astra_conv:conversion:wiring_logics:wiring_logics
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astra_conv:conversion:wiring_logics:wiring_logics [2014/03/16 13:28] richard |
astra_conv:conversion:wiring_logics:wiring_logics [2014/05/20 17:39] richard |
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| ==== BMS peripherals board ===== | ==== BMS peripherals board ===== | ||
| - | The BMS peripherals board comprises three rather independent circuits that cover different logics tasks. They however share some power supply and signal inputs. | + | The BMS peripherals board, which is located in the rear distribution box, comprises three rather independent circuits that cover different logics tasks. They however share some power supply and signal inputs. |
| - | Please see the circuit diagram and a view of the circuit board below. A top view of the board with explanations of the different terminals and LEDs is provided in the chapter "rear distribution box". | + | The "charger lock" section in principle consists of a conventional relay that disables the traction battery charger when ignition is on. This is a safety measure to avoid that the traction battery is overcharged, since the BMS will wrongly interpret an interruption of the cell loop as "LVC" (low voltage cutoff), when ignition is on. |
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| + | The "HV battery alarm" section combines the three alarms "HV idle voltage", "isolation alarm" and "BMS buzzer", and generates the "HV battery alarm", that is fed to the GSM module. A timer module is intended to mask out "HVC" (high voltage cutoff) events (that only occur at the end of the charging phase and only take a few minutes), so that only LVC events are notified. I however later changed the timer to a very short time (a few seconds), so that it is without effect and now both events will lead to an HV battery alarm. | ||
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| + | The "DCDC control / 12V recharger" microcontroller circuit controls the driver of the DCDC converter. | ||
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| + | The DCDC converter itself and its surrounding circuitry is described in [[astra_conv:conversion:dcdc_converter:dcdc_converter#dc_dc_converter|"dcdc_converter"]]. | ||
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| + | Please see the circuit diagram and a view of the circuit board below. A top view of the board with explanations of the different terminals and LEDs is provided in the chapter [[astra_conv:conversion:distribution_boxes:distribution_boxes#trunk_distribution_box|"trunk distribution box"]]". | ||
| {{:astra_conv:conversion:wiring:bms_peripherals_11.jpg?900|}} | {{:astra_conv:conversion:wiring:bms_peripherals_11.jpg?900|}} | ||
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| === charger lock === | === charger lock === | ||
| - | This circuit is actually only a small conventional relay. It opens the 20mA loop of the HV battery charger und thus disables the device when ignition is on. This shall avoid overcharging of individual traction battery cells: While ignition is on, the BMS system is not able to correctly detect "high voltage threshold crossed" events, but wrongly interprets them as "low voltage threshold crossed" events. Therefore, BMS will not shut down the charger in time while ignition is on. | + | This "circuit" is actually only a small conventional relay. It opens the 20mA loop of the HV battery charger und thus disables the device when ignition is on. This shall avoid overcharging of individual traction battery cells: While ignition is on, the BMS system is not able to correctly detect "high voltage threshold crossed" events, but wrongly interprets them as "low voltage threshold crossed" events. Therefore, BMS will not shut down the charger in time while ignition is on. |
| \\ | \\ | ||
| Line 69: | Line 79: | ||
| === DC/DC control / 12V recharger ==== | === DC/DC control / 12V recharger ==== | ||
| - | This microcontroller circuit controls the DC/DC converter (only "on" and "off"). It switches the DC/DC converter on while ignition is on, if the voltage of the battery has dropped below 12,6V or after some idle time has expired. | + | This microcontroller circuit, based on a Microchip PIC16F690, controls the DC/DC converter (only "on" and "off"). It switches the DC/DC converter on while ignition is on, if the voltage of the battery has dropped below 12,6V or after some idle time has expired. In case of a HV battery alarm, the DC/DC converter will not be run to avoid deep discharge of the HV battery. |
| - | Since I had difficulties implementing interrupts (some memory allocation problem), the program is implemented by some loops and polling of external conditions. | + | Since I had difficulties implementing interrupts (some memory allocation problem), the program is implemented in a dirty way by some loops and polling of external conditions. |
| In paticular, the behaviour is | In paticular, the behaviour is | ||
| Line 82: | Line 92: | ||
| in charging loop: | in charging loop: | ||
| yellow LED = "recharge" output is on (RC6 high) | yellow LED = "recharge" output is on (RC6 high) | ||
| - | SOC is increased by <charge_fac> (variable) every <period> cycles | + | SOC is increased by <charge_fac> (variable) every <period> cycles |
| - | in idle loop: | + | in idle loop: |
| - | yellow LED = "recharge" output is off (RC6 low) | + | yellow LED = "recharge" output is off (RC6 low) |
| SOC is decreased by 1 every <period> cycles | SOC is decreased by 1 every <period> cycles | ||
astra_conv/conversion/wiring_logics/wiring_logics.txt · Last modified: 2014/05/20 17:45 by richard
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