Signal generation method for controlling three-phase bridge

Abstract

The invention relates to the control technology of an inverter, and discloses a signal generation method for controlling a three-phase bridge, which comprises the following steps of: performing coordinate conversion on a vector control signal, and converting a vector control signal rectangular coordinate system of the three-phase bridge into a rotating coordinate system; discretizing the converted vector control signal, and discretizing the vector control signal in a rotating coordinate system; and generation of a three-phase vector control signal: generating the three-phase vector control signal for the discrete vector control signal through a space vector algorithm. In order to meet the control time sequence requirement of the three-phase motor, a three-phase vector control signal is converted into a rotating coordinate system through coordinate conversion, then the control signal is discretized, and under the rotating coordinate system, a space vector algorithm is utilized to decompose and calculate six paths of control signals converted by PWM control signal output of a single-chip microcomputer. Cost is low, readability is high, maintenance and optimization are convenient, and reaction speed is high.

Description

Technical Field

[0001] The invention relates to a control technology of an inverter, and in particular to a signal generation method for controlling a three-phase bridge. Background Art

[0002] At present, the control signal of the SI-based three-phase motor is calculated by a method of performing a certain timing control through an FPGA chip to obtain the control signal of the three-phase two-level inverter. Summary of the invention

[0003] The present invention aims at solving the problems of high cost, great difficulty in development and maintenance, and poor readability in calculating the control signal of a three-phase two-level inverter in the prior art, and provides a signal generation method for controlling a three-phase bridge.

[0004] In order to solve the above technical problems, the present invention is solved by the following technical solutions:

[0005] A method for generating a signal to control a three-phase bridge, the method comprising:

[0006] Coordinate conversion of vector control signals, converting the rectangular coordinate system of the vector control signals of the three-phase bridge into a rotating coordinate system;

[0007] The converted vector control signal is discretized in a rotating coordinate system;

[0008] The three-phase vector control signal is generated by using a space vector algorithm to generate the three-phase vector control signal after the discretization.

[0009] As a preferred embodiment: the method includes: obtaining information in the three-phase bridge, the obtained information includes bus voltage, carrier frequency, electrical frequency, water temperature, flow, UVW three-phase AC current and test timing;

[0010] Calculation of the proportional factor: Calculate the proportional factor k based on the bus voltage, carrier frequency, and electrical frequency;

[0011] The combined ratio thus obtains the timer value;

[0012] Output three-phase vector control signal according to the timer value.

[0013] As a preference: calculation of the scaling factor kratio:

[0014] kratio=(pwm_clk / carrier_wave_freq*out_wave_freq*1024 / U dc );

[0015] Among them, pwm_clk is the clock frequency, carrier_wave_freq is the carrier frequency, out_wave_freq is the electrical frequency, U dc is the bus voltage.

[0016] Preferably, the calculation of the timer value includes:

[0017] Calculate the period count value pwm_count according to the carrier frequency and electrical frequency;

[0018] tmp1=carrier_wave_freq / out_wave_freq;

[0019]

[0020] pwm_count = tmp1;

[0021] Among them, pwm_step is the cycle step value, tmp1 is a temporary variable

[0022] Determine the quadrant based on the cycle count value;

[0023] According to the count value and the cycle step value, the corresponding angle value sin_dat is obtained by looking up the table

[0024] sin_dat=sin_tab2[svpwm_count];

[0025] According to the count value pwm_count, the cycle step value and the deviation value, the corresponding angle value cos_dat is obtained by looking up the sin_tab2 table;

[0026] cos_dat=sin_tab2[spwm_count+cos_offset];

[0027] According to the system setting Uq value multiplied by the sin value, we get Ualpha

[0028] Ualpha=-(u q *sin_dat);

[0029] Ubeta=(u q *cos_dat);

[0030] T x =Ubeta;

[0031] T y =-Ualpha-Ubeta;

[0032] T z = -Ualpha + Ubeta;

[0033] Divide the current angle calculation value by the cycle count value to get the current quadrant;

[0034] tmp2=spwm_count / pwm_count;

[0035] Among them, sin_dat is the sin value of the current phase; cos_dat is the cos value of the current phase; cos_offset is the deviation phase value of the current phase; Ualpha is the voltage value of the alpha coordinate in the rectangular coordinate; Ubeta is the voltage value of the beta coordinate in the rectangular coordinate; u q is the voltage value of the q coordinate under the rotating coordinate; T x T is the effective time of phase U; y is the effective time of V phase;

[0036] T z is the effective time of W phase; tmp2 is temporary variable 2; spwm_count is the current phase calculation value;

[0037]

[0038] Determine a timer value according to the determined quadrant;

[0039] tmp3 = T U *Kratio;

[0040] T U =(tmp3>>32);

[0041] tmp3 = T V *Kratio;

[0042] T V =(tmp3>>32);

[0043] tmp3 = T W *Kratio;

[0044] T W =(tmp3>>32);

[0045] T on_A =(pwm_reload-T U -T V )>>2;

[0046] T on_B =(pwm_reload+T V -T W )>>2;

[0047] T on_C=(pwm_reload+T W +T U )>>2;

[0048] Among them, Ton_A is the actual timing time of timer A; Ton_B is the actual timing time of timer B; Ton_C is the actual timing time of timer C; pwm_reload is the preload timer time; tmp3 is temporary variable three.

