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nuttx/libs/libdsp/lib_svm.c
Gustavo Henrique Nihei 330eff36d7 sourcefiles: Fix relative path in file header
2021-03-09 23:18:28 +08:00

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/****************************************************************************
* libs/libdsp/lib_svm.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <assert.h>
#include <dsp.h>
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: svm3_sector_get
*
* Description:
* Get current sector for space vector modulation.
*
* Input Parameters:
* ijk - (in) pointer to the auxiliary ABC frame
*
* Returned Value:
* None
*
****************************************************************************/
static uint8_t svm3_sector_get(FAR abc_frame_t *ijk)
{
uint8_t sector = 0;
float i = ijk->a;
float j = ijk->b;
float k = ijk->c;
/* Identify the correct sector based on i,j,k frame:
* 1. sector 1:
* i > 0.0
* j > 0.0
* k <= 0.0
* 2. sector 2:
* i <= 0.0
* j > 0.0
* k <= 0.0
* 3. sector 3:
* i <= 0.0
* j > 0.0
* k > 0.0
* 4. sector 4:
* i <= 0.0
* j <= 0.0
* k > 0.0
* 5. sector 5:
* i > 0.0
* j <= 0.0
* k > 0.0
* 6. sector 6:
* i > 0.0
* j <= 0.0
* k <= 0.0
*/
if (k <= 0.0)
{
if (i <= 0.0)
{
sector = 2;
}
else
{
if (j <= 0.0)
{
sector = 6;
}
else
{
sector = 1;
}
}
}
else
{
if (i <= 0.0)
{
if (j <= 0.0)
{
sector = 4;
}
else
{
sector = 3;
}
}
else
{
sector = 5;
}
}
/* Return SVM sector */
return sector;
}
/****************************************************************************
* Name: svm3_duty_calc
*
* Description:
* Calculate duty cycles for space vector modulation.
*
* Input Parameters:
* s - (in/out) pointer to the SVM state data
* ijk - (in) pointer to the auxiliary ABC frame
*
* Returned Value:
* None
*
****************************************************************************/
static void svm3_duty_calc(FAR struct svm3_state_s *s, FAR abc_frame_t *ijk)
{
float i = ijk->a;
float j = ijk->b;
float k = ijk->c;
float T0 = 0.0f;
float T1 = 0.0f;
float T2 = 0.0f;
/* Determine T1, T2 and T0 based on the sector */
switch (s->sector)
{
case 1:
{
T1 = i;
T2 = j;
break;
}
case 2:
{
T1 = -k;
T2 = -i;
break;
}
case 3:
{
T1 = j;
T2 = k;
break;
}
case 4:
{
T1 = -i;
T2 = -j;
break;
}
case 5:
{
T1 = k;
T2 = i;
break;
}
case 6:
{
T1 = -j;
T2 = -k;
break;
}
default:
{
/* We should not get here */
DEBUGASSERT(0);
break;
}
}
/* Get null vector time */
T0 = 1.0f - T1 - T2;
/* Calculate duty cycle for 3 phase */
switch (s->sector)
{
case 1:
{
s->d_u = T1 + T2 + T0 * 0.5f;
s->d_v = T2 + T0 * 0.5f;
s->d_w = T0 * 0.5f;
break;
}
case 2:
{
s->d_u = T1 + T0 * 0.5f;
s->d_v = T1 + T2 + T0 * 0.5f;
s->d_w = T0 * 0.5f;
break;
}
case 3:
{
s->d_u = T0 * 0.5f;
s->d_v = T1 + T2 + T0 * 0.5f;
s->d_w = T2 + T0 * 0.5f;
break;
}
case 4:
{
s->d_u = T0 * 0.5f;
s->d_v = T1 + T0 * 0.5f;
s->d_w = T1 + T2 + T0 * 0.5f;
break;
}
case 5:
{
s->d_u = T2 + T0 * 0.5f;
s->d_v = T0 * 0.5f;
s->d_w = T1 + T2 + T0 * 0.5f;
break;
}
case 6:
{
s->d_u = T1 + T2 + T0 * 0.5f;
s->d_v = T0 * 0.5f;
s->d_w = T1 + T0 * 0.5f;
break;
}
default:
{
/* We should not get here */
DEBUGASSERT(0);
break;
}
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: svm3
*
* Description:
* One step of the space vector modulation.
* This is most common of SVM with alternate-reverse null vector.
