Motor controller

Abstract

The utility model discloses a motor controller, which can restrain the bus voltage of the motor controller from being too high when a motor is reversely dragged. The motor controller comprises a driving circuit, an overvoltage detection circuit, an n-phase inverter circuit and n switching circuits, n = 2 or 3; the control end of the upper switching tube of each bridge arm in the n-phase inverter circuit is connected to a high-side driving signal output end of the driving circuit, the control end of the lower switching tube of each bridge arm is connected to the output end of a switching circuit, and the input end of each switching circuit is connected to a low-side driving signal output end of the driving circuit; when the overvoltage detection circuit detects that the bus voltage of the motor controller exceeds a preset value, the overvoltage detection circuit outputs a first control signal to each switching circuit and outputs a second control signal to the driving circuit; when the switching circuit receives the first control signal, the switching circuit enters a turn-off state and pulls up the voltage at the output end of the switching circuit; and the driving circuit enters a non-enabling state when receiving the second control signal.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, and more specifically to a motor controller. Background Art

[0002] The motor is an electrical device that uses the principle of electromagnetic induction to achieve mutual conversion between electrical energy and mechanical energy. When the motor is reverse-driven (reverse-driven means that the direction of the motor's output torque is opposite to the direction of the rotor's rotation, generally used in scenarios that require rapid braking or deceleration), the motor generates reverse electromotive force, converting mechanical energy into electrical energy, and charging the battery through the motor controller, such as Figure 1 shown.

[0003] However, when the battery is not connected to the circuit (for example, when the electric vehicle is being assembled or repaired, the battery is not connected to the electric vehicle) or is not storing electricity, the electric energy generated by the motor in reverse drag cannot be absorbed by the battery, resulting in a bus voltage U bus Rising sharply, when the bus voltage U bus When it is too high, it will affect the stability and safety of the motor controller. Utility Model Content

[0004] In view of this, the utility model provides a motor controller to suppress the bus voltage of the motor controller from being too high when the motor is reverse-driven.

[0005] A motor controller comprises: a driving circuit, an overvoltage detection circuit, an n-phase inverter circuit and n switch circuits; n is equal to 2 or 3;

[0006] The n-phase inverter circuit comprises n bridge arms, the output end of each bridge arm is respectively connected to one phase of the motor, the positive and negative poles of each bridge arm are respectively connected to the positive and negative poles of the busbar of the motor controller, and the negative pole of the busbar is grounded;

[0007] Each of the bridge arms has two upper and lower switch tubes, and the control end of the upper switch tube of each bridge arm is respectively connected to a high-side drive signal output terminal O of the drive circuit. H The control end of the lower switch tube of each bridge arm is connected to the output end of a switch circuit, and the input end of each switch circuit is connected to a low-side drive signal output end of the drive circuit. L ;

[0008] The overvoltage detection circuit is used to detect the bus voltage U of the motor controller bus When the preset value is exceeded, a first control signal is output to each switch circuit through the first output terminal O1 and a second control signal is output to the drive circuit through the second output terminal O2;

[0009] The switch circuit is used to enter a shutdown state and pull up the voltage of its own output terminal when receiving the first control signal, so that the lower switch tube connected to the output terminal of the switch circuit is always turned on;

[0010] The driving circuit is used to enter a disabled state upon receiving the second control signal, so that the upper switch tube of each bridge arm is normally off.

[0011] Optionally, the upper and lower switch tubes of each bridge arm are MOS tubes or IGBTs.

[0012] Optionally, the output signals of the first output terminal O1 and the second output terminal O2 are the same, and the first control signal and the second control signal are both high-level signals.

[0013] Optionally, the overvoltage detection circuit is a voltage comparator;

[0014] The input end of the voltage comparator is connected to the positive pole of the bus, and the reference end of the voltage comparator is used to receive a reference signal with a voltage value equal to the preset value; the voltage comparator compares the input end voltage with the reference end voltage, and when the input end voltage exceeds the reference end voltage, the output end of the voltage comparator flips from a low level to a high level.

[0015] Optionally, the circuit structures of the switch circuits are the same; the switch circuits include: a current limiting resistor R1, a switch tube Q5, a current limiting resistor R2, a switch tube Q6 and a current limiting resistor R3;

[0016] Wherein, the low side drive signal output terminal O L Connected to the output end of the switch tube Q6;

[0017] The input end of the switch tube Q6 is connected to the control end of the switch tube under the corresponding bridge arm in the n-phase inverter circuit;

[0018] The power supply voltage V1 is connected to the control end of the switch tube under the corresponding bridge arm through the current limiting resistor R3;

[0019] The power supply voltage V1 is connected to the input end of the switch tube Q5 through the current limiting resistor R1;

[0020] The input end of the switch tube Q5 is connected to the control end of the switch tube Q6 through the current limiting resistor R2;

[0021] The output end of the switch tube Q5 is grounded; the control end of the switch tube Q5 is connected to the first output end O1;

[0022] The power supply voltage V1 is higher than the power supply voltage of the motor controller.