[0049] In order to solve the above technical problem, the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the signal generation method for controlling a three-phase bridge are implemented.

[0050] In order to solve the above technical problem, the present invention also provides an electronic device, which includes: a memory for storing a computer program; a processor for implementing the steps of the signal generation method for controlling a three-phase bridge when executing the computer program.

[0051] The present invention has significant technical effects due to the adoption of the above technical solution:

[0052] In order to realize the control timing requirements of the three-phase motor, the present invention transforms the three-phase vector control signal into a rotating coordinate system through coordinate transformation, and then discretizes the control signal. In the rotating coordinate system, the space vector algorithm is used to decompose and calculate the 6-way control signal output transformed by the PWM control signal of the single-chip microcomputer.

[0053] The three-phase bridge waveform obtained by the present invention has low cost, high readability, convenient maintenance and optimization, and fast response speed. It is suitable for ARM single-chip microcomputers and integer parameter calculation modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a flow chart of the present invention;

[0055] Figure 2 It is a schematic diagram of the space vector coordinates of the three-phase electric aging voltage of the present invention;

[0056] Figure 3 It is a schematic diagram of the synthetic waveform of the space voltage vector in the first quadrant of the present invention;

[0057] Figure 4 1 is a diagram of the output voltage waveform and current waveform of the present invention. DETAILED DESCRIPTION

[0058] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0059] Example 1

[0060] A method for generating a signal to control a three-phase bridge, the method comprising:

[0061] Coordinate conversion of vector control signals, converting the rectangular coordinate system of the vector control signals of the three-phase bridge into a rotating coordinate system; Figure 2 In the figure, Ⅰ--VI: represent 6 quadrants; V0--V7: represent the voltage vector direction of the three-phase bridge in different opening states; α-β: coordinate system.

[0062] The converted vector control signal is discretized in a rotating coordinate system;

[0063] The three-phase vector control signal is generated by using a space vector algorithm to generate the three-phase vector control signal after the discretization.

[0064] As a preferred embodiment: the method includes: obtaining information in the three-phase bridge, the obtained information includes bus voltage, carrier frequency, electrical frequency, water temperature, flow, UVW three-phase AC current and test timing;

[0065] Calculation of the proportional factor: Calculate the proportional factor k based on the bus voltage, carrier frequency, and electrical frequency;

[0066] The combined ratio thus obtains the timer value;

[0067] Output three-phase vector control signal according to the timer value.

[0068] Calculation of the scaling factor kratio:

[0069] kratio=(pwm_clk / carrier_wave_freq*out_wave_freq*1024 / U dc );

[0070] Among them, pwm_clk is the clock frequency, carrier_wave_freq is the carrier frequency, out_wave_freq is the electrical frequency, U dc is the bus voltage.

[0071] Preferably, the calculation of the timer value includes:

[0072] Calculate the period count value pwm_count according to the carrier frequency and electrical frequency;

[0073] tmp1=carrier_wave_freq / out_wave_freq;

[0074]

[0075] pwm_count = tmp1;

[0076] Among them, pwm_step is the cycle step value, tmp1 is a temporary variable

[0077] Figure 3 In, α-β: coordinate system; T4, T6: turn-on time; Ts: synthesis time; Vout: synthesis voltage; Vfirst, Vsecond: first and second voltage values; Ua, Uβ: voltage values ​​in α-β coordinate system; Θe: angle in rotating coordinate system; quadrant is determined according to the cycle count value;

[0078] According to the count value and the cycle step value, the corresponding angle value sin_dat is obtained by looking up the table

[0079] sin_dat=sin_tab2[svpwm_count];

[0080] According to the count value pwm_count, the cycle step value and the deviation value, the corresponding angle value cos_dat is obtained by looking up the sin_tab2 table;

[0081] cos_dat=sin_tab2[spwm_count+cos_offset];

[0082] According to the system setting Uq value multiplied by the sin value, we get Ualpha

[0083] Ualpha=-(u q *sin_dat);

[0084] Ubeta=9u q *cos_dat);

[0085] T x =Ubeta;

[0086] T y =-Ualpha-Ubeta;

[0087] T z = -Ualpha + Ubeta;

[0088] Divide the current angle calculation value by the cycle count value to get the current quadrant;

[0089] tmp2=spwm_count / pwm_count;

[0090] Among them, sin_dat is the sin value of the current phase; cos_dat is the cos value of the current phase; cos_offset is the deviation phase value of the current phase; Ualpha is the voltage value of the alpha coordinate in the rectangular coordinate; Ubeta is the voltage value of the beta coordinate in the rectangular coordinate; u q is the voltage value of the q coordinate under the rotating coordinate; T x T is the effective time of phase U; y is the effective time of V phase;

[0091] T z is the effective time of W phase; tmp2 is temporary variable 2; spwm_count is the current phase calculation value;

[0092]

[0093] Determine a timer value according to the determined quadrant;

[0094] tmp3 = T U *Kratio;

[0095] T U =(tmp3>>32);

[0096] tmp3 = T V *Kratio;

[0097] T V =(tmp3>>32);

[0098] tmp3 = T W *Kratio;

[0099] T W =(tmp3>>32);

[0100] T on_A =(pwm_reload-T U -T V )>>2;

[0101] T on_B =(pwm_reload+T V -T W )>>2;

[0102] T on_C =(pwm_reload+T W +T U )>>2;

[0103] Among them, Ton_A is the actual timing time of timer A; Ton_B is the actual timing time of timer B; Ton_C is the actual timing time of timer C; pwm_reload is the preload timer time; tmp3 is temporary variable three.

[0104] The sin function uses 600 values ​​to meet the number of cycles under different carrier frequencies and different electrical frequencies; the corresponding value of the Sin function is amplified by 65535 times, which can meet the integer shift operation and improve the calculation rate; the value corresponding to the three-phase current effective value is also amplified by 1024 times to meet the high-precision control requirements and can perform shift operations at the same time; the timer value uses the ARM microcontroller median method to generate a three-phase electric vector control signal with controllable phase difference;

[0105] This algorithm realizes the operation of SiC reactive power aging test with a carrier frequency of 30KHz, an electrical frequency of 1KHz and a three-phase effective current of up to 900A.

Claims

1. A signal generation method for controlling a three-phase bridge, the method comprising: Coordinate conversion of vector control signals, converting the rectangular coordinate system of the vector control signals of the three-phase bridge into a rotating coordinate system; The converted vector control signal is discretized in a rotating coordinate system; The three-phase vector control signal is generated by using a space vector algorithm to generate the three-phase vector control signal after the discretization.

2. A waveform generation method for controlling a three-phase bridge according to claim 1, characterized in that: The method includes: obtaining information in a three-phase bridge, the information obtained includes bus voltage, carrier frequency, electrical frequency, water temperature, flow, UVW three-phase AC current and test timing; Calculation of the proportional factor: Calculate the proportional factor k based on the bus voltage, carrier frequency, and electrical frequency; The combined ratio thus obtains the timer value; Output three-phase vector control signal according to the timer value.

3. A waveform generation method for controlling a three-phase bridge according to claim 1, characterized in that: Calculation of the scaling factor kratio: ； Among them, pwm_clk is the clock frequency, carrier_wave_freq is the carrier frequency ， out_wave_freq is the electrical frequency, U dc is the bus voltage.

4. A waveform generation method for controlling a three-phase bridge according to claim 1, characterized in that: The calculation of the timer value includes: Calculate the period count value pwm_count according to the carrier frequency and electrical frequency; ； ， ； Among them, pwm_step is the cycle step value, tmp1 is a temporary variable Determine the quadrant based on the cycle count value; According to the count value and the cycle step value, the corresponding angle value sin_dat is obtained by looking up the table; ； According to the count value pwm_count, the cycle step value and the deviation value, the corresponding angle value cos_dat is obtained by looking up the sin_tab2 table; ； According to the system settings q Multiply the value by the sin value to get Ualpha; ； ； ； ； ； Divide the current angle calculation value by the cycle count value to get the current quadrant; ； Among them, sin_dat is the sin value of the current phase; cos_dat is the cos value of the current phase; cos_offset is the deviation phase value of the current phase; Ualpha is the voltage value of the alpha coordinate in the rectangular coordinate; Ubeta is the voltage value of the beta coordinate in the rectangular coordinate; u q is the voltage value of the q coordinate under the rotating coordinate; T x T is the effective time of phase U; y is the effective time of V phase; T z is the effective time of W phase; tmp2 is temporary variable 2; spwm_count is the current phase calculation value; ， Determine a timer value according to the determined quadrant; ； ； ； ； ； ； ； ； ； Among them, Ton_A is the actual timing time of timer A; Ton_B is the actual timing time of timer B; Ton_C is the actual timing time of timer C; pwm_reload is the preload timer time; tmp3 is temporary variable three.

5. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a waveform generation method for controlling a three-phase bridge as claimed in any one of claims 1 to 4 are implemented.

6. An electronic device, characterized in that: include: Memory for storing computer programs; A processor, configured to implement the steps of a waveform generation method for controlling a three-phase bridge as claimed in any one of claims 1 to 4 when executing the computer program.

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