Drive method, drive circuit, servo driver and motor device for inverter bridge

Abstract

The application provides a driving method of an inverter bridge, a driving circuit, a servo driver and a motor device. In the driving method of the inverter bridge, voltage vector output time and dead time are set, so that a power switch tube of a jth bridge arm is kept in a conduction state in two adjacent voltage vector output times before switching, the power switch tubes kept in the conduction state are changed in turn and staggeredly, in each dead time, two other power switch tubes kept in the conduction state in a previous voltage vector output time are switched off, the corresponding switching bridge arm and winding complete resonance work, the end voltage of the power switch tube to be turned on is clamped to zero potential, zero voltage conduction is realized, a soft switching mode is formed, and the switching loss is reduced and the power conversion efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of servo motors, and particularly relates to a driving method of an inverter bridge, a driving circuit, a servo driver and a motor device. BACKGROUND

[0002] With the rapid development of power electronics technology, three-phase inverter systems mainly structured by three-phase inverter bridges are widely applied. The three-phase inverter system is a power electronic system for converting direct current into alternating current through SPWM (Sinusoidal Pulse Width Modulation), SVPWM (Space Vector Pulse Width Modulation) and DPWM (Discontinuous Pulse Width Modulation) control methods, and is widely applied to communication, factory and enterprise uninterruptible power supply systems.

[0003] A conventional three-phase inverter system such as a servo driver usually adopts a hard switching circuit for driving the inverter bridge. The hard switching refers to the switching behavior of a power switch tube under voltage or current stress conditions. During the process of turning on and turning off, the power switch tube simultaneously bears high voltage and current, thereby causing high switching loss and great stress of the device, reducing the power conversion efficiency of the inverter bridge. SUMMARY

[0004] The application aims to provide a driving method of an inverter bridge, which reduces the switching loss of the inverter bridge and improves the power conversion efficiency of the inverter bridge.

[0005] The first aspect of the embodiment of the application provides a driving method of an inverter bridge, the inverter bridge comprising a first switching bridge arm, a second switching bridge arm and a third switching bridge arm connected in parallel between input terminals of a power supply, each bridge arm comprising upper and lower bridge arms connected in parallel with a power switch tube, a reverse diode and a capacitor, and the middle points of each bridge arm being connected to three-phase windings of a servo motor one by one.

[0006] The driving method of the inverter bridge comprises:

[0007] adjusting the variation timing and phase shift angle of rising edges and falling edges of each PWM driving signal output to each power switch tube to form a driving cycle, each driving cycle having eight PWM driving signals of driving time periods, and each driving time period comprising a voltage vector output time and a dead time after the voltage vector output time;

[0008] six power switch tubes are turned on according to preset eight different three-bit binary change vectors, and one of the turned-on power switch tubes maintains a conducting state between adjacent two voltage vector output times, wherein 1 of the jth bit of the three-bit binary change vector indicates that the power switch tube of the upper bridge arm of the jth bridge arm is turned on, 0 of the jth bit indicates that the power switch tube of the lower bridge arm of the jth bridge arm is turned on, and j is a value in 1, 2, 3;

[0009] In the dead time between adjacent two voltage vector output times, the remaining power switch tubes except the power switch tube maintaining a conducting state are controlled to be turned off, and the other two switching bridge arms except the switching bridge arm in which the power switch tube is located and the winding of the servo motor are switched to a resonance state, and the voltage across the two power switch tubes to be turned on in the resonance state is clamped to zero potential before the next voltage vector output time.

[0010] Optionally, the two power switch tubes to be turned on in the resonance state correspond to the upper bridge arm or the lower bridge arm in the two switching bridge arms respectively;

[0011] When the power switch tube to be turned on is the upper bridge arm of the switching bridge arm, the capacitor connected in parallel with the power switch tube to be turned on and the corresponding winding are switched to a resonance state, the reverse diode connected in parallel with the power switch tube to be turned on is turned on, and the midpoint of the switching bridge arm in which the power switch tube to be turned on is located is raised to the bus voltage of the positive DC bus;

[0012] When the power switch tube to be turned on is the lower bridge arm of the switching bridge arm, the capacitor connected in parallel with the power switch tube to be turned on and the corresponding winding are switched to a resonance state, the reverse diode connected in parallel with the power switch tube to be turned on is turned on, and the midpoint of the switching bridge arm in which the power switch tube to be turned on is located is lowered to zero voltage of the negative DC bus.

[0013] Optionally, the eight voltage vector output times of each driving cycle are a first voltage vector output time, a second voltage vector output time, a third voltage vector output time, a fourth voltage vector output time, a fifth voltage vector output time, a sixth voltage vector output time, a seventh voltage vector output time and an eighth voltage vector output time respectively;

[0014] In the first voltage vector output time, the first dead time and the second voltage vector output time of the ith driving cycle, the power switch tube maintaining a conducting state is the power switch tube of the upper bridge arm of the first switching bridge arm;

[0015] The power switch tube maintaining the conduction state in the second voltage vector output time, the second dead time and the third voltage vector output time of the i-th driving cycle is the power switch tube of the upper bridge arm of the second switching bridge arm;

[0016] The power switch tube maintaining the conduction state in the third voltage vector output time, the third dead time and the fourth voltage vector output time of the i-th driving cycle is the power switch tube of the lower bridge arm of the first switching bridge arm;

[0017] The power switch tube maintaining the conduction state in the fourth voltage vector output time, the fourth dead time and the fifth voltage vector output time of the i-th driving cycle is the power switch tube of the lower bridge arm of the second switching bridge arm;

[0018] The power switch tube maintaining the conduction state in the fifth voltage vector output time, the fifth dead time and the sixth voltage vector output time of the i-th driving cycle is the power switch tube of the upper bridge arm of the first switching bridge arm;

[0019] The power switch tube maintaining the conduction state in the sixth voltage vector output time, the sixth dead time and the seventh voltage vector output time of the i-th driving cycle is the power switch tube of the upper bridge arm of the second switching bridge arm;

[0020] The power switch tube maintaining the conduction state in the seventh voltage vector output time, the seventh dead time and the eighth voltage vector output time of the i-th driving cycle is the power switch tube of the lower bridge arm of the first switching bridge arm;

[0021] The power switch tube maintaining the conduction state in the eighth voltage vector output time, the eighth dead time and the first voltage vector output time of the (i+1)-th driving cycle is the power switch tube of the lower bridge arm of the second switching bridge arm, i is greater than or equal to 1 and is a positive integer.

[0022] Optionally, in the eight voltage vector output times of each driving cycle, the three-bit binary change vectors are 100, 111, 010, 000, 101, 110, 011 and 001 in sequence;

[0023] When the three-bit binary change vector is 100, the inverter bridge outputs a first preset voltage vector;

[0024] When the three-bit binary change vector is 111, the inverter bridge outputs a zero voltage vector;

[0025] When the three-bit binary change vector is 010, the inverter bridge outputs a second preset voltage vector;

[0026] The inverter bridge outputs a zero voltage vector when the three-bit binary change vector is 000;

[0027] The inverter bridge outputs a third preset voltage vector when the three-bit binary change vector is 101;

[0028] The inverter bridge outputs a fourth preset voltage vector when the three-bit binary change vector is 110;

[0029] The inverter bridge outputs a fifth preset voltage vector when the three-bit binary change vector is 011;

[0030] The inverter bridge outputs a sixth preset voltage vector when the three-bit binary change vector is 001.

[0031] Optionally, the dead time is less than the voltage vector output time.

[0032] Optionally, the output time of the zero voltage vector is less than or equal to the output time of any one of the first preset voltage vector, the second preset voltage vector, the third preset voltage vector, the fourth preset voltage vector, the fifth preset voltage vector and the sixth preset voltage vector.