[0023] Optionally, the switch circuit further includes: a boost circuit; an input end of the boost circuit is used to receive the power supply voltage of the motor controller, and an output end of the boost circuit is used to output the power supply voltage V1.

[0024] Optionally, the boost circuit is a charge pump.

[0025] Optionally, the switch circuit further includes: a clamping diode D1; the clamping diode D1 is connected between the control end and the output end of the switch tube Q6.

[0026] Optionally, the switch circuit further includes: a clamping diode D2; the clamping diode D2 is connected between the control end and the output end of the switch tube under the corresponding bridge arm.

[0027] Optionally, the switch tube Q5 and the switch tube Q6 are MOS tubes or IGBTs.

[0028] It can be seen from the above technical solution that the utility model can reverse the motor and cause the bus voltage U bus When the bus voltage U is too high, on the one hand, each lower switch tube is normally turned on by turning off each switch circuit, thereby realizing motor short-circuit braking / deceleration and effectively suppressing the bus voltage U bus On the other hand, it also controls the drive circuit to enter the non-enabled state, so that each upper switch tube is normally off, thereby avoiding the situation where the bridge arm is directly connected. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the utility model 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 utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of energy flow during reverse drag of a motor disclosed in the prior art;

[0031] Figure 2 A circuit schematic diagram of a motor controller disclosed in an embodiment of the utility model;

[0032] Figure 3 A circuit schematic diagram of an overvoltage detection circuit disclosed in an embodiment of the utility model;

[0033] Figure 4 A circuit schematic diagram of a switch circuit disclosed in an embodiment of the utility model;

[0034] Figure 5A circuit schematic diagram of another switch circuit disclosed in an embodiment of the utility model;

[0035] Figure 6 This is a circuit schematic diagram of another switching circuit disclosed in an embodiment of the utility model. DETAILED DESCRIPTION

[0036] For the purpose of reference and clarity, the technical terms, abbreviations or acronyms used below are summarized as follows:

[0037] MOSFET: Metal-Oxide-Semiconductor Field-Effect Transistor, metal oxide semiconductor field effect transistor, referred to as MOS tube;

[0038] IGBT: Insulated Gate Bipolar Transistor, insulated gate bipolar transistor;

[0039] Boost circuit: step-up chopper circuit.

[0040] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0041] See also Figure 2 , the utility model embodiment discloses a motor controller, including: a drive circuit, an overvoltage detection circuit, an n (when the motor is a two-phase motor, n=2; when the motor is a three-phase motor, n=3) phase inverter circuit and n switch circuits;

[0042] The n-phase inverter circuit includes n bridge arms, the output end of each bridge arm is connected to one phase of the motor, and the positive and negative electrodes of each bridge arm are connected to the positive and negative electrodes of the busbar of the motor controller respectively. Figure 1 The positive pole of the busbar is represented as +U bus ), the negative electrode of the busbar is grounded to GND; each bridge arm has two upper and lower switch tubes, the input end of the upper switch tube of the bridge arm is the positive electrode of the bridge arm, the output end of the lower switch tube of the bridge arm is the negative electrode of the bridge arm, and the connection point of the upper switch tube and the lower switch tube of the same bridge arm is the output end of the bridge arm;

[0043] The control end of the upper switch tube of each bridge arm is respectively connected to a high-side drive signal output end O of the drive circuit. HThe control end of the lower switch tube of each bridge arm is connected to the output end of a switch circuit, and the input end of each switch circuit is connected to a low-side drive signal output end O of the drive circuit. L ;

[0044] The input end of the overvoltage detection circuit is connected to the positive pole of the bus +U bus The output end of the overvoltage detection circuit is connected to the control end of the drive circuit and the control end of each switch circuit, and is used to detect the bus voltage U of the motor controller. bus When the preset value is exceeded, the first control signal is output to each switch circuit through its first output terminal O1 and the second control signal is output to the drive circuit through the second output terminal O2;

[0045] The switch circuit is used to enter the off state and pull up the voltage of its own output terminal when receiving the first control signal, so that the lower switch tube connected to its own output terminal is always on;

[0046] The driving circuit is used to enter a prohibited state (ie, a non-enabled state) upon receiving the second control signal, so that the upper switch tube of each bridge arm is normally off.

