Bulk Voltage Control During Charging and Power Feeding Transitions
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Solution Overview
Problem
Existing power systems face challenges in stabilizing voltage control for bulk capacitors during transitions between charging and power feeding modes, leading to potential Under Voltage (UV) and Over Voltage (OV) issues, which can cause abnormality detection and cessation of charging and power feeding.
Innovation Solution
A power system that includes an electrical storage device, voltage converters, an inlet, an outlet, a power converter, a bulk capacitor, and a control device. The control device operates the converters under different modes (charging, power feeding, and power feeding during charging) and adjusts the bulk voltage by a predetermined amount when switching modes to prevent UV and OV.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the operation target for voltage control is switched between voltage converter and power converter during mode transition, then the system can perform charging and power feeding operations, but the bulk capacitor voltage may fall below lower limit (UV) or exceed upper limit (OV) during the switching period
Solution Approach 1:
The control device performs preliminary action by continuing to control the bulk capacitor voltage using the current operation target (voltage converter or power converter) even after the control mode has been switched. This ensures that voltage control is not interrupted during the transition period, preventing UV and OV conditions while allowing the system to successfully switch between charging and power feeding modes.
2Ease of operation
If voltage control is temporarily stopped during operation target switching, then the new operation target can be activated, but the bulk capacitor voltage may become unstable and trigger abnormality detection
Solution Approach 1:
The control device maintains continuity of useful action by ensuring that bulk capacitor voltage control continues uninterrupted during operation target switching. The current operation target remains active for voltage control purposes during the transition, eliminating gaps in voltage regulation and preventing harmful voltage anomalies that would otherwise occur during the switching period.
3Adaptability or versatility
If the bulk capacitor voltage is not controlled during mode transition, then the switching between charging and power feeding can be achieved, but UV or OV occurs causing charging and power feeding to be stopped
Solution Approach 1:
The control device takes preliminary action by maintaining bulk capacitor voltage control through the current operation target during the transition period. This preliminary continuation of control prevents UV and OV conditions that would otherwise cause the system to stop charging and power feeding operations, ensuring continuous productive operation during mode switching.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses the occurrence of UV and OV during mode switching, preventing forced cessation of charging and power feeding, and contributing to energy efficiency by ensuring stable voltage control.
Implementation Method 1
a voltage converter (for example, a DC-DC converter 3 explained below) connected to the electrical storage device
Implementation Method 2
a power converter (for example, a power converter 6 explained below) connected to the inlet and the outlet
Implementation Method 3
a bulk capacitor (for example, a bulk capacitor 23 explained below) included in a power line (for example, power lines 21 and 22 explained below) that connects the voltage converter and the power converter
Implementation Method 4
the control device includes: a charging and power feeding request acquirer (for example, a charging/power feeding request acquirer 81 explained below) configured to acquire a charging and power feeding request for charging to the electrical storage device or power feeding to the external load; and a charging and power feeding controller (for example, a charging and power feeding controller 85 explained below) configured to operate the voltage converter to thereby perform voltage control for a bulk voltage, which is a voltage of the bulk capacitor, under the power feeding mode
Data Source
AI summary
A power system includes a control device configured to operate a DC-DC converter and a power converter. The control device performs bulk voltage control by operating a voltage converter under a power feeding mode and performs the bulk voltage control by operating a power converter under a charging mode and a power feeding during charging mode. When the control mode is switched between the power feeding mode and the power feeding during charging mode according to a charging and power feeding request being acquired, from when the charging and power feeding request is acquired until an operation target of the bulk voltage control is switched between the DC-DC converter and a half PFC circuit of the power converter, the control device boosts or steps down a bulk voltage by a predetermined amount from a point in time when the charging and power feeding request is acquired.