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 17:45] (current) 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". | + | 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. |
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| While charging and shortly after, a BMS alarm can only mean "high voltage threshold crossed", which is handled by the battery charger and does not require manual intervention. | While charging and shortly after, a BMS alarm can only mean "high voltage threshold crossed", which is handled by the battery charger and does not require manual intervention. | ||
| Else, a BMS alarm will mean that the low voltage threshold has been crossed at at least one cell. | Else, a BMS alarm will mean that the low voltage threshold has been crossed at at least one cell. | ||
| + | |||
| + | I however later changed the timer in this circuit 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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| === 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 85: | ||
| 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.1394976488.txt · Last modified: 2014/03/16 13:28 by richard
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