[0047] Figure 2 Only take n=2 as an example for drawing, Figure 2 The upper and lower switch tubes of one bridge arm are Q2 and Q1 respectively, and the upper and lower switch tubes of the other bridge arm are Q4 and Q3 respectively. The switch circuit corresponding to the lower switch tube Q1 is recorded as switch circuit 1, and the switch circuit corresponding to the lower switch tube Q3 is recorded as switch circuit 2.

[0048] The working principle of the embodiment of the utility model is described in detail below:

[0049] When the motor is reverse-towed, the motor's working mode changes from the first and third quadrants to the second and fourth quadrants (the four quadrants of the motor refer to the four quadrants in the plane rectangular coordinate system with the motor speed as the horizontal axis and the motor torque as the vertical axis). At this time, the motor generates a reverse electromotive force, converts mechanical energy into electrical energy, and charges the battery through the motor controller. When the battery is not connected to the circuit or the battery does not store electricity due to failure, aging, etc., the electrical energy generated by the motor during reverse-tow cannot be absorbed by the battery, and will charge the bus through the body diodes of the n upper switch tubes in the motor controller, resulting in a bus voltage U bus When the bus voltage U bus When it is too high, it will damage the stability and safety of the motor controller.

[0050] To suppress the bus voltage U busThe embodiment of the utility model introduces n switch circuits and overvoltage detection circuits in the motor controller. The switch circuit determines the connection state between its own input terminal and its own output terminal according to the level of its own control terminal, specifically: when the control terminal of the switch circuit is in the enabled state, the switch circuit is normally turned on, that is, the input terminal and the output terminal of the switch circuit are connected; when the control terminal of the switch circuit is in the disabled state, the switch circuit is normally turned off, that is, the input terminal and the output terminal of the switch circuit are blocked. In addition, the embodiment of the utility model is also configured to set the voltage of its own output terminal high while the switch circuit is normally turned off.

[0051] Overvoltage detection circuit at bus voltage U bus When the preset value is not exceeded, the first control signal and the second control signal are not issued. At this time, the working state of the motor controller is mainly reflected in the following two aspects:

[0052] 1) The driving circuit outputs a high-side driving signal to control the switching state of each upper switch tube;

[0053] 2) Each switch circuit is in a normal on state, at which time the drive circuit outputs a low-side drive signal to control the switch state of each lower switch tube.

[0054] The high-side drive and low-side drive mentioned in the embodiment of the utility model are two relative concepts. High-side drive is the process of controlling the switching state of the controllable switches added to the power supply end of the circuit, and the signal that controls the switching state of these controllable switches is called a high-side drive signal; low-side drive is the process of controlling the switching state of the controllable switches added to the ground end of the circuit, and the signal that controls the switching state of these controllable switches is called a low-side drive signal. In the embodiment of the utility model, each upper switch tube in the n-phase inverter circuit belongs to a controllable switch added to the power supply end of the circuit, and each lower switch tube belongs to a controllable switch added to the ground end of the circuit.

[0055] The bus voltage U bus Exceeds the preset value (i.e. bus voltage U bus When the voltage is too high, the working state of the motor controller changes mainly in the following two aspects:

[0056] 1) The overvoltage detection circuit outputs a first control signal to each switch circuit to turn off each switch circuit. After the switch circuit is turned off, the low-side drive signal output terminal O is cut off. L The connection with the control end of the lower switch tube is controlled to be normally on; after each lower switch tube is normally on, the n-phase of the motor is short-circuited to the ground, and energy discharge begins. At this time, the motor enters a state of deceleration or braking, which will suppress the speed of the motor. The back electromotive force generated by the reverse drag of the motor is proportional to the speed. As the speed decreases, the back electromotive force generated by the reverse drag of the motor also decreases, thereby achieving the purpose of preventing the motor controller from being damaged by high voltage;

[0057] 2) The overvoltage detection circuit outputs a second control signal to the drive circuit, so that the drive circuit controls each upper switch tube to be normally off, to prevent the same bridge arm from being directly turned on, that is, to prevent the upper and lower switch tubes of the same bridge arm from being turned on at the same time, causing a power short to ground.

[0058] In summary, the embodiment of the utility model is that the motor is reversely dragged and causes the bus voltage U bus When the bus voltage U is too high, on the one hand, each lower switch tube is normally turned on by turning off each switch circuit, thereby realizing motor short-circuit braking / deceleration and effectively suppressing the bus voltage U bus Too high, making the bus voltage U bus On the other hand, it also controls the drive circuit to enter a non-enabled state, so that each upper switch tube is normally off, thereby avoiding the bridge arm from being directly connected.

