state of charge

bms/App/math/CMakeLists.txt

@@ -2,3 +2,4 @@ add_subdirectory(cb)
 add_subdirectory(pec)
 add_subdirectory(soc)
 add_subdirectory(thermal)
+add_subdirectory(ema)

bms/App/math/ema/CMakeLists.txt

@@ -0,0 +1,7 @@
+# Auto-generated CMake for Flat Module: ema
+add_library(ema STATIC)
+
+file(GLOB SRC_FILES "*.c")
+target_sources(ema PRIVATE ${SRC_FILES})
+
+target_include_directories(ema PUBLIC .)

bms/App/math/ema/ema.c

@@ -0,0 +1,22 @@
+#include "ema.h"
+
+void ema_init(ema_filter_t *filter, float alpha) {
+    filter->alpha = alpha;
+    filter->current_ema = 0.0f;
+    filter->is_initialized = 0;
+}
+
+float ema_update(ema_filter_t *filter, float new_value) {
+
+    // intially, 0 will taint the first few values
+    if (!filter->is_initialized) {
+        filter->current_ema = new_value;
+        filter->is_initialized = 1;
+    } 
+
+    else {
+        filter->current_ema = (filter->alpha * new_value) + 
+                              ((1.0f - filter->alpha) * filter->current_ema);
+    }
+    return filter->current_ema;
+}

bms/App/math/ema/ema.h

@@ -0,0 +1,15 @@
+#ifndef EMA_H
+#define EMA_H
+
+#include <stdint.h>
+
+typedef struct {
+    float alpha;
+    float current_ema;
+    int is_initialized;
+} ema_filter_t;
+
+void ema_init(ema_filter_t *filter, float alpha);
+float ema_update(ema_filter_t *filter, float new_value);
+
+#endif 

bms/App/math/soc/coulomb.h

@@ -1,6 +1,34 @@
-#ifndef COULOMB_H
-#define COULOMB_H
+#ifndef SOC_CURVE_H
+#define SOC_CURVE_H
 
 #include <stdint.h>
+#include <stdbool.h>
 
-#endif
+#define DT_SECONDS 0.05f       // 50 ms time step
+#define DEADZONE_THR 0.01f     // Current deadzone threshold (Amps)
+
+#define SINGLE_18650_CHARGE_CAPACITY 3000
+#define NUM_PARALLEL_CELLS 3
+#define TOTAL_PACK_CAPACITY (SINGLE_18650_CHARGE_CAPACITY * NUM_PARALLEL_CELLS)
+
+static batterymodel_t battery_model;
+static emafilter_t soc_filter;
+static const float q_total_pack = TOTAL_PACK_CAPACITY;
+
+typedef struct {
+    float pack_current;
+    float min_cell_voltage;
+    float max_cell_voltage;
+    float accumulated_coulombs;
+    float delta_charge_since_reset;
+    float system_soc;
+    uint32_t rest_duration_ms;
+} batterymodel_t;
+
+typedef struct {
+    float alpha;
+    float current_ema;
+    bool is_initialized;
+} emafilter_t;
+
+#endif

bms/App/math/soc/soc_curve.h

@@ -0,0 +1,19 @@
+#ifndef SOC_CURVE_H
+#define SOC_CURVE_H
+
+#define SOC_LUT_SIZE 21
+
+// example idk
+
+static const float soc_curve_cell_voltages[SOC_LUT_SIZE] = {
+    3.00F, 3.06f, 3.12f, 3.18f, 3.24f, 3.30F, 3.36f, 3.42f, 3.48f, 3.54f,
+    3.60F, 3.66f, 3.72f, 3.78f, 3.84f, 3.90F, 3.96f, 4.02f, 4.08f, 4.14f, 4.20F
+};
+
+static const float soc_curve_percentages[SOC_LUT_SIZE] = {
+    0.0F,   5.0F,   10.0F,  15.0F,  20.0F,  25.0F,  30.0F,  40.0F,  50.0F,  58.0F,
+    65.0F,  72.0F,  78.0F,  83.0F,  88.0F,  92.0F,  95.0F,  97.0F,  99.0F,  99.5f, 100.0F
+};
+
+
+#endif

bms/CMakeLists.txt

@@ -104,6 +104,7 @@ target_link_libraries(${PROJECT_NAME}
         daemons    
         threads
         gui
+        ema
 )
 
 add_custom_command(TARGET ${PROJECT_NAME} POST_BUILD