[0033] A second aspect of the embodiment of the present application provides an inverter bridge driving circuit, which comprises:

[0034] A power supply circuit of a controlled output direct current power supply;

[0035] A signal source circuit of a controlled output six-way PWM driving signal;

[0036] A control circuit connected with the power supply circuit and the signal source circuit respectively, and configured to drive the signal source circuit to implement the steps of the inverter bridge driving method.

[0037] Optionally, the signal source circuit comprises six-way PWM module circuits connected with the control circuit respectively.

[0038] Each PWM module circuit is connected with a controlled end of a power switch tube and controlled to output one of the PWM driving signals.

[0039] A third aspect of the embodiment of the present application provides a servo driver, which comprises an inverter bridge and the inverter bridge driving circuit, and the inverter bridge is connected with the inverter bridge driving circuit correspondingly.

[0040] A fourth aspect of the embodiment of the present application provides a motor device, which comprises a servo motor and the servo driver, and the servo motor is connected with the servo driver correspondingly.

[0041] The beneficial effects of the embodiment of the present application compared with the prior art are: in the driving method of the inverter bridge, by setting the voltage vector output time and the dead time, the power switch tube of the jth bridge arm is maintained in the conduction state in the adjacent two voltage vector output times before the switching of the voltage vector output time, the power switch tube maintained in the conduction state changes in turn and is staggered, and in each dead time, the other two power switch tubes maintained in the conduction state in the previous voltage vector output time are switched to the off state, the corresponding switching bridge arm and winding complete the resonance work, so as to clamp the end voltage of the power switch tube to be turned on to zero potential, realize zero voltage conduction, constitute a soft switching mode, reduce the switching loss and improve the power conversion efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The circuit schematic diagram of the inverter bridge provided for the embodiment of the present application is shown in the figure;

[0043] Figure 2 The waveform schematic diagram of the six-way PWM driving signal provided for the embodiment of the present application is shown in the figure;

[0044] Figure 3 The structure schematic diagram of the driving circuit of the inverter bridge provided for the embodiment of the present application is shown in the figure;

[0045] Figure 4 The structure schematic diagram of the signal source circuit in the driving circuit of the inverter bridge shown in the figure is shown in the figure; Figure 3 The structure schematic diagram of the signal source circuit in the driving circuit of the inverter bridge shown in the figure is shown in the figure;

[0046] Figure 5 The structure schematic diagram of the motor device provided for the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0047] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0048] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0049] The first aspect of the embodiment of the present application proposes a driving method of an inverter bridge 100, as shown in the figure, Figure 1As shown, the inverter bridge 100 includes a first switching bridge arm, a second switching bridge arm and a third switching bridge arm connected in parallel between the power input terminals, the upper bridge arm and the lower bridge arm of each switching bridge arm each include power switching tubes, reverse diodes and capacitors connected in parallel, the upper bridge arm and the lower bridge arm of each bridge arm are connected in series between the power input terminals, and the three midpoints formed by the upper bridge arm and the lower bridge arm are connected to the three-phase windings of the servo motor 200 one by one, and the three-phase windings of the servo motor 200 adopt a Y-type connection mode, that is, one end of each phase winding is connected to form a common terminal, and the other end of each phase winding is connected to the midpoint of the inverter bridge 100.

[0050] The power input terminals are used to receive a direct current power supply, including a positive power terminal of a direct current bus and a negative power terminal of the direct current bus, the input terminals of each upper bridge arm are connected in common and connected to the positive power terminal DC+ of the direct current bus, and the output terminals of each lower bridge arm are connected in common and connected to the negative power terminal DC- of the direct current bus.

[0051] The power switching tubes can be selected as corresponding switching tubes, IGBT power tubes, etc., and the six power switching tubes are divided into a first power switching tube Q1 of the upper bridge arm of the first switching bridge arm, a second power switching tube Q2 of the upper bridge arm of the second switching bridge arm, a third power switching tube Q3 of the upper bridge arm of the third switching bridge arm, a fourth power switching tube Q4 of the lower bridge arm of the first switching bridge arm, a fifth power switching tube Q5 of the lower bridge arm of the second switching bridge arm, and a sixth power switching tube Q6 of the lower bridge arm of the third switching bridge arm.

[0052] The capacitors include parasitic capacitors inside the power switching tubes and / or external capacitors connected in parallel to the power switching tubes, and the reverse diodes are reverse diodes inside the power switching tubes.

[0053] Among them, the capacitors include a first capacitor C1 connected to the first power switching tube Q1, a second capacitor C2 connected to the second power switching tube Q2, a third capacitor C3 connected to the third power switching tube Q3, a fourth capacitor C4 connected to the fourth power switching tube Q4, a fifth capacitor C5 connected to the fifth power switching tube Q5, and a sixth capacitor C6 connected to the sixth power switching tube Q6.

[0054] The reverse diodes include a first reverse diode D1 connected to the first power switching tube Q1, a second reverse diode D2 connected to the second power switching tube Q2, a third reverse diode D3 connected to the third power switching tube Q3, a fourth reverse diode D4 connected to the fourth power switching tube Q4, a fifth reverse diode D5 connected to the fifth power switching tube Q5, and a sixth reverse diode D6 connected to the sixth power switching tube Q6.

[0055] In order to reduce the switching loss caused by hard switching and improve the power conversion efficiency, the SVPWM (Space Vector Pulse Width Modulation) control method is used to drive and control the inverter bridge 100, wherein the SVPWM control method is to regard the inverter bridge 100 and the motor as a whole, control eight basic voltage space vectors, and combine them to obtain voltage space vectors with different positions and amplitudes by acting for different times, and use different voltage space vectors to obtain the locus of the magnetic flux and form a circular rotating magnetic field.

[0056] Specifically, the driving method of the inverter bridge 100 includes:

[0057] The rising edge and falling edge of each PWM drive signal output to each power switch tube are adjusted to form a cyclic driving period, each driving period has eight PWM drive signals of driving time periods, and each driving time period includes a voltage vector output time and a dead time after the voltage vector output time.

[0058] In the eight different voltage vector output times of each driving period, six power switch tubes are turned on according to the preset eight different three-bit binary change vectors, respectively, and three power switch tubes are turned on in each three-bit binary change vector, and one of the power switch tubes turned on is maintained in the on state between adjacent two voltage vector output times, wherein 1 in the jth bit of the three-bit binary change vector indicates that the power switch tube of the upper bridge arm of the jth bridge arm is turned on, 0 in the jth bit indicates that the power switch tube of the lower bridge arm of the jth bridge arm is turned on, and j is a value in 1, 2, and 3.

[0059] In the dead time between adjacent two voltage vector output times, the remaining power switch tubes except the maintained on power switch tube are controlled to be turned off, and the other two switch bridge arms except the switch bridge arm where the turned on power switch tube is located are switched to the resonance state with the winding of the servo motor 200, and the voltages of the two power switch tubes to be turned on in the resonance state are clamped to zero potential before the next voltage vector output time.

[0060] In this embodiment, the DC power supply outputs to the DC bus, and six PWM drive signals are output to the six power switch tubes one by one. The PWM drive signals can be generated before the servo motor 200 is driven, or can be generated by synchronous adaptive debugging during the driving of the servo motor 200. The voltage vector output time and the dead time are adjusted according to the bus voltage and the output voltage of the inverter bridge 100, the corresponding power switch tube is opened with zero voltage, and the soft switching mode is formed.