[0059] Optionally, based on any of the above disclosed embodiments, the switch tube in the inverter circuit may be a MOS tube or an IGBT, without limitation. Take the switch tube Q1 as an example: when the switch tube Q1 is a MOS tube, the input end of the switch tube Q1 is the drain of the MOS tube, the output end of the switch tube Q1 is the source of the MOS tube, and the control end of the switch tube Q1 is the gate of the MOS tube; when the switch tube Q1 is an IGBT, the input end of the switch tube Q1 is the collector of the IGBT, the output end of the switch tube Q1 is the emitter of the IGBT, and the control end of the switch tube Q1 is the gate of the IGBT.

[0060] Optionally, based on any of the embodiments disclosed above, the first control signal and the second control signal are the same signal. Further, when the first control signal and the second control signal are the same signal, the first control signal may be a high level signal.

[0061] When the first control signal and the second control signal are the same signal, and the first control signal is a high level signal, the overvoltage detection circuit can use a voltage comparator. The input end of the voltage comparator is connected to the positive electrode of the bus +U bus The reference end of the voltage comparator is used to receive a voltage value equal to a preset value (U ref The voltage comparator compares the input voltage with the reference voltage. When the input voltage exceeds the reference voltage, the voltage comparator output level is flipped from a low level to a high level. Figure 3 shown.

[0062] Optionally, based on any of the embodiments disclosed above, the circuit structures of the switch circuits are the same. Figure 4 As shown, the switch circuit 1 includes: a current limiting resistor R1, a switch tube Q5, a current limiting resistor R2, a switch tube Q6 and a current limiting resistor R3;

[0063] Wherein, the low side drive signal output terminal O of the drive circuit L Connected to the output end of the switch tube Q6;

[0064] The input end of the switch tube Q6 is connected to the control end of the lower switch tube Q1;

[0065] The power supply voltage V1 is connected to the control end of the lower switch tube Q1 through the current limiting resistor R3; the power supply voltage V1 is higher than the power supply voltage of the motor controller;

[0066] The power supply voltage V1 is connected to the input end of the switch tube Q5 through the current limiting resistor R1;

[0067] The input end of the switch tube Q5 is connected to the control end of the switch tube Q6 through the current limiting resistor R2;

[0068] The output end of the switch tube Q5 is grounded;

[0069] The control end of the switch tube Q5 is connected to the first output end O1.

[0070] Figure 4 The operating principle of the switching circuit shown is as follows:

[0071] The bus voltage U bus Under normal circumstances, the overvoltage detection circuit does not detect the bus voltage U bus is too high, at this time the first output terminal O1 is at a low level, turning off Q5; after Q5 is turned off, the power supply voltage V1 sets the control terminal of Q6 to a high level through R1 and R2, turning on Q6; after Q6 is turned on, the low-side drive signal can control the switching state of Q1.

[0072] When the motor reverses and causes the bus voltage U bus When the overvoltage detection circuit detects the bus voltage U bus Overvoltage occurs. At this time, the first output terminal O1 flips from a low level to a high level, that is, the first control signal is output to turn on Q5; after Q5 is turned on, the power supply voltage V1 is connected to the ground through R1, and the control terminal of Q6 is connected to the ground through R2. Q6 is in the off state, and the drive circuit cannot output a low-side drive signal to control the switch state of Q1. At this time, the power supply voltage V1 is connected to the control terminal of Q1 through R3, so that Q1 is always on.

[0073] In addition, the working characteristics of the switch tube in the switching circuit determine that it can be normally turned on / off only when the power supply voltage V1 is higher than the power supply voltage VCC of the motor controller. The power supply voltage V1 can be obtained by a boost circuit. The input end of the boost circuit receives the power supply voltage of the motor controller, and the output end is used to output the power supply voltage V1. See Figure 5 .

[0074] Optionally, the boost circuit may use a charge pump or a Boost circuit, etc. For cost considerations, the embodiment of the utility model recommends the use of a charge pump. A charge pump, also known as a switched capacitor voltage converter, is a converter that uses so-called "fast" or "pumping" capacitors (rather than inductors or transformers) to store energy.

[0075] Optional, see Figure 6 Any of the switch circuits 1 disclosed above further includes: a clamping diode D1 and / or a clamping diode D2; the clamping diode D2 is connected between the control end and the output end of the lower switch tube Q1, and the clamping diode D1 is connected between the control end and the output end of the switch tube Q6. The clamping diode D2 plays a role in clamping the voltage between the control end and the output end of the lower switch tube Q1, ensuring that the voltage between the control end and the output end of the lower switch tube Q1 does not exceed the rated value.

