damage and improving system reliability and safety. However, since the braking resistor continues to operate during motor operation, it can cause continuous heating, limiting the motor's maximum current, affecting its output speed and torque, and reducing its dynamic response and load capacity. Therefore, it is suitable for applications that require high starting current control but relatively low motor performance requirements.

[0156] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A series motor control circuit, characterized in that: comprising a control circuit, wherein the control circuit comprises a drive circuit and a brake circuit; The control circuit includes a power supply, a switch group, an armature, an excitation winding and a brake resistor. The armature and the excitation winding constitute a motor. The switch group includes a switch KV1, a switch KV2, a switch KV3, a switch KV4, a switch KV5 and a switch KV6. The armature includes terminals ZH1 and ZH2. The excitation winding includes terminals D3 and D4. The brake resistor includes terminals RX1 and RX2. The upper end of the switch KV1 is connected to the upper end of the switch KV2 and is connected to the positive electrode of the power supply. The lower end of the switch KV1 is connected to the node OUT1, and the node OUT1 is connected to the upper end of the switch KV3 and the upper end of the switch KV6 respectively; The lower end of the switch KV2 is connected to the armature terminal ZH2, while the terminal ZH2 is connected to the upper end of the switch KV4 and the upper end of the switch KV5 respectively; The other terminal ZH1 of the armature is led out as a node OUT2; The lower end of the switch KV5 is connected to the lower end of the switch KV6 and is commonly connected to the node RX; The lower end of the switch KV3 is connected to the lower end of the switch KV4 and is commonly connected to the terminal D3 of the excitation winding; The other terminal D4 of the excitation winding is connected to the negative pole of the power supply; The braking resistor has two connection modes in the control circuit: connection mode 1 and connection mode 2; Connection mode 1 of the braking resistor: one terminal RX2 of the braking resistor is connected to the terminal D4 of the excitation winding, the other terminal RX1 of the braking resistor is connected to the node RX, and the node OUT1 is connected to the node OUT2; The second connection mode of the braking resistor: a terminal RX1 of the braking resistor is connected to the node OUT1, another terminal RX2 of the braking resistor is connected to the node OUT2, and the node RX is connected to the terminal D4.

2. A series motor control circuit according to claim 1, characterized in that: The switch KV1, the switch KV2, the switch KV3 and the switch KV4 form an H-bridge circuit to control the direction of the armature current, thereby realizing forward and reverse rotation of the motor.

3. The series motor control circuit according to claim 1, characterized in that: Based on the connection method 1 of the braking resistor: When the motor rotates forward, the drive circuit is composed of the power supply, switch KV1, armature, switch KV4 and excitation winding; the brake circuit is composed of the armature, switch KV5, brake resistor, excitation winding and switch KV3; When the motor reverses, the drive circuit is composed of the power supply, switch KV2, armature, switch KV3 and excitation winding; the brake circuit is composed of the armature, switch KV6, brake resistor, excitation winding and switch KV4.

4. The series motor control circuit according to claim 1, characterized in that: Based on the second connection method of the brake resistor: When the motor rotates forward, the drive circuit is composed of the power supply, switch KV1, brake resistor, armature, switch KV4 and excitation winding; the brake circuit is composed of the armature, switch KV5, excitation winding, switch KV3 and brake resistor; When the motor reverses, the drive circuit is composed of a power supply, a switch KV2, an armature, a braking resistor, a switch KV3 and an excitation winding; the brake circuit is composed of an armature, a braking resistor, a switch KV6, an excitation winding and a switch KV4.

5. A series motor control method, characterized in that: The series motor control method is applied to the series motor control circuit according to any one of claims 1 to 4, comprising the following steps: S1, the drive circuit starts working; S2: The motor action is completed and a stop command is issued; S3, the brake circuit starts working; S4, the motor stops running and waits for the next action; Specifically include: The driving circuit connection mode includes a driving circuit connection mode 1 and a driving circuit connection mode 2, and the braking circuit connection mode includes a braking circuit connection mode 1 and a braking circuit connection mode 2; The motor action includes two working modes: motor forward rotation and motor reverse rotation; The braking circuit includes two working modes: motor forward braking and motor reverse braking.

6. A series motor control method according to claim 5, characterized in that: Based on the connection method 1 of the braking resistor; The drive circuit operates in two modes: forward rotation and reverse rotation. When the motor rotates forward: the switch KV1 and the switch KV4 are turned on, and the current starts from the positive electrode of the power supply, flows through the switch KV1, the armature, the switch KV4 and the excitation winding in sequence, and returns to the negative electrode of the power supply; When the motor is reversed: the switches KV2 and KV3 are turned on, and the current starts from the positive electrode of the power supply, flows through the switch KV2, the armature, the switch KV3 and the excitation winding in sequence, and returns to the negative electrode of the power supply; The brake circuit operates in two modes: forward rotation and reverse rotation. When the motor rotates forward: the brake circuit first closes switch KV1 and switch KV4, then opens switch KV5 and switch KV3. The current starts from the armature, flows through switch KV5, the brake resistor, the excitation winding and switch KV3 in sequence, and then returns to the armature. Finally, after the motor stops, switch KV5 and switch KV3 are closed, waiting for the next action. When the motor reverses: the brake circuit first closes switch KV2 and switch KV3, and then opens switch KV6 and switch KV4. The current starts from the armature, flows through switch KV6, the brake resistor, the excitation winding and switch KV4 in sequence, and returns to the armature. Finally, after the motor stops, switch KV6 and switch KV4 are closed, waiting for the next action.

7. A series motor control method according to claim 5, characterized in that: Based on the second connection method of the braking resistor; The drive circuit operates in two modes: forward rotation and reverse rotation. When the motor rotates forward: the switch KV1 and the switch KV4 are turned on, and the current starts from the positive electrode of the power supply, flows through the switch KV1, the braking resistor, the armature, the switch KV4 and the excitation winding in sequence, and returns to the negative electrode of the power supply; When the motor is reversed: the switch KV2 and the switch KV3 are turned on, and the current starts from the positive electrode of the power supply, flows through the switch KV2, the armature, the braking resistor, the switch KV3 and the excitation winding in sequence, and returns to the negative electrode of the power supply; The brake circuit operates in two modes: forward rotation and reverse rotation. When the motor rotates forward: the brake circuit first closes switch KV1 and switch KV4, then opens switch KV5 and switch KV3. The current starts from the armature, flows through switch KV5, the excitation winding, switch KV3 and the brake resistor in sequence, and returns to the armature. Finally, after the motor stops, switch KV5 and switch KV3 are closed, waiting for the next action. When the motor reverses: the brake circuit first closes switch KV2 and switch KV3, and then opens switch KV6 and switch KV4. The current starts from the armature, flows through the brake resistor, switch KV6, excitation winding and switch KV4 in sequence, and returns to the armature. Finally, after the motor stops, switch KV6 and switch KV4 are closed, waiting for the next action.

Images