[0061] Each PWM drive signal presents high-low level change state, when the PWM drive signal outputs high level, the power switch tube is turned on, when the PWM drive signal is low, the power switch tube is turned off. It can be understood that, in order to avoid through, the power switch tubes of the upper bridge arm and the lower bridge arm of the same bridge arm cannot be turned on at the same time, that is, the power switch tubes of the upper bridge arm and the lower bridge arm of the same bridge arm cannot receive high level at the same time.

[0062] Therefore, in the voltage vector output time, the power switch tube conduction mode of each bridge arm is that the power switch tube of the upper bridge arm of one switching bridge arm is turned on and the power switch tubes of the lower bridge arms of the other two switching bridge arms are turned on at the same time, or the power switch tubes of the upper bridge arms of two switching bridge arms are turned on and the power switch tube of the lower bridge arm of the other switching bridge arm is turned on at the same time, or the power switch tubes of the upper bridge arms of three switching bridge arms are turned on at the same time, or the power switch tubes of the lower bridge arms of three switching bridge arms are turned on at the same time.

[0063] Among them, in each voltage vector output time, three of the six power switch tubes are controlled to be turned on, and the three power switch tubes controlled to be turned on are switched in eight combinations in different voltage vector output times, that is, the upper bridge arm and the lower bridge arm in each switching bridge arm are turned on alternatively, and the number of combinations is C2 1 *C2 1 *C2 1 = 8, for example, in the first voltage vector output time, the power switch tube Q1 of the upper bridge arm of the first switching bridge arm is turned on, the power switch tube Q5 of the lower bridge arm of the second switching bridge arm is turned on, and the power switch tube Q6 of the lower bridge arm of the third switching bridge arm is turned on, in the second voltage vector output time, the three upper bridge arms are turned on at the same time, in the third voltage vector output time, the power switch tube Q4 of the lower bridge arm of the first switching bridge arm is turned on, the power switch tube Q2 of the upper bridge arm of the second switching bridge arm is turned on, and the power switch tube of the lower bridge arm of the third switching bridge arm is turned on, and so on.

[0064] According to the conduction mode of the power switch tube, it can be equivalent to the corresponding three-bit binary change vector, 1 represents the upper bridge arm conduction, 0 represents the lower bridge arm conduction, when the power switch tube of the upper bridge arm of one bridge arm is turned on and the power switch tubes of the lower bridge arms of the other two bridge arms are turned on at the same time, the change vectors are 100, 010, and 001 respectively, when the power switch tubes of the upper bridge arms of two bridge arms are turned on and the power switch tube of the lower bridge arm of the other bridge arm is turned on at the same time, the change vectors are 110, 101, and 011 respectively, when the power switch tubes of the upper bridge arms of three bridge arms are turned on and the power switch tubes of the lower bridge arms are turned on at the same time, the change vectors are 111 and 000 respectively.

[0065] Wherein, 111 and 000 represent zero voltage vector, which is invalid vector, at this time, the three-phase winding of the servo motor 200 is short-circuited, the three-phase winding reversely feeds back energy to the DC bus, and the servo motor 200 is in dynamic braking state.

[0066] 100, 010, 001, 110, 101, 011 are effective voltage vectors, at this time, the DC bus outputs power to the three-phase winding, and drives the servo motor 200 to rotate.

[0067] According to different switching modes of the six power switch tubes, the six power switch tubes are controlled to be turned on and off in turn according to preset three-bit binary change vectors in eight voltage vector output time, for example, in turn according to 100, 111, 010, 000, 101, 110, 011, 001, that is, in the first voltage vector output time, the first power switch tube Q1, the fifth power switch tube Q5 and the power switch tube of the lower bridge arm of the sixth bridge arm are controlled to be turned on, in the second voltage vector output time, the first power switch tube Q1, the second power switch tube Q2 and the third power switch tube Q3 are controlled to be turned on, in the third voltage vector output time, the fourth power switch tube Q4, the second power switch tube Q2 and the sixth power switch tube Q6 are controlled to be turned on, and so on, so as to finally realize the corresponding turn-on and turn-off of each power switch tube in the eight voltage vector output time.

[0068] The six power switch tubes can also be turned on and off in turn according to other change vectors such as 001, 111, 010, 000, 101, 011, 110, 100.

[0069] At the same time, in order to control the corresponding power switch tube to be turned on in zero voltage state, realize soft switching structure, in the dead time of each driving cycle, one of the three power switch tubes turned on in the previous voltage vector output time maintains the turned-on state, that is, the power switch tube of the jth bridge arm maintains the turned-on state in the mth voltage vector output time, the mth dead time and the m+1th voltage vector output time, and the power switch tubes maintaining the turned-on state change in turn, that is, the first two bits of the adjacent two binary change vectors have one same value and one different value, and the positions of the same value and the different value change in turn, m is a value in 1-8.

[0070] For example, 100, 111, 010, 000, 101, 110, 011, 001, or 100, 110, 011, 001, 101, 111, 010, 000, or 100, 001, 010, 110, 101, 000, 011, 111, etc.

[0071] For example, in the mth voltage vector output time, the mth dead time and the m+1th voltage vector output time, the power switch tubes maintaining the conducting state are:

[0072] The power switch tube Q1 of the upper bridge arm of the first switching bridge arm, the power switch tube Q2 of the upper bridge arm of the second switching bridge arm, the power switch tube Q4 of the lower bridge arm of the first switching bridge arm, the power switch tube Q5 of the lower bridge arm of the second switching bridge arm, the power switch tube Q1 of the upper bridge arm of the first switching bridge arm, the power switch tube Q2 of the upper bridge arm of the second switching bridge arm, the power switch tube Q4 of the lower bridge arm of the first switching bridge arm, and the power switch tube Q5 of the lower bridge arm of the second switching bridge arm.

[0073] That is, the power switch tube Q1 of the upper bridge arm of the first switching bridge arm maintains the conducting state in the first voltage vector output time, the first dead time and the second voltage vector output time, the power switch tube Q2 of the upper bridge arm of the second switching bridge arm maintains the conducting state in the second voltage vector output time, the second dead time and the third voltage vector output time, and so on. The power switch tube Q5 of the lower bridge arm of the second switching bridge arm maintains the conducting state in the seventh voltage vector output time, the seventh dead time and the eighth voltage vector output time. Meanwhile, corresponding to the numerical change of the change vector, the two power switch tubes Q3 and Q6 of the upper bridge arm and the lower bridge arm of the third switching bridge arm are opposite in the on-off state in the first four voltage vector output times and the last four voltage vector output times, so as to ensure that the two power switch tubes of each bridge arm switch the same number of times in the eight voltage vector output times.

[0074] Meanwhile, in the dead time, in addition to the power switch tube maintaining the conducting state, the other two power switch tubes conducting in the three power switch tubes conducting in the previous voltage vector output time are switched to the off state in the mth dead time, that is, at this time, there is only one power switch tube conducting among the six power switch tubes, the capacitances in the switching bridge arm and the corresponding connected windings form a resonance circuit, the two capacitances in the switching bridge arm charge and discharge, the voltage at the midpoint of the switching bridge arm rises or falls to the preset voltage, the reverse diode of the power switch tube connected in parallel between the midpoint and the DC bus is triggered to conduct, and the voltage across the two power switch tubes conducting according to the next three-bit binary vector is clamped to zero potential, so as to ensure zero voltage conduction at the next voltage vector output time, realize soft switching function, reduce switching loss and improve power conversion efficiency.

[0075] For example, when the binary change vector is 100, the first power switch tube Q1, the fifth power switch tube Q5 and the sixth power switch tube Q6 are all in the on state, the voltage between the UV and UW points is the bus voltage, the winding current of the servo motor 200 starts to rise from the initial value, the servo motor 200 starts to rotate to drive the load, and the power module outputs electric power.

[0076] In the mth dead time, it is assumed that the first power switch tube Q1 maintains the on state, the fifth power switch tube Q5 and the sixth power switch tube Q6 are both in the off state, when the fifth power switch tube Q5 changes from on to off, the fifth capacitor C5 connected with the fifth power switch tube Q5 and the second capacitor C2 connected with the second power switch tube Q2 form a resonant circuit, the fifth capacitor C5 starts to charge and the second capacitor C2 starts to discharge, the voltage of the midpoint V1 point rises, the second reverse diode D2 connected with the second power switch tube Q2 is turned on, and the terminal voltage of the second power switch tube Q2 is 0, so that the zero-voltage turn-on of the second power switch tube Q2 is realized before the m+1 voltage vector output time.

[0077] Similarly, when the sixth power switch tube Q6 changes from on to off, the sixth capacitor C6 connected with the sixth power switch tube Q6 and the third capacitor C3 connected with the third power switch tube Q3 form a resonant circuit, the sixth capacitor C6 starts to charge and the third capacitor C3 starts to discharge, the voltage of the midpoint W1 point of the switch bridge arm rises, the third reverse diode D3 connected with the third power switch tube Q3 is turned on, and the terminal voltage of the third power switch tube Q3 is 0, so that the zero-voltage turn-on of the third power switch tube Q3 can be realized before the m+1 voltage vector output time, that is, in the next time, the binary change vector value is 111, so as to realize the soft switching function of the second power switch tube Q2 and the third power switch tube Q3 turned on according to the next three-bit binary vector 111, reduce the switching loss and improve the power conversion efficiency.

[0078] Among them, the corresponding dead time is adjusted according to the charging and discharging efficiency and the voltage size of the midpoint of the switch bridge arm, and the voltage size of the midpoint after the dead time is discharged is set according to the turn-on voltage of the reverse diode, and optionally, the two power switch tubes to be turned on in the resonant state correspond to the upper bridge arm or the lower bridge arm in the two switch bridge arms where the two power switch tubes are located;

[0079] When the power switch tube to be turned on is the upper bridge arm of the switch bridge arm where the power switch tube is located, the capacitor connected in parallel with the power switch tube to be turned on and the winding connected with the power switch tube to be turned on are switched to the resonant state, the reverse diode connected in parallel with the power switch tube to be turned on is turned on, and the midpoint of the switch bridge arm where the power switch tube to be turned on is located is raised to the bus voltage of the positive direct current bus;

[0080] When the power switch tube to be turned on is the lower bridge arm of the switch bridge arm, the capacitor connected in parallel with the power switch tube to be turned on and the corresponding connected winding switch to the resonance state, the reverse diode connected in parallel with the power switch tube to be turned on is turned on, and the midpoint of the switch bridge arm where the power switch tube to be turned on is located is lowered to the zero voltage of the negative DC bus.

[0081] For example, when the binary change vector is 100, the first power switch tube Q1, the fifth power switch tube Q5 and the sixth power switch tube Q6 are all in the on state, the voltage between UV and Uw is the bus voltage, the winding current of the servo motor 200 starts to rise from the initial value, the servo motor 200 starts to rotate to drive the load, and the power supply module outputs electric power.

[0082] In the next adjacent dead time, assuming that the first power switch tube Q1 maintains the on state, the fifth power switch tube Q5 and the sixth power switch tube Q6 are both in the off state, when the fifth power switch tube Q5 changes from on to off, the winding and the fifth capacitor C5 connected with the fifth power switch tube Q5 and the second capacitor C2 connected with the second power switch tube Q2 form a resonance circuit, the fifth capacitor C5 starts to charge and the second capacitor C2 starts to discharge, the voltage of the midpoint V1 rises, when it rises to the bus voltage, the second reverse diode D2 connected with the second power switch tube Q2 is turned on, the second reverse diode D2 clamps the terminal voltage of the second power switch tube Q2 to 0V, so as to realize the zero voltage turn-on of the second power switch tube Q2 at the next voltage vector output time point.

[0083] Similarly, when the sixth power switch tube Q6 changes from on to off, the winding and the sixth capacitor C6 connected with the sixth power switch tube Q6 and the third capacitor C3 connected with the third power switch tube Q3 form a resonance circuit, the sixth capacitor C6 starts to charge and the third capacitor C3 starts to discharge, the voltage of the midpoint W1 rises, when it rises to the bus voltage, the third reverse diode D3 connected with the third power switch tube Q3 is turned on, the third reverse diode D3 clamps the terminal voltage of the third power switch tube Q3 to 0V, so as to realize the zero voltage turn-on of the third power switch tube Q3 at the next voltage vector output time point, that is, at the next time, the binary change vector value is 111, thereby realizing the soft switching function of the second power switch tube Q2 and the third power switch tube Q3 to be turned on next, reducing the switching loss and improving the power conversion efficiency.

[0084] Or, when the binary change vector is 101, the first power switch tube Q1, the fifth power switch tube Q5 and the third power switch tube Q3 are all in the on state, the voltage between UV and Wv is the bus voltage, the winding current of the servo motor 200 starts to rise from the initial value, the servo motor 200 starts to rotate to drive the load, and the power supply module outputs electric power.

[0085] In the next adjacent dead time, assuming that the first power switch Q1 maintains the on state, the fifth power switch Q5 and the sixth power switch Q6 are both in the off state, when the fifth power switch Q5 changes from on to off, the winding, the fifth capacitor C5 connected with the fifth power switch Q5 and the second capacitor C2 connected with the second power switch Q2 form a resonant circuit, the fifth capacitor C5 starts to charge and the second capacitor C2 starts to discharge, the voltage of the midpoint V1 rises, when it rises to the bus voltage, the second reverse diode D2 connected with the second power switch Q2 is turned on, the second reverse diode D2 clamps the terminal voltage of the second power switch Q2 to 0V, so that the second power switch Q2 can be turned on with zero voltage before the next voltage vector output time.

[0086] Similarly, when the third power switch Q3 changes from on to off, the winding, the sixth capacitor C6 connected with the sixth power switch Q6 and the third capacitor C3 connected with the third power switch Q3 form a resonant circuit, the third capacitor C3 starts to charge and the sixth capacitor C6 starts to discharge, the voltage of the midpoint W1 drops, when it drops to 0V, the sixth reverse diode D6 connected with the sixth power switch Q6 is turned on, the sixth reverse diode D6 clamps the terminal voltage of the sixth power switch Q6 to 0V, so that the sixth power switch Q6 can be turned on with zero voltage before the next voltage vector output time, that is, in the next time, the binary change vector value is 110, thereby realizing the soft switching function of the second power switch Q2 and the sixth power switch Q6 to be turned on next, reducing switching loss and improving power conversion efficiency.

[0087] Among them, the midpoint of each bridge arm corresponds to the connection with the corresponding phase winding of the three-phase winding, and optionally, the midpoint of the first switch bridge arm is used to connect the U-phase winding of the servo motor 200, the midpoint of the second switch bridge arm is used to connect the V-phase winding of the servo motor 200, and the midpoint of the third switch bridge arm is used to connect the W-phase winding of the servo motor 200.

[0088] Corresponding to the connection relationship between the bridge arm and the three-phase winding, in order to realize the sequential driving of the three-phase winding and the sequential on-off of the power switches of the first switch bridge arm and the second switch bridge arm, simplify the driving logic and the waveform change of the PWM driving signal, the eight voltage vector output times of each driving period are respectively the first voltage vector output time, the second voltage vector output time, the third voltage vector output time, the fourth voltage vector output time, the fifth voltage vector output time, the sixth voltage vector output time, the seventh voltage vector output time and the eighth voltage vector output time.

[0089] In the first voltage vector output time, the first dead time and the second voltage vector output time, the power switch maintaining the on state is the power switch Q1 of the upper bridge arm of the first switch bridge arm.

[0090] The power switch tube maintaining the conducting state in the second voltage vector output time, the second dead time and the third voltage vector output time is the power switch tube Q2 of the upper bridge arm of the second switch bridge arm;

[0091] The power switch tube maintaining the conducting state in the third voltage vector output time, the third dead time and the fourth voltage vector output time is the power switch tube Q4 of the lower bridge arm of the first switch bridge arm;

[0092] The power switch tube maintaining the conducting state in the fourth voltage vector output time, the fourth dead time and the fifth voltage vector output time is the power switch tube Q5 of the lower bridge arm of the second switch bridge arm;

[0093] The power switch tube maintaining the conducting state in the fifth voltage vector output time, the fifth dead time and the sixth voltage vector output time is the power switch tube Q1 of the upper bridge arm of the first switch bridge arm;

[0094] The power switch tube maintaining the conducting state in the sixth voltage vector output time, the sixth dead time and the seventh voltage vector output time is the power switch tube Q2 of the upper bridge arm of the second switch bridge arm;

[0095] The power switch tube maintaining the conducting state in the seventh voltage vector output time, the seventh dead time and the eighth voltage vector output time is the power switch tube Q4 of the lower bridge arm of the first switch bridge arm;

[0096] The power switch tube maintaining the conducting state in the eighth voltage vector output time, the eighth dead time and the first voltage vector output time of the next driving period is the power switch tube Q5 of the lower bridge arm of the second switch bridge arm.

[0097] That is, the power switch tube Q1 of the upper bridge arm of the first switch bridge arm maintains the conducting state in the first voltage vector output time, the first dead time and the second voltage vector output time, the power switch tube Q2 of the upper bridge arm of the second switch bridge arm maintains the conducting state in the second voltage vector output time, the second dead time and the third voltage vector output time, and so on, the power switch tube Q5 of the lower bridge arm of the second switch bridge arm maintains the conducting state in the seventh voltage vector output time, the seventh dead time and the eighth voltage vector output time, and simultaneously, corresponding to the numerical change of the change vector, the two power switch tubes Q3, Q6 of the upper bridge arm and the lower bridge arm of the third switch bridge arm are opposite in the on-off state in the first four voltage vector output times and the last four voltage vector output times, so as to ensure that the two power switch tubes of each bridge arm are switched the same number of times in the voltage vector output time.

[0098] Meanwhile, in the dead time, in addition to the power switch tube maintaining the on state, the other two power switch tubes are switched to the off state, that is, at this time, only one power switch tube exists in the six power switch tubes, the capacitor in the bridge arm switched to the off state and the corresponding connected winding form a resonance circuit, the two capacitors of the bridge arm are charged and discharged, the voltage of the midpoint rises or falls to the preset voltage, and the reverse diode of the power switch tube connected between the midpoint and the DC bus is triggered to conduct, so that the voltage across the power switch tube is clamped to zero potential, thereby ensuring zero voltage conduction at the next voltage vector output moment, realizing soft switching function, reducing switching loss and improving power conversion efficiency.

[0099] The on-off sequence of the third switch bridge arm can be selected according to requirements. Optionally, in eight voltage vector output time periods of each driving cycle, the three-bit binary change vectors are 100, 111, 010, 000, 101, 110, 011 and 001 in sequence, wherein 1 in the jth bit of the voltage space vector indicates that the power switch tube of the upper bridge arm of the jth switch bridge arm is turned on, 0 in the jth bit indicates that the power switch tube of the lower bridge arm of the jth switch bridge arm is turned on, and j is one of 1, 2 and 3.

[0100] That is, in the first voltage vector output time period, the power switch tube Q1 of the upper bridge arm of the first switch bridge arm, the power switch tube Q5 of the lower bridge arm of the second switch bridge arm and the power switch tube Q6 of the lower bridge arm of the third switch bridge arm are simultaneously turned on, and output power to the servo motor 200.

[0101] In the second voltage vector output time period, the power switch tube Q1 of the upper bridge arm of the first switch bridge arm, the power switch tube Q2 of the upper bridge arm of the second switch bridge arm and the power switch tube Q3 of the upper bridge arm of the third switch bridge arm are simultaneously turned on, and the three-phase winding UVW of the servo motor 200 is short-circuited, and the output power becomes a dynamic braking process.

[0102] In the third voltage vector output time period, the power switch tube Q4 of the lower bridge arm of the first switch bridge arm, the power switch tube Q2 of the upper bridge arm of the second switch bridge arm and the power switch tube Q6 of the lower bridge arm of the third switch bridge arm are simultaneously turned on, and output power to the servo motor 200.

[0103] In the fourth voltage vector output time period, the power switch tube Q4 of the lower bridge arm of the first switch bridge arm, the power switch tube Q5 of the lower bridge arm of the second switch bridge arm and the power switch tube Q6 of the lower bridge arm of the third switch bridge arm are simultaneously turned on, and the three-phase winding UVW of the servo motor 200 is short-circuited, and the output power becomes a dynamic braking process.

[0104] In the fifth voltage vector output time period, the power switch Q1 of the upper bridge arm of the first switching bridge arm, the power switch Q5 of the lower bridge arm of the second switching bridge arm and the power switch Q3 of the upper bridge arm of the third switching bridge arm are simultaneously turned on, and power is output to the servo motor 200.

[0105] In the sixth voltage vector output time period, the power switch Q1 of the upper bridge arm of the first switching bridge arm, the power switch Q2 of the upper bridge arm of the second switching bridge arm and the power switch Q6 of the lower bridge arm of the third switching bridge arm are simultaneously turned on, and power is output to the servo motor 200.

[0106] In the seventh voltage vector output time period, the power switch Q4 of the lower bridge arm of the first switching bridge arm, the power switch Q2 of the upper bridge arm of the second switching bridge arm and the power switch Q3 of the upper bridge arm of the third switching bridge arm are simultaneously turned on, and power is output to the servo motor 200.

[0107] In the eighth voltage vector output time period, the power switch Q4 of the lower bridge arm of the first switching bridge arm, the power switch Q5 of the lower bridge arm of the second switching bridge arm and the power switch Q3 of the upper bridge arm of the third switching bridge arm are simultaneously turned on, and power is output to the servo motor 200.

[0108] When the three-bit binary change vector is 100, the inverter bridge 100 outputs the first preset voltage vector;

[0109] When the three-bit binary change vector is 111, the inverter bridge 100 outputs the zero voltage vector;

[0110] When the three-bit binary change vector is 010, the inverter bridge 100 outputs the second preset voltage vector;

[0111] When the three-bit binary change vector is 000, the inverter bridge 100 outputs the zero voltage vector;

[0112] When the three-bit binary change vector is 101, the inverter bridge 100 outputs the third preset voltage vector;

[0113] When the three-bit binary change vector is 110, the inverter bridge 100 outputs the fourth preset voltage vector;

[0114] When the three-bit binary change vector is 011, the inverter bridge 100 outputs the fifth preset voltage vector;

[0115] When the three-bit binary change vector is 001, the inverter bridge 100 outputs the sixth preset voltage vector.

[0116] Corresponding to the binary vector change sequence, the inverter bridge 100 outputs the voltage vector in the following order: Figure 2 The working process of one SVPWM driving cycle is specifically explained.

[0117] The first vector output time T11, the binary change vector value is 100, at this time the first power switch tube Q1, the fifth power switch tube Q5, the sixth power switch tube Q6 are all in the on state, output the first preset voltage vector, the voltage between UV, UW two points is the bus voltage, the current in the winding of the servo motor 200 starts to rise from the initial value, the servo motor 200 starts to rotate to drive the load, and the power module outputs the electric power.

[0118] The first dead time T12, at this time the first power switch tube Q1 maintains the on state, and the other power switch tubes are all in the off state, the fifth power switch tube Q5 changes from on to off at the initial moment of the dead time T2, the fifth capacitor C5 is charged, the second capacitor C2 is discharged, the voltage of the midpoint V1 point rises to the bus voltage, the second reverse diode D2 is turned on, the terminal voltage of the second power switch tube Q2 is clamped to 0V, so that the second switch power tube Q2 is realized zero voltage turn-on at the initial moment of the second vector output time T21.

[0119] At the same time, the sixth power switch tube Q6 changes from on to off, the sixth capacitor C6 is charged, the third capacitor C3 is discharged, the voltage of the midpoint W1 point rises to the bus voltage, the third reverse diode D3 is turned on, the terminal voltage of the third power switch tube Q3 is clamped to 0V, so that the third switch power tube Q3 is realized zero voltage turn-on at the initial moment of the second vector output time T21.

[0120] The second voltage vector output time T21, the binary change vector value is 111, the power switch tubes of the three upper bridge arms are all turned on, and the lower bridge arms are all turned off, at this time the output is a zero voltage vector, which is an invalid vector, the motor three-phase winding UVW is short-circuited, and the output power becomes a dynamic braking process.

[0121] The second dead time T22, at this time the second power switch tube Q2 is in the on state, and the other power switch tubes are all in the off state. The first electronic switch tube Q1 changes from on to off, the first capacitor C1 is charged, the fourth capacitor C4 is discharged, the voltage of the midpoint U1 point drops, the fourth reverse diode D4 is turned on, and the terminal voltage of the fourth power switch tube Q4 is 0, so that the switch power tube Q4 is realized zero voltage turn-on at the initial moment of the third vector output time T31.

[0122] The third vector output time T31, the binary change vector is 010, at this time the fourth power switch tube Q4, the second power switch tube Q2, the sixth power switch tube Q6 are all in the on state, output the second preset voltage vector, the voltage between VU, VW two points is the bus voltage, the winding current of the servo motor 200 starts to rise from the initial value, the servo motor 200 starts to rotate to drive the load, and the power module outputs the electric power.

[0123] The third dead time T32, at this time the fourth power switch Q4 is in the on state, and the other power switches are in the off state, the second power switch Q2 changes from on to off, the second capacitor C2 charges and the fifth capacitor C5 discharges, the voltage of the point VI decreases, the fifth reverse diode D5 is turned on, and the voltage of the fifth power switch Q5 is clamped to 0V, so that the zero voltage conduction of the fifth switch power tube Q5 is realized at the initial moment of the fourth vector output time T41.

[0124] The fourth voltage vector output time T41, the binary change vector value is 000, the lower bridge arm is turned on and the upper bridge arm is turned off, at this time the fourth power switch Q4, the fifth power switch Q5 and the sixth power switch Q6 are in the on state, the motor three-phase winding UVW is short-circuited, at this time the output is zero voltage vector, which is invalid vector, and the output power becomes regenerative braking process.

[0125] The fourth dead time T42, at this time the fifth power switch Q5 is in the on state, and the others are in the off state, the fourth power switch Q4 changes from on to off, the fourth capacitor C4 charges and the first capacitor C1 discharges, the voltage of the point U1 rises to the bus voltage, the first reverse diode D1 is turned on, and the voltage of the first power switch Q1 is clamped to 0V, so that the zero voltage conduction of the first switch power tube Q1 is realized at the initial moment of the fifth voltage vector output time T51.

[0126] At the same time, the sixth power switch Q6 changes from on to off, the sixth capacitor C6 charges and the third capacitor C3 discharges, the voltage of the point W rises to the bus voltage, the third reverse diode D3 is turned on, and the voltage of the third power switch Q3 is clamped to 0, so that the zero voltage conduction of the third switch power tube Q3 is realized at the initial moment of the fifth voltage vector output time T5.

[0127] The fifth vector output time T51, the binary change vector value is 101, at this time the first power switch Q1, the fifth power switch Q5 and the third power switch Q3 are in the on state, the third preset voltage vector is output, the voltage between the points UV and WV is the bus voltage, the winding current of the servo motor 200 starts to rise from the initial value, the servo motor 200 starts to rotate to drive the load, and the output electric power.

[0128] The fifth dead time T52, at this time the first power switch Q1 is in the on state, and the others are in the off state, the fifth power switch Q5 changes from on to off, the fifth capacitor C5 charges and the second capacitor C2 discharges, the voltage of the point VI rises to the bus voltage, the second reverse diode D2 is turned on, and the voltage of the second power switch Q2 is clamped to 0V, so that the zero voltage conduction of the second switch power tube Q2 is realized at the initial moment of the sixth voltage vector output time T61.

[0129] At the same time, the third power switch Q3 changes from on to off, the third capacitor C3 charges and the sixth capacitor C6 discharges, the voltage of point W drops to zero, the sixth reverse diode D6 turns on, and the terminal voltage of the sixth power switch Q6 is clamped to 0V, so that the zero voltage turn-on of the sixth switch power tube Q6 is realized at the initial moment of the sixth voltage vector output time T61.

[0130] The sixth vector output time T61, the binary change vector value is 110, at this time the first power switch Q1, the second power switch Q2 and the sixth power switch Q6 are all in the on state, the inverter bridge 100 outputs the fourth preset voltage vector, the voltage between points UW and VW is the bus voltage, the winding current of the servo motor 200 starts to rise from the initial value, the servo motor 200 starts to rotate to drive the load, and the output electric power.

[0131] The sixth dead time T62, at this time the second power switch Q2 is in the on state, and the others are in the off state, the first power switch Q1 changes from on to off, the first capacitor C1 charges and the fourth capacitor C4 discharges, the voltage of point U1 drops to zero, the fourth reverse diode D4 turns on, and the terminal voltage of the fourth power switch Q4 is clamped to 0V, so that the zero voltage turn-on of the fourth switch power tube Q4 is realized at the initial moment of the seventh voltage vector output time T71.

[0132] The sixth power switch Q6 changes from on to off, the sixth capacitor C6 charges and the third capacitor C3 discharges, the voltage of point W rises to the bus voltage, the third reverse diode D3 turns on, and the terminal voltage of the third power switch Q3 is clamped to 0V, so that the zero voltage turn-on of the third switch power tube Q3 is realized at the initial moment of the seventh voltage vector output time T71.

[0133] The seventh voltage vector output time T71, the binary change vector value is 011, the fourth power switch Q4, the second power switch Q2 and the third power switch Q3 are all in the on state, the inverter bridge 100 outputs the fifth preset voltage vector, the voltage between points VU and WU is the bus voltage, the winding current of the servo motor 200 starts to rise from the initial value, the servo motor 200 starts to rotate to drive the load, and the output electric power.

[0134] The seventh dead time T71, at this time the fourth power switch Q4 is in the on state, and the others are in the off state, the second power switch Q2 changes from on to off, the second capacitor C2 charges and the fifth capacitor C5 discharges, the voltage of point V1 drops to zero, the fifth reverse diode D5 turns on, and the terminal voltage of the fifth power switch Q5 is clamped to 0V, so that the zero voltage turn-on of the switch power tube Q5 is realized at the initial moment of the eighth voltage vector output time T81.

[0135] The eighth voltage vector output time T81 is a binary change vector value 001, at this time the fourth power switch Q4, the fifth power switch Q5 and the third power switch Q3 are in the on state, the inverter bridge 100 outputs the sixth preset voltage vector, the voltage between WU and WV is the bus voltage, the winding current of the servo motor 200 starts to rise from the initial value, the servo motor 200 starts to rotate to drive the load, and the output electric power is output.

[0136] The eighth dead time T82 is at this time the power switch Q5 is in the on state, and the others are in the off state, the fourth power switch Q4 changes from on to off, the fourth capacitor C4 charges and the first capacitor C1 discharges, the voltage at U1 rises to the bus voltage, the first reverse diode D1 is turned on, the terminal voltage of the first power switch Q1 is clamped to 0V, so that the zero voltage conduction of the first switch power tube Q1 is realized at the initial moment of the first voltage vector T11 output time of the next SVPWM driving period.

[0137] At the same time, the third power switch Q3 changes from on to off, the third capacitor C3 charges and the fifth capacitor C5 discharges, the voltage at W drops to zero, the sixth reverse diode D6 is turned on, and the terminal voltage of the sixth power switch Q6 is clamped to 0V, so that the zero voltage conduction of the sixth switch power tube Q6 is realized at the initial moment of the first voltage vector output time T11 of the next SVPWM driving period.

[0138] By correspondingly adjusting the length and starting time of each voltage vector output time and dead time, the corresponding sequence of zero voltage conduction control of each power switch is realized, the soft switching function is realized, the switching loss is reduced, and the power conversion efficiency is improved.

[0139] In order to avoid overcharging and over-discharging of the capacitor during resonance, and to avoid the midpoint exceeding the threshold, optionally, the dead time is less than the voltage vector output time.

[0140] At the same time, since the second voltage vector output time and the fourth voltage vector output time are both zero voltage vectors, which are invalid vectors, the motor is in the braking state, and the energy is fed back to the front end. In order to avoid the feedback energy exceeding the output power of the inverter bridge 100, affecting the safety of the inverter bridge 100 and the front-end circuit, optionally, the output time of the zero voltage vector is less than or equal to the output time of any one of the first preset voltage vector, the second preset voltage vector, the third preset voltage vector, the fourth preset voltage vector, the fifth preset voltage vector and the sixth preset voltage vector, so as to ensure that the output power is positive in a single driving period, the servo motor 200 is in the forward running state as a whole, and the driving safety and reliability are improved.

[0141] Based on the above driving method of the inverter bridge 100, like Figure 3As shown, the second aspect of the embodiment of the present application proposes a drive circuit 300 of an inverter bridge, the drive circuit 300 of the inverter bridge comprises:

[0142] a power supply circuit 310 of a controlled output direct current power supply;

[0143] a signal source circuit 320 of a controlled output six-way PWM drive signal;

[0144] a control circuit 330 connected with the power supply circuit 310 and the signal source circuit 320 respectively, the control circuit 330 is used to drive the power supply circuit 310 and the signal source circuit 320 to realize the steps of the drive method of the inverter bridge 100 as above.

[0145] In this embodiment, the power supply circuit 310 is used to provide a direct current power supply to the power supply input end of the inverter bridge 100, the signal source circuit 320 is used to provide six-way PWM drive signals to six-way power switch tubes, at the same time, the control circuit 330 adjusts the phase shift angle, the change timing of rising edge and falling edge of the PWM drive signal output by the signal source circuit 320 according to a logic instruction, so as to control the signal source circuit 320 to output PWM drive signals with eight drive periods to corresponding power switch tubes, and adjust the time length and starting time of corresponding voltage vector output time and dead zone time, realize the corresponding sequence of zero voltage conduction control of each power switch tube, realize the soft switching function, reduce the switching loss, and improve the power conversion efficiency.

[0146] The power supply circuit 310 can select a corresponding structure of the switching power supply circuit 310, such as a rectifier circuit, a voltage reduction circuit, etc., the power supply circuit 310 can also be composed of a corresponding intelligent power module with the inverter bridge 100, the intelligent power module includes a plurality of insulated gate bipolar transistors, an isolation drive circuit, a short circuit protection and a temperature detection circuit, etc. structure, the intelligent power module is connected to an alternating current power supply, and performs rectification and inverter conversion to output three-phase alternating current power supply to the servo motor 200.

[0147] The control circuit 330 can adopt a corresponding type structure of the controller, such as a single-chip microcomputer, a digital processing chip, etc. structure, the controller receives a corresponding logic instruction to drive the signal source circuit 320 to complete the voltage space vector pulse width modulation of the inverter bridge 100, the inverter bridge 100 and the servo motor 200 are regarded as a whole, the inverter bridge 100 is controlled to work according to the tracking circular rotating magnetic field, so as to obtain the locus of the magnetic chain through different voltage vectors.

[0148] The signal source circuit 320 can adopt a corresponding triangular wave circuit, a comparator, etc. structure, outputs the PWM drive signal with corresponding pulse width and phase shift angle through signal comparison, optionally, as Figure 4 As shown, the signal source circuit 320 comprises six-way PWM module circuits connected with the control circuit 330 respectively;

[0149] Each PWM module circuit is connected with a controlled end of a power switch tube, and respectively outputs a PWM drive signal. Figure 4 As shown in the figure, the signal end of the first PWM module circuit 321 is connected with the controlled end of the first power switch tube Q1, the signal end of the second PWM module circuit 322 is connected with the controlled end of the second power switch tube Q2, the signal end of the third PWM module circuit 323 is connected with the controlled end of the third power switch tube Q3, the signal end of the fourth PWM module circuit 324 is connected with the controlled end of the fourth power switch tube Q4, the signal end of the fifth PWM module circuit 325 is connected with the controlled end of the fifth power switch tube Q5, and the signal end of the sixth PWM module circuit 326 is connected with the controlled end of the sixth power switch tube Q6.

[0150] In the embodiment, each PWM module circuit has programmable phase control, rising edge and falling edge delay control, and the programming corresponds to the time length and starting time of the voltage vector output time and dead time, so as to respectively output PWM drive signals with different waveforms to the corresponding power switch tubes, drive the corresponding power switch tubes to realize soft switching function at the initial time of the corresponding voltage vector output time, and reduce the switching loss.

[0151] Each PWM module circuit can adopt a programmable signal source unit, and the signal source unit outputs the pulse width of the PWM drive signal according to the control signal output by the control circuit 330. The signal source unit can be a corresponding triangular wave circuit, a comparison circuit, or a corresponding chip structure, and the specific structure is not limited.

[0152] The application further provides a servo driver 10, which comprises an inverter bridge 100 and a drive circuit 300 of the inverter bridge. The specific structure of the drive circuit 300 of the inverter bridge is referred to the above-mentioned embodiments. Since the servo driver 10 adopts all the technical solutions of the above-mentioned embodiments, it has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here. The drive circuit 300 of the inverter bridge is connected with the inverter bridge 100 correspondingly, and the output end of the inverter bridge 100 is used for connecting the power input end of the servo motor 200, and then connecting the three-phase winding of the servo motor 200.

[0153] In the embodiment, the drive circuit 300 and the inverter bridge 100 constitute the servo driver 10, the inverter bridge 100 of the servo driver 10 realizes the soft switching function under the control of the drive circuit 300, reduces the switching loss of the servo driver 10, and improves the power conversion efficiency, correspondingly, the heat generated by the servo driver 10 is reduced, the temperature rise of the heat sink arranged in the servo driver 10 is low, and a fan for forced air cooling does not need to be arranged, the sealed shell of the servo driver 10 is easy to realize, correspondingly, the waterproof and dustproof level of the servo driver 10 is improved, and the servo driver 10 can be applied to more harsh environments.

[0154] The application further provides a motor device, as shown in the drawings, which comprises a servo motor 200 and a servo driver 10. Figure 5 The servo driver 10 and the servo motor 200 are correspondingly connected, the servo driver 10 adopts voltage space vector pulse width modulation, regards the inverter bridge 100 and the servo motor 200 in the servo driver 10 as a whole, controls the inverter bridge 100 to work according to the tracking circular rotating magnetic field, and obtains the locus of the magnetic chain through different voltage vectors.

[0155] The above-described embodiments are only used to illustrate the technical solutions of the application, rather than limit the same; although the application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently; the modification or replacement does not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solutions of the embodiments of the application, and should be included in the protection scope of the application.

Claims

1. A driving method of an inverter bridge, characterized by, The inverter bridge comprises a first switch bridge arm, a second switch bridge arm and a third switch bridge arm connected in parallel between the input terminals of the power supply, the upper bridge arm and the lower bridge arm of each switch bridge arm each comprise a power switch tube, a reverse diode and a capacitor connected in parallel, and the midpoints of each switch bridge arm are connected to the three-phase windings of the servo motor one by one; The driving method of the inverter bridge comprises: adjusting the rising edge and falling edge of each PWM driving signal output to each power switch tube, and adjusting the phase shift angle to form a circulating driving period, each driving period having eight PWM driving signals of driving time periods, and each driving time period comprising a voltage vector output time and a dead time after the voltage vector output time; wherein, in the eight different voltage vector output times of each driving period, six power switch tubes are turned on according to eight different three-bit binary change vectors, and one of the power switch tubes is maintained in the on state between adjacent two voltage vector output times, wherein 1 in the jth bit of the three-bit binary change vector indicates that the power switch tube of the upper bridge arm of the jth bridge arm is turned on, and 0 in the jth bit indicates that the power switch tube of the lower bridge arm of the jth bridge arm is turned on, and j is a value in 1, 2 and 3; in the dead time between adjacent two voltage vector output times, the remaining power switch tubes except the power switch tube maintained in the on state are controlled to be turned off, and the other two switch bridge arms except the switch bridge arm in which the power switch tube is turned on are switched to a resonance state with the windings of the servo motor, and the voltages of the two power switch tubes to be turned on in the resonance state are clamped to zero potential before the next voltage vector output time.

2. The driving method of the inverter bridge according to claim 1, characterized by, The two power switch tubes to be turned on in the resonance state correspond to the upper bridge arm or the lower bridge arm of the two switch bridge arms respectively; when the power switch tube to be turned on is the upper bridge arm of the switch bridge arm, the capacitor connected in parallel with the power switch tube to be turned on and the corresponding winding are switched to the resonance state, the reverse diode connected in parallel with the power switch tube to be turned on is turned on, and the midpoint of the switch bridge arm in which the power switch tube to be turned on is located is raised to the bus voltage of the positive DC bus; when the power switch tube to be turned on is the lower bridge arm of the switch bridge arm, the capacitor connected in parallel with the power switch tube to be turned on and the corresponding winding are switched to the resonance state, the reverse diode connected in parallel with the power switch tube to be turned on is turned on, and the midpoint of the switch bridge arm in which the power switch tube to be turned on is located is lowered to the zero voltage of the negative DC bus.

3. The driving method of the inverter bridge according to claim 2, characterized by, The eight voltage vector output times of each driving period are a first voltage vector output time, a second voltage vector output time, a third voltage vector output time, a fourth voltage vector output time, a fifth voltage vector output time, a sixth voltage vector output time, a seventh voltage vector output time and an eighth voltage vector output time. The power switch tube maintaining the conducting state in the first voltage vector output time, the first dead time and the second voltage vector output time of the i-th driving cycle is the power switch tube of the upper bridge arm of the first switching bridge arm; The power switch tube maintaining the conducting state in the second voltage vector output time, the second dead time and the third voltage vector output time of the i-th driving cycle is the power switch tube of the upper bridge arm of the second switching bridge arm; The power switch tube maintaining the conducting state in the third voltage vector output time, the third dead time and the fourth voltage vector output time of the i-th driving cycle is the power switch tube of the lower bridge arm of the first switching bridge arm; The power switch tube maintaining the conducting state in the fourth voltage vector output time, the fourth dead time and the fifth voltage vector output time of the i-th driving cycle is the power switch tube of the lower bridge arm of the second switching bridge arm; The power switch tube maintaining the conducting state in the fifth voltage vector output time, the fifth dead time and the sixth voltage vector output time of the i-th driving cycle is the power switch tube of the upper bridge arm of the first switching bridge arm; The power switch tube maintaining the conducting state in the sixth voltage vector output time, the sixth dead time and the seventh voltage vector output time of the i-th driving cycle is the power switch tube of the upper bridge arm of the second switching bridge arm; The power switch tube maintaining the conducting state in the seventh voltage vector output time, the seventh dead time and the eighth voltage vector output time of the i-th driving cycle is the power switch tube of the lower bridge arm of the first switching bridge arm; The power switch tube maintaining the conducting state in the eighth voltage vector output time, the eighth dead time and the first voltage vector output time of the (i+1)-th driving cycle is the power switch tube of the lower bridge arm of the second switching bridge arm, i is greater than or equal to 1 and is a positive integer.

4. The driving method of the inverter bridge according to claim 3, wherein The three-bit binary change vectors in the eight voltage vector output times of each driving cycle are 100, 111, 010, 000, 101, 110, 011 and 001 in sequence; When the three-bit binary change vector is 100, the inverter bridge outputs a first preset voltage vector; When the three-bit binary change vector is 111, the inverter bridge outputs a zero voltage vector; When the three-bit binary change vector is 010, the inverter bridge outputs a second preset voltage vector; When the three-bit binary change vector is 000, the inverter bridge outputs a zero voltage vector; When the three-bit binary change vector is 101, the inverter bridge outputs a third preset voltage vector; When the three-bit binary change vector is 110, the inverter bridge outputs a fourth preset voltage vector; When the three-bit binary change vector is 011, the inverter bridge outputs a fifth preset voltage vector; When the three-bit binary change vector is 001, the inverter bridge outputs a sixth preset voltage vector.

5. The driving method of the inverter bridge according to claim 1, characterized by, The dead time is less than the voltage vector output time.

6. The driving method of the inverter bridge according to claim 4, wherein The output time of the zero voltage vector is less than or equal to the output time of any one of the first preset voltage vector, the second preset voltage vector, the third preset voltage vector, the fourth preset voltage vector, the fifth preset voltage vector and the sixth preset voltage vector.

7. A drive circuit for an inverter bridge, characterized in that The application relates to a controlled output direct current power supply and a servo driver. A power supply circuit of a controlled output direct current power supply; A signal source circuit of a controlled output six-way PWM driving signal; A control circuit connected with the power supply circuit and the signal source circuit respectively, and used for driving the signal source circuit to realize the steps of the driving method of the inverter bridge according to any one of claims 1 to 6.

8. The drive circuit of an inverter bridge as claimed in claim 7, characterized in that The signal source circuit comprises six-way PWM module circuits connected with the control circuit respectively; Each PWM module circuit is connected with the controlled end of a power switch tube and controlled to output one-way PWM driving signal.

9. A servo driver, characterized by The application relates to an inverter bridge and a driving circuit of the inverter bridge according to claim 7 or 8, and the inverter bridge is connected with the driving circuit of the inverter bridge correspondingly.

10. An electric machine arrangement, characterized in that The application relates to a servo motor and a servo driver according to claim 9, and the servo motor is connected with the servo driver correspondingly.

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