[0076] Optionally, in any of the switch circuits 1 disclosed above, the switch tubes Q5 and Q6 may be MOS tubes or IGBTs, without limitation. Figures 4 to 6 In the figure, only the switch tubes Q5 and Q6 using MOS tubes are taken as examples.

[0077] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other and will not be described in detail.

[0078] The terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish between similar different objects, and are not necessarily used to describe a specific order or sequence. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of further restrictions, the elements defined by the sentence "comprising one" do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0079] In the embodiments of the present invention, "and / or" describes the association relationship of the associated objects, indicating that three relationships may exist; for example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B may be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0080] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present invention. Therefore, the embodiments of the present invention will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A motor controller, characterized in that: include: A driving circuit, an overvoltage detection circuit, an n-phase inverter circuit and n switch circuits; n is equal to 2 or 3; The n-phase inverter circuit comprises n bridge arms, the output end of each bridge arm is respectively connected to one phase of the motor, the positive and negative poles of each bridge arm are respectively connected to the positive and negative poles of the busbar of the motor controller, and the negative pole of the busbar is grounded; Each of the bridge arms has two upper and lower switch tubes, and the control end of the upper switch tube of each bridge arm is respectively connected to a high-side drive signal output terminal O of the drive circuit. H The control end of the lower switch tube of each bridge arm is connected to the output end of a switch circuit, and the input end of each switch circuit is connected to a low-side drive signal output end of the drive circuit. L ; The overvoltage detection circuit is used to detect the bus voltage U of the motor controller bus When the preset value is exceeded, a first control signal is output to each switch circuit through the first output terminal O1 and a second control signal is output to the drive circuit through the second output terminal O2; The switch circuit is used to enter a shutdown state and pull up the voltage of its own output terminal when receiving the first control signal, so that the lower switch tube connected to the output terminal of the switch circuit is always turned on; The driving circuit is used to enter a disabled state upon receiving the second control signal, so that the upper switch tube of each bridge arm is normally off.

2. The motor controller according to claim 1, characterized in that: The upper and lower switch tubes of each bridge arm are MOS tubes or IGBTs.

3. The motor controller according to claim 1, characterized in that: The output signals of the first output terminal O1 and the second output terminal O2 are the same, and the first control signal and the second control signal are both high-level signals.

4. The motor controller according to claim 3, characterized in that: The overvoltage detection circuit is a voltage comparator; The input end of the voltage comparator is connected to the positive pole of the bus, and the reference end of the voltage comparator is used to receive a reference signal with a voltage value equal to the preset value; the voltage comparator compares the input end voltage with the reference end voltage, and when the input end voltage exceeds the reference end voltage, the output end of the voltage comparator flips from a low level to a high level.

5. The motor controller according to claim 3 or 4, characterized in that: The circuit structure of each switch circuit is the same; the switch circuit includes: a current limiting resistor R1, a switch tube Q5, a current limiting resistor R2, a switch tube Q6 and a current limiting resistor R3; Wherein, the low side drive signal output terminal O L Connected to the output end of the switch tube Q6; The input end of the switch tube Q6 is connected to the control end of the switch tube under the corresponding bridge arm in the n-phase inverter circuit; The power supply voltage V1 is connected to the control end of the switch tube under the corresponding bridge arm through the current limiting resistor R3; The power supply voltage V1 is connected to the input end of the switch tube Q5 through the current limiting resistor R1; The input end of the switch tube Q5 is connected to the control end of the switch tube Q6 through the current limiting resistor R2; The output end of the switch tube Q5 is grounded; the control end of the switch tube Q5 is connected to the first output end O1; The power supply voltage V1 is higher than the power supply voltage of the motor controller.

6. The motor controller according to claim 5, characterized in that: The switch circuit further includes: a boost circuit; an input end of the boost circuit is used to receive the power supply voltage of the motor controller, and an output end of the boost circuit is used to output the power supply voltage V1.

7. The motor controller according to claim 6, characterized in that: The voltage boost circuit is a charge pump.

8. The motor controller according to claim 5, characterized in that: The switch circuit further includes: a clamping diode D1; the clamping diode D1 is connected between the control end and the output end of the switch tube Q6.

9. The motor controller according to claim 5, characterized in that: The switch circuit further includes: a clamping diode D2; the clamping diode D2 is connected between the control end and the output end of the switch tube under the corresponding bridge arm.

10. The motor controller according to claim 5, characterized in that: The switch tube Q5 and the switch tube Q6 are MOS tubes or IGBTs.

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