*
* Voltage vector definitions in 3-phase SVM:
*
* |---------|-----------|--------------------|-----------------|
* | Voltage | swithcing | Line to neutral | Line to line |
* | vector | vectors | voltage | voltage |
* | |-----------|--------------------|-----------------|
* | | a | b | c | Van | Vbn | Vcn | Vab | Vbe | Vca |
* |---------|---|---|---|------|------|------|-----|-----|-----|
* | V0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
* |---------|---|---|---|------|------|------|-----|-----|-----|
* | V1 | 1 | 0 | 0 | 2/3 | -1/3 | -1/3 | 1 | 0 | -1 |
* |---------|---|---|---|------|------|------|-----|-----|-----|
* | V2 | 1 | 1 | 0 | 1/3 | 1/3 | -2/3 | 0 | 1 | -1 |
* |---------|---|---|---|------|------|------|-----|-----|-----|
* | V3 | 0 | 1 | 0 | -1/3 | 2/3 | -1/3 | -1 | 1 | 0 |
* |---------|---|---|---|------|------|------|-----|-----|-----|
* | V4 | 0 | 1 | 1 | -2/3 | 1/3 | 1/3 | -1 | 0 | 1 |
* |---------|---|---|---|------|------|------|-----|-----|-----|
* | V5 | 0 | 0 | 1 | -1/3 | -1/3 | 2/3 | 0 | -1 | 1 |
* |---------|---|---|---|------|------|------|-----|-----|-----|
* | V6 | 1 | 0 | 1 | 1/3 | -2/3 | 1/3 | 1 | -1 | 0 |
* |---------|---|---|---|------|------|------|-----|-----|-----|
* | V7 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
* |---------|---|---|---|------|------|------|-----|-----|-----|
*
* Voltage values given in relation to the bus voltage (Vbus)/
*
* Input Parameters:
* s - (out) pointer to the SVM data
* v_ab - (in) pointer to the modulation voltage vector in alpha-beta
* frame, normalized to magnitude (0.0 - 1.0)
*
* NOTE: v_ab vector magnitude must be in range <0.0, 1.0> to get correct
* SVM3 results.
*
* REVISIT: not sure how we should handle invalid data from user.
* For now we saturate output duty form SVM.
*
* REFERENCE:
* https://e2e.ti.com/group/motor/m/pdf_presentations/665547/download
* pages 32-34
*
****************************************************************************/
void svm3(FAR struct svm3_state_s *s, FAR ab_frame_t *v_ab)
{
DEBUGASSERT(s != NULL);
DEBUGASSERT(v_ab != NULL);
abc_frame_t ijk;
/* Perform modified inverse Clarke-transformation (alpha,beta) -> (i,j,k)
* to obtain auxiliary frame which will be used in further calculations.
*/
ijk.a = -0.5f*v_ab->b + SQRT3_BY_TWO_F*v_ab->a;
ijk.b = v_ab->b;
ijk.c = -ijk.b - ijk.a;
/* Get vector sector */
s->sector = svm3_sector_get(&ijk);
/* Get duty cycle */
svm3_duty_calc(s, &ijk);
/* Saturate output from SVM */
f_saturate(&s->d_u, s->d_min, s->d_max);
f_saturate(&s->d_v, s->d_min, s->d_max);
f_saturate(&s->d_w, s->d_min, s->d_max);
}
/****************************************************************************
* Name: svm3_current_correct
*
* Description:
* Correct ADC samples (int32) according to SVM3 state.
* NOTE: This works only with 3 shunt resistors configuration.
*
****************************************************************************/
void svm3_current_correct(FAR struct svm3_state_s *s,
int32_t *c0, int32_t *c1, int32_t *c2)
{
/* Get best ADC samples according to SVM sector.
*
* In SVM phase current can be sampled only in v0 vector state, when lower
* bridge transistors are turned on.
*
* We ignore sample from phase which has the shortest V0 state and
* estimate its value with KCL for motor phases:
* i_a + i_b + i_c = 0
*/
switch (s->sector)
{
case 1:
case 6:
{
/* Sector 1-6: ignore phase 1 */
*c0 = -(*c1 + *c2);
break;
}
case 2:
case 3:
{
/* Sector 2-3: ignore phase 2 */
*c1 = -(*c0 + *c2);
break;
}
case 4:
case 5:
{
/* Sector 4-5: ignore phase 3 */
*c2 = -(*c0 + *c1);
break;
}
default:
{
/* We should not get here. */
*c0 = 0;
*c1 = 0;
*c2 = 0;
break;
}
}
}
/****************************************************************************
* Name: svm3_init
*
* Description:
* Initialize 3-phase SVM data.
*
* Input Parameters:
* s - (in/out) pointer to the SVM state data
* sat - (in)
*
* Returned Value:
* None
*
****************************************************************************/
void svm3_init(FAR struct svm3_state_s *s, float min, float max)
{
DEBUGASSERT(s != NULL);
DEBUGASSERT(max > min);
memset(s, 0, sizeof(struct svm3_state_s));
s->d_max = max;
s->d_min = min